All posts by CPTFeditor

Cancer Prevention and Treatment Fund 5k Run/Walk: Race Results


Bluemont Park, Arlington, Virginia

Sunday, October 3, 2010

##  Name                        G Age City State           Time     M  F     Award

1 Ted Poulos                   M  48 McLean VA            18:33    1         M 1

2  Mark Walchinsky              M  31 Alexandria VA        18:57    2      M25-34 1

3  Jack Kammerer                M  48 Washington DC        19:06    3     M45&over 1

4  Bill Stahr                   M  49 The Plains VA        20:02    4     M45&over 2

5  Jim Casey                    M  45 Arlington VA         20:09    5     M45&over 3

6  Nicholas Anthony Girardi     M  23 Lynbrook NY          21:24    6      M13-24 1

7  Richard R. Cappetto          M  23 Falls Church VA      21:31    7      M13-24 2

8  Steve Duboi                  M  40 Washington DC        21:33    8      M35-44 1

9  Timothy Paul Gerhart         M  25 Arlington VA         22:09    9      M25-34 2

10 Margaret Aker                F  22 Washington DC        22:23       1      F 1

11 Karen Young                  F  42 Boyds MD             22:28       2   F35-44 1

12 Kyle James Schoembs          M  26 Vienna VA            22:58   10      M25-34 3

13 Brian Joseph Femiano         M  28 Centreville VA       23:36   11

14 Judy Abid                    F  30 Alexandria VA        23:43       3   F25-34 1

15 Jeffrey Rini                 M  31 Arlington VA         24:34   12

16 Robert S. Weiner             M  63 Accokeek MD          24:39   13

17 David Drane                  M  35 Alexandria VA        25:04   14      M35-44 2

18 Donald Plant                 M  49 Woodbridge VA        25:18   15

19 Addison Cochrane             F  21 Chicago IL           25:47       4   F13-24 1

20 Alex Crabill                 M  22 Los Angeles CA       25:49   16      M13-24 3

21 Benjamin Stevens             M  24 Herndon VA           25:54   17

22 Tracy Tartaglione            F  35 Leesburg VA          26:34       5   F35-44 2

23 Amy Gray                     F  25 Virginia Beach VA    26:44       6   F25-34 2

24 Sam Desai                    M  32 Arlington VA         26:57   18

25 Matt Weibel                  M  22 Arlington VA         27:05   19

26 Sean Boyd                    M  26 Fairfax VA           27:30   20

27 Maggie Young                 F  27 Herndon VA           27:35       7   F25-34 3

28 Alan Young                   M  33 Herndon VA           27:36   21

29 Carrie Pellegrino            F  34 Sterling VA          27:50       8

30 Michael Allen Coyle          M  38 Arlington VA         28:07   22      M35-44 3

31 Catherine Ann Harner         F  27 Alexandria VA        28:31       9

32 Helen Carroll                F  10 Arlington VA         28:34      10  F12&under 1

33 Jonathan Carroll             M  40 Arlington VA         28:36   23

34 Melissa Pettersen            F  25 Arlington VA         28:51      11

35 Dorothy Sheehan              F  32 Stafford VA          28:53      12

36 Chris Sheehan                M  35 Stafford VA          28:56   24

37 Alicia Colgan                F  39 Stafford VA          28:57      13   F35-44 3

38 Carrie Heath                 F  28 Alexandria VA        29:16      14

39 Liz Guertin                  F  36 Washington DC        29:34      15

40 Rebecca A. Newman            F  33 Washington DC        29:36      16

41 Chris DiVenere               M  39 Chantilly VA         29:40   25

42 Danielle E. Mantz            F  21 College Park MD      30:17      17   F13-24 2

43 Tracy Rimdzius               F  37 Arlington VA         30:28      18

44 Pinsuda Alexander            F  33 Washington DC        30:39      19

45 Stephanie Schoembs           F  24 Vienna VA            30:41      20   F13-24 3

46 Christopher McCaskill        M  44 Alexandria VA        30:50   26

47 Gary Kalman                  M  47 Washington DC        31:02   27

48 Jane Hartman                 F  42 Washington DC        31:05      21

49 Nick Panteleos               M  36 Arlington VA         31:15   28

50 Sarah Jane Niazi             F  23 Annapolis MD         31:24      22

51 Colleen Quinn                F  23 Arlington VA         31:31      23

52 Rebecca Niazi                F  20 Annapolis MD         31:35      24

53 Jessica Johnson              F  33 Alexandria VA        31:50      25

54 David Plant                  M  26 Arlington VA         31:58   29

55 Melissa Kane                 F  12 Dale City VA         32:18      26  F12&under 2

56 Jordan Casey                 F  12 Fredericksburg VA    32:20      27  F12&under 3

57 Kela Casey                   F  36 Fredericksburg VA    32:23      28

58 Taylor Casey                 F  10 Fredericksburg VA    32:39      29

59 Richard Rodriguez            M  18 Arlington VA         32:41   30

60 Jane Wachtmeister            F  25 Washington DC        33:09      30

61 Leslie Klein                 F  29 Arlington VA         33:13      31

62 Linda Brennan                F  41 Vienna VA            33:16      32

63 Lisa Sepassi Weiser          F  33 Herndon VA           33:18      33

64 Michelle Lynn Harrison       F  36 Jeffersonton VA      34:32      34

65 Kari Welch                   F  32 Arlington VA         34:34      35

66 Allyn Brooks-LaSure          M  32 Arlington VA         36:08   31

67 Kelly Griffiths              F  33 Silver Spring MD     36:10      36

68 Jo-Ellen Truelove O'Dell     F  41 Catonsville MD       36:14      37

69 Athena Henderson             F  38 Warrenton VA         36:35      38

70 Tim Ramsey                   M  51 Alexandria VA        36:45   32

71 Megan K. Roberson            F  23 Arlington VA         36:54      39

72 Diane H. Plant               F  52 Woodbridge VA        36:55      40  F45&over 1

73 Laura Mancini                F  25 Mechanicsville MD    37:25      41

74 Colleen McCarthy             F  25 Gaithersburg MD      37:26      42

75 Anne Sidney                  F  40 Falls Church VA      37:38      43

76 Bobby Sidney                 M  40 Falls Church VA      37:39   33

77 Amanda P. Smith              F  30 Dumfries VA          38:34      44

78 Trigie Ealey                 F  40 Arlington VA         38:43      45

79 Jeffrey Smith                M  30 Dumfries VA          38:44   34

80 Maria Panteleos              F  35 Arlington VA         38:45      46

81 Robert Mostow M 57 Washington DC 38:49 35

82 Cynthia Chapman              F  39 Occoquan VA          39:26      47

83 Toula Christou               F  37 Arlington VA         40:01      48

84 Sallie Dewar                 F  36 Arlington VA         44:57      49

85 Shawn Casey                  M  7  Fredericksburg VA    46:05   36     M12&under 1

86 Denise Kane                  F  41 Dale City VA         46:06      50

87 Douglas Johnson              M  64 Dale City VA         47:09   37

88 Tyler Thompson               M  25 Washington DC        50:45   38

89 Kellie K. Powell             F  38 Springfield VA       51:37      51

90 Joel O. Powell               M  40 Springfield VA       51:38   39

91 Joanne Soliman               F  26 Alexandria VA        52:31      52

92 Tanya Dorsey                 F  39 Odenton MD           56:52      53

93 Shirley O. Davis             F  31 Alexandria VA        56:59      54

94 Justin Covert                M  30 Arlington VA        1:06:36  40

95 Vic Cora                     M  40 Arlington VA        1:07:25  41

96 Rosemary Cora                F  40 Arlington VA        1:07:27     55

Doctors were Paid to Praise Hormone Replacement Therapy

September, 2010

The Haunting of Medical Journals: How Ghostwriting Sold “HRT”

This article, written by Adriane Fugh-Berman of Georgetown University Medical Center, which appears in the September 2010 issue of PLoS Medicine, reveals the ethically questionable ways in which Wyeth Pharmaceuticals promoted Prempro, a menopausal hormone replacement medication.

Wyeth paid highly respected physicians to allow their names to be listed as authors of research studies, reviews, commentaries, and letters to the editor, although they had not actually conducted or analyzed the research nor written the articles.  These articles were published in medical journals and widely quoted, persuading doctors that hormone therapy was necessary and beneficial to reduce the detrimental effects of menopause and aging on women.  Research subsequently proved that most of the “benefits” were unfounded, and that the truth was sometimes exactly the opposite of the claims: for example, hormone therapy had a negative rather than positive impact on memory.

Lung Cancer and African Americans

Sarah Miller, RN, Cancer Prevention and Treatment Fund

For years, doctors and medical researchers have been puzzled by the fact that African-Americans are more likely to die from lung cancer than people of any other race or ethnicity, although they are not more likely to smoke. How could this be? Is it because they don’t get diagnosed and treated in time, is it genetic, or is there something else going on? Research indicates that a combination of factors may be responsible for the unequal rates of death from lung cancer.

The Problem

African-Americans are disproportionately affected by lung cancer. The percentage of African-American men diagnosed with lung cancer each year is at least 30% higher than among white men, even though they have similar rates of smoking as white men. In fact, African-American men tend to smoke fewer cigarettes per day than white male smokers. While African-American women are less likely to smoke than white women, they are about as likely to develop lung cancer and die from lung cancer as white women. African-Americans also tend to be diagnosed with lung cancer at a younger age. Research has examined many possible explanations for these differences.

Is it Genetic?

Scientists have recently identified several genes that are linked to lung cancer. People who have these genes and smoke are more likely to develop lung cancer than other smokers. They have also found genes that cause a person to metabolize nicotine differently, which could be a factor in whether a person develops lung cancer.6 Some of these genes have been found to be more common in people with African ancestry. This suggests that genetics may have a role in the higher rates of lung cancer among African-Americans.

Genetics are only a part of the equation, though. There are many other factors that contribute to differences in lung cancer rates and in death from lung cancer.

Does the Type of Cigarettes Matter?

Tobacco companies have a long history of targeting the African-American community with advertisements for menthol cigarettes. As a result, about 80% of African-American smokers smoke menthol cigarettes, compared with only 20% of white American smokers.

Many researchers have tried to find a link between lung cancer and menthol cigarettes. Some have theorized that the “cooling” effect of menthol cigarettes allows menthol smokers to inhale the smoke more deeply, which could cause more damage to their lungs. Others have speculated that menthol cigarettes might be more addictive than regular cigarettes.

While studies have shown that smokers of menthol cigarettes may have a more difficult time quitting, and are more likely to smoke their first cigarette sooner after waking in the morning than people who smoke regular cigarettes, researchers have not been able to find any chemical properties of menthol cigarettes that make them more addictive.

Smokers of menthol cigarettes do not, on average, smoke any more cigarettes in their lifetime than regular cigarette smokers, and research so far has failed to show that menthol cigarettes cause more cases of cancer than other kinds of cigarettes.

The one obvious problem with menthol cigarettes is that the menthol makes cigarette smoke less harsh for first-time smokers. Because, of this, many young teens smoke them. In fact, while smoking is declining among adults and adolescents, menthol cigarettes are becoming increasingly popular among both adults and kids ages 12-17. Since we know that people who begin smoking at younger ages are more likely to become regular smokers, it is troubling that there is a product available that helps teens to start smoking. Although African-American teens start smoking later than white teens, they disproportionately smoke menthol cigarettes.

Does the Environment Affect Lung Cancer Disparities?

Industries that produce heavier air pollution (for example, factories, oil refineries, and chemical plants) are often located in African-American communities. Exposure to pollution from working in or living near these industries can increase a person’s risk for lung cancer.,

A person who smokes and is exposed to air pollution is at higher risk for lung cancer than a smoker who is not exposed to air pollution. People who are exposed to air pollution on the job are at especially high risk. The fact that these polluting industries are frequently located in African American communities and employ members of that community may also help to explain why African-Americans are disproportionately affected by lung cancer.

Is it Because of Differences in Treatment?

While differences in diagnosis and treatment don’t explain why more African-Americans develop lung cancer, it may help to explain the higher death rate from lung cancer among blacks.

One study of all the lung cancer patients in the Florida Cancer Registry found that the survival time for African-American patients diagnosed for lung cancer was shorter than that of white patients. The researchers also found that the entire difference in survival time between African-Americans and whites could be attributed to the fact that white patients tended to get more timely and appropriate treatment.

They concluded that if African-American patients could begin treatment as early as white patients, and were provided the best treatment for their condition, then their survival time would catch up with that of white patients.

Another study found that many patients with a certain type of lung cancer, for which surgical removal of part of the lung offers the best chance for a cure, did not get the proper surgery. Shockingly, only 62% of all patients who would have a good chance of the surgery helping them had the surgery. When the researchers separated the results out by race, 66% of white patients who were appropriate candidates had the surgery while only 55% of African-American patients who were appropriate candidates had the surgery. While this is bad news for all patients with this type of lung cancer, it is worse news for African-Americans since they were substantially less likely than white patients to get the surgery.

Why Don’t African-American Patients Receive the Proper Treatment?

One reason that African American patients are less likely to receive the proper treatment than white Americans may be that they are less likely to have health insurance. While about 13% of white American adults under the age of 65 are uninsured, 21% of African American adults in the same age group are without health insurance. Uninsured patients may decide against treatment because they can’t afford it, or may have a difficult time finding a hospital that is willing to provide the treatment to uninsured patients.

Another reason that African American patients do not always receive the most appropriate care is that there seem to be communication problems between providers and patients.

Studies have found that the type of communication a patient has with a doctor or health care provider has an impact on his or her decision-making about treatments. In the long-term, this has a huge impact on the state of a person’s health.

Health care providers are increasingly pressured to fit more patient visits into shorter time periods. Because of this, providers have less time to spend getting to know each patient. In this type of situation, people tend to make snap judgments.

Providers make a judgment based on their first impression of a person (what they think of that person after glancing at his or her chart and based on personal appearance). This judgment influences the provider’s judgment about what medical information the patient wants or doesn’t want, what type of treatment the patient is likely to find acceptable, and how reliable the person will be with his or her follow-up care.

Patients, too, know that they have only a short time for an appointment. They also may judge a provider based on his or her appearance and make assumptions. They may assume that the provider is very knowledgeable and that they should just do what the provider says. Patients may also assume, based on a snap judgment, that the provider will not respond well to being asked questions, that the provider does not care about the patient, or that the provider is not going to be helpful.

Research has shown that when the provider is of a different race or culture than the patient, these breakdowns in communication are more severe and have more negative results in terms of the quality of care a patient receives.

What is Being Done to Reduce Disparities in Lung Cancer Survival?

While healthcare providers and lawmakers recognize that this is a serious problem, they also recognize that there is no quick fix.

One step that is being taken by medical schools is to try and attract more African-American students. Currently, African-Americans are under-represented in the medical profession. The assumption is that African-American physicians be able to communicate more effectively with African-American patients, and that they will be able to educate their colleagues to do so as well.

Many people are also trying to limit advertising of menthol cigarettes, especially ads that target African-American teens.

Some public health advocates are urging the FDA to ban menthol in cigarettes. Other flavored cigarettes (“bidis”) have already been banned on the principle that they attract teens to smoking and make cigarettes more tolerable. Since we know that menthol also makes smoking more desirable for teens, and since it is a flavoring for cigarettes, it makes sense that it should be banned along with the other flavors. Banning menthol cigarettes would likely reduce the number of African-American teens that smoke, and might help reduce lung cancer deaths among African-American men and women.

References:

Centers for Disease Control and Prevention; Summary Health Statistics for US adults: National Health Interview Survey, December 2008; Vital and Health Statistics, 10 (242), 2009.

Stellman, SD; Chen, Y; Mucsat, JE; Djordjevic, MV; Richie, JP; Lazarus, P; Thompson, S; et.al. Lung Cancer Risk in White and Black Americans.  Annals of Epidemiology. 2003. 13(4). Pp.294-302.

National Cancer Institute; SEER stat fact sheets: Lung and Bronchus. Surveillance Epidemiology and End Results. 2010. Retrieved from: http://seer.cancer.gov/statfacts/html/lungb.html#incidence-mortality

American Lung Association; Too May Cases, Too Many Deaths: Lung Cancer in African-Americans, 2010. Retrieved from http://www.lungusa.org/assets/documents/publications/lung-disease-data/ala-lung-cancer-in-african.pdf  on August 10, 2010.

Hansen HM, Xiao Y, Rice T, Bracci PM, Wrensch MR, Sison JD, Chang JS, et. al; Fine mapping of chromosome 15q25.1 lung cancer susceptibility in African-Americans. Human Molecular Genetics.2010 (Epub ahead of print)

Amos CI, Gorlov IP, Dong Q, Wu X, Zhang H, Lu EY, Scheet P, Greisinger AJ, Mills GB, Spitz MR. Nicotinic acetylcholine receptor region on chromosome 15q25 and lung cancer risk among African-Americans: a case-control study. J Natl Cancer Inst. 2010.102(15):1199-205.

Yerger, VB; Przewoznik, J; & Malone. RE; Racialized Geography, corporate activity, and health disparities: Tobacco industry targeting of inner cities. J Health Care Poor Underserved. 2007;18(4 Suppl):10-38.

Okuyemi KS; Ebersole-Robinson M; Nazir N; & Ahluwalia JS; African-American menthol and nonmenthol smokers: differences in smoking and cessation experiences. J Natl Med Assoc. 2004;96(9):1208-11.

9Muscat, JE; Chen, G; Knipe, A; Stellman, SD; Lazarus, P; & Richie, JP Jr. Effects of menthol on tobacco smoke exposure, nicotine dependence, and NNAL glucuronidation; Cancer Epidemiol Biomarkers Prev. 2009;18(1):35-41

10 Gandhi KK, Foulds J, Steinberg MB, Lu SE, Williams JM; Lower quit rates among African-American and Latino menthol cigarette smokers at a tobacco treatment clinic. Int J Clin Pract. 2009;63(3):360-7.

11 Murray RP; Connett JE; Skeans MA; & Tashkin DP; Menthol cigarettes and health risks in Lung Health Study data. Nicotine Tob Res. 2007;9(1):101-7.

12 Carpenter CL, Jarvik ME, Morgenstern H, McCarthy WJ, London SJ; Ann Epidemiol. Mentholated cigarette smoking and lung-cancer risk. Annals of Epidemiology. 1999;9(2):114-20.

13 Brooks, DR; Palmer, JR; Strom, BL; & Rosenberg, L; Menthol cigarettes and risk of lung cancer; American Journal of Epidemiology, 2003; 158(7), pp. 609-16.

Carballo R. (Epidemiology Branch Chief, CDC’s Office on Smoking and Health). Use of  Menthol Cigarettes by Demographic Group. Power Point delivered at the March 30-31 meeting of the Tobacco Products Scientific Advisory Committee Meeting, FDA. http://www.fda.gov/AdvisoryCommittees/CommitteesMeetingMaterials/TobaccoProductsScientificAdvisoryCommittee/ucm207149.htm

U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Division; Results from the 2008 National Survey in Drug Use and Health: National Findings, 2008. Retrieved from: http://www.oas.samhsa.gov/nsduh/2k8nsduh/2k8Results.pdf   on August 24, 2010.

Elliot, MR; Wang, Y; Lowe, RA; & Kleindorfer, PR; Environmental Justice: Frequency and Severity of U.S. Chemical Industry Accidents and Socioeconomic Status of Surrounding Communities, J Epidemiol Community Health 2004;58:24-30.

Brenner DR, Hung RJ, Tsao MS, Shepherd FA, Johnston MR, Narod S, Rubenstein W, & McLaughlin JR; Lung Cancer in Never-Smokers: A Population-Based, Case-Control Study of Epidemiologic Risk Factors; BMC Cancer. 2010,14;10:285

Yang, RY; Cheung, MC; Byrne, MM; Huang, Y; Nguyen, D; Lally, BE; & Koniaris, LG; Do racial or socioeconomic disparities exist in lung cancer treatment? Cancer. 2010; 116(10) pp. 2437-47.

Cykert, S; Dilworth-Anderson, P; Monroe, MH; Walker, P; McGuire, FR; Corbie, Smith, G; Edwards, LJ; & Bunton, AJ; Factors associated with decision to undergo surgery among patients with newly-diagnosed, early-stage lung cancer; JAMA; 303(23) pp. 2368-76.

Kaiser Family Foundation; The Uninsured: A Primer, 2009. Retrieved from http://www.kff.org/uninsured/upload/7451-05_Data_Tables.pdf on August 30, 2010.

Smedley, BD; Stith, AY; & Nelson, AR; Assessing types of racial and ethnic disparities in care: The clinical encounter. Unequal Treatment: Confronting Racial and Ethnic Disparities in Health Care. pp. 29-79, 2003. National Academies Press, Washington, DC.

Gladwell, M; Blink: The Power of Thinking Without Thinking, 2005,

The Effects of a Controversial Cancer Drug

Diana Zuckerman, PhD, The Washington Post: August 22, 2010

The Aug. 16 front-page article “Breast cancer drug in dispute” was a balanced look at Avastin, but the dueling claims were confusing. Here’s the most important issue: Research shows that breast cancer patients taking Avastin don’t live as long and they have more serious side effects than patients taking placebo. That is why Avastin should not be used for breast cancer, even if it were free. Its cost is not the main point, and politicians need to understand that just because a drug is expensive doesn’t mean it improves health.

The manufacturer is correct that Avastin can delay the progression of breast cancer. So why aren’t Avastin patients living longer? Data indicate that it’s because women taking Avastin are more likely to die from side effects such as stroke and heart disease. If a breast cancer patient takes Avastin, it will not improve her chances of living longer, but her quality of life is more likely to be harmed because of the debilitating conditions linked to the drug.

Avastin may help some breast cancer patients, but it appears that nobody can predict which ones it will help and which ones it will hurt. The research indicates that it harms more breast cancer patients than it helps, which is why its approval for breast cancer should be rescinded. If the manufacturer wants to help breast cancer patients, it should do the research necessary to show who is helped by Avastin and seek approval just for those types of patients.

Diana Zuckerman, Washington

The writer is president of the Cancer Prevention and Treatment Fund of the National Research Center for Women & Families.

Cancer Drug Avastin Has Major Setback

KEZI, July 21, 2010

There’s been a major setback for blockbuster cancer drug Avastin.  A panel of experts says it should no longer be recommended for women with advanced breast cancer.  Avastin aimed to starve tumors by choking off their blood supply.  When it was approved in 2008, it seemed to be working.  Giving women with advanced breast cancers an extra five months before their disease worsened.  But the new studies reveal it wasn’t so.

Diana Zuckerman from the National Research Center for Women said, “It is not saving lives, and in fact women taking this drug seem to die a little sooner than women taking other drugs.”

Avastin will still be used for other cancers. Even if the FDA pulls the plug on it for breast cancer, doctors could offer the drug off-label.  But the price-tag, 50-to 90,000 dollars a year, is one few women could afford.

Cancer Drug Avastin No Longer Recommended for Women with Advanced Breast Cancer

KTNV, July 21, 2010

A panel of Federal health advisors say the cancer drug Avastin should no longer be recommended for women with advanced breast cancer. The panel says the risks outweigh the benefits.

The FDA approved Avastin for breast cancer in 2008 based on a trial showing it significantly lengthened the time until the disease worsened. However, two subsequent studies failed to show the same outcome.

“It is not saving lives and in fact women taking this drug seem to die a little sooner than women taking other drugs,” said Diana Zuckerman.

An estimated 90,000 women have used Avastin for breast cancer.

Statement of Diana Zuckerman, Ph.D., President, Cancer Prevention and Treatment Fund, at the FDA’s Oncologic Drugs Advisory Committee meeting on Avastin

 

Diana Zuckerman, PhD, Cancer Prevention and Treatment Fund, July 20, 2010

I am Paul Brown, and I am glad to present the testimony of Dr. Diana Zuckerman, president of the National Research Center for Women & Families and our Cancer Prevention and Treatment Fund.

Our Center is dedicated to improving the health and safety of adults and children, and we do that by scrutinizing medical and scientific research.  We do not accept contributions from companies that make medical products, so we have no conflicts of interest.

Dr. Zuckerman is also a fellow at the University of Pennsylvania Center for Bioethics.  Her perspective is as a researcher who was previously on the faculty at Yale and Vassar, was trained in epidemiology at Yale Medical School; conducted research at Harvard, and worked on health issues in Congress, at the Institute of Medicine, and for nonprofit organizations.

We had hoped that new research would support the FDA’s decision to give Avastin accelerated approval for first line breast cancer treatment in 2008.  The drug showed promise in an open-label trial, in terms of progression free survival but not overall survival.

As you can see in FDA’s summary, these two new placebo controlled trials indicate that the drug has a much more modest effect on progression free survival than was claimed in 2007, and no improvement in overall survival.  In fact, the placebo patients tend to do better in overall survival.

Simply put, the patients are dying of other causes related to serious adverse reactions such as heart attacks, strokes, and gastro-intestinal perforation.  Even when these are not fatal, it has a terrible impact on the cancer patient’s quality of life.

Metastatic breast cancer is not curable and most people live less than 2 years, so if treatment can’t prolong survival then the focus on treating these stage 4 breast cancer patients needs to be quality of life.

Avastin does not improve either the quantity or quality of life of breast cancer patients, according to these two studies.  It may shorten survival and it certainly harms the quality of life.

In 2007, this Advisory Committee recommended against approval for Avastin but FDA approved it anyway.

We urge you to set the record straight – send the FDA a clear message that this Committee is putting public health first. It is clear that the benefits do not outweigh the risks and that the indication for treatment of metastic breast cancer should be REMOVED from the Avastin label.

Gene Test Will Help Determine Which Women with Breast Cancer Will Benefit from Which Chemotherapy

Blossom Paravattil, Megan Cole, and Brandel France de Bravo, MPH, Cancer Prevention and Treatment Fund

Chemotherapy can save lives, but some types of chemotherapy work better for some patients. In 2010, scientists from the European Breast Cancer Conference announced a new way to determine which breast cancer patients are likely to benefit from which chemotherapy treatments.

The scientists conducted a study called a meta-analysis that looked at four large breast cancer trials with a total of 3,000 patients.  Researchers found that having a defect in chromosome 17 (called CEP17) meant that the patient’s tumor was much more likely to respond to chemotherapy drugs called anthracyclines, in comparison to those without the defect.[1]

Anthracyclines are antibiotics that are used to treat cancer by interfering with the enzymes involved in DNA replication. DNA tells cells how to make copies of themselves. If the DNA gets damaged, the “instructions” can contain errors, which causes cells to multiply uncontrollably, resulting in cancer.[2]

The defect called CEP17 is on the same chromosome as other genes that are associated with breast cancer (such as HER-2), and a simple test known as the FISH (fluorescent in situ hybridization) can detect it. In the meta-analysis, researchers found that more than one in four breast cancer patients (27.5%) had this genetic abnormality or mutation, which is linked to poorer survival rates. The good news for women with CEP17 is that when they are treated with anthracyclines, they are about two-thirds more likely to survive and to not have a recurrence of cancer than women with CEP17 who receive other types of chemotherapy. Just as importantly, the researchers discovered that women who do not have CEP17 should not take anthracyclines, because it will not work for them.

Although there are many factors that determine whether chemotherapy will be effective,  a test to measure CEP17 can help physicians choose the most effective chemotherapy to improve a patient’s chances of survival. Chemotherapy has very unpleasant side effects, and choosing the most effective chemotherapy the first time (rather than trying different types of chemotherapy until one works) helps patients fight cancer more quickly and avoid the drugs that wouldn’t improve their chances of surviving cancer.   More studies are needed to better understand CEP17 and to improve treatment, but this is an important step forward.

References:

  1. Bartlett JMS, Munro A, O’Malley FP, Earle H, Poole CJ, Cardoso F, et al. Duplication of chromosome 17 CEP predicts for anthracycline benefit: evidence from an international meta-analysis of 4 adjuvant breast cancer trials for the HER2/TOP2A meta-analysis study group. 7th European Breast Cancer Conference (EBCC-7)
  2. U.S. National Library of Medicine (2010). What is DNA? Retrieved from <http://ghr.nlm.nih.gov/handbook/basics/dna>

Do Hair Dyes Cause Cancer?

Cancer Prevention and Treatment Fund

Permanent hair dyes produced before 1980 contained ingredients that are now known to cause cancer. These were eliminated from dyes produced in the United States in 1979, when industry-wide changes in the formulation of hair dyes were instituted.

It has generally been assumed that personal use of today’s hair dyes is safe, even though there is some evidence that at least one cancer causing agent–known as 4-ABP–can be present in some dyes or dye-lots. It is not a deliberate ingredient, but an unintentional by-product of the manufacturing process. Another problematic chemical–known as 2,3-Naphthalenediol–was banned from hair dyes in Europe in 2006, but may be present in some US hair products.

Because of continued concerns about the potential risks of such chemicals, along with the observation that the incidence of a type of cancer known as lymphoma has doubled in the last 20 years–while the popularity of permanent hair dyes has also increased–scientists have investigated whether hair dye increases the risk of lymphoma.

The term “lymphoma” refers to cancers of the lymphatic system, including Hodgkin’s disease, non-Hodgkin lymphoma, and multiple myeloma. More that 60,000 people in the United States were diagnosed with lymphoma in 2005, and about half of all lymphoma diagnoses and deaths are among women. However, many more women than men use hair dyes.

A study published in July 2006 looked at the relationship between the use of hair dye and development of lymphoma among almost 5,000 people living in 6 European countries.[1] The researchers determined how many of the lymphoma patients had a history of using hair dyes, compared to a similar population that did not have lymphoma.

Many of the media stories about this research, with headlines like “Study Links Hair Dyes to Cancer,” were misleading, considering the actual findings that were reported. The strongest relationship that the researchers found is a 62% higher risk of lymphoma among people who said they had dyed their hair before 1980 but not after. The next strongest is a 37% higher risk among those whose use of hair dyes started before 1980 and continued after that date. Even though these percentages may sound large, they actually represent extremely small increases in individual and population risk. One way to keep this in perspective is to remember that more than 80% of the people who developed lymphoma said they had never used permanent hair dye. Only 4% of those who did have lymphoma used hair dyes prior to 1980.

When looking at a range of cancer types, including lymphoma, there was still a lack of statistically significant evidence linking hair dye use to risk of cancer. In 2008, researcher Michael Kelsh and his colleagues pooled data from 12 different studies (a meta-analysis) of personal hair dye exposure among men and women and bladder cancer.[2] They found that using hair dye did not increase the risk of bladder cancer.

While most hair dye studies have looked at Caucasian populations, a 2009 study   examined the relationship between personal hair dye use and cancer risk by following a group of 70,366 Chinese women. One interesting finding was that women using hair dyes for 20 or more years were at significantly greater risk for ovarian cancer-with nearly six times the risk of non-users. But, it is important to consider that this is based on a small number of long-time hair dye users, and further research is needed. In general, however, no statistically significant evidence was found between the personal use of hair dye and risk for most cancer types.[3]

Other recent studies have produced similar results. A 2007 article by German researchers Hermann Bolt and Klaus Golka analyzed existing evidence and found no bladder cancer risk from permanent oxidative dyes (these are the kind that are mixed right before using).[4] A 2009 study evaluated the association between personal hair dye use and risk of multiple myeloma among U.S. women. Again, no association was found between “ever reporting hair coloring product use” and myeloma risk among all users, including semi-permanent dye users, permanent dye users, and dark permanent dye users.[5]

Ultimately, the results of previous studies on this topic have been inconsistent and though a few have found small increases in cancer risk, the most convincing ones have not. The results of the current studies, however, do underscore the greater toxicity of older dyes compared to newer ones. The bottom line for now, pending additional research, is that  people who have been using permanent hair dyes since the 1980s appear to be at little to no increased risk of lymphoma or other cancers.

References:

  1. Sanjose S, Benavente Y, Nieters A, Foretova L, Maynadie M, Cocco PL et al (2009). Association between Personal Use of Hair Dyes and Lymphoid Neoplasms in Europe. American Journal of Epidemiology 164(1):47-55. Retrieved from: http://aje.oxfordjournals.org/cgi/content/164/1/47
  2. Kelsh MA, Alexander DD, Kalmes RM, & Buffler PA (2008) Personal use of hair dyes and risk of bladder cancer: a meta-analysis of epidemiologic data. Cancer Cause & Control 19(1):549-558.
  3. Mendelsohn JB, Li Q, Ji B, Shu X, Yang G, Li H et al (2009) Personal use of hair dye and cancer risk in a prospective cohort of Chinese women. Cancer Science, Japanese Cancer Association 100(6):1088-1091. Retrieved from:  http://www.statsci.amss.ac.cn/QZLiPage/Publications_files/J2009/J2009CS.pdf
  4. Bolt HM & Golka K (2007). The Debate on Carcinogenicity of Permanent Hair Dyes: New Insights. Critical Reviews in Toxicology 37(6): 521-536. Retrieved from: http://www.informaworld.com/smpp/content~content=a780908126&db=all
  5. Koutros S, Baris D, Bell E, Zheng T, Zhang Y, Holford TR et al (2009). Use of hair colouring products and risk of multiple myeloma among US women. Occupational and Environmental Medicine 66(1): 68-70. Retrieved from: http://oem.bmj.com/content/66/1/68.abstract

Colon Cancer Screening

Padma Ravichandran, Cancer Prevention and Treatment Fund

Colorectal Cancer (more commonly know as colon cancer) is cancer of the colon (large intestine) or rectum, both of which are part of the digestive system. The digestive system removes nutrients and minerals from the food we eat and beverages we drink, and uses them to help our body function. [1] The colon’s job is to remove water from the food that has been digested. The colon then passes the remains to the rectum, where they are eventually released from the body as fecal matter.[2]

In most cases, people with colon cancer don’t have any symptoms.[3]  However, possible symptoms of colon cancer include: blood in one’s stool, stomach aches and pains that do not go away, and weight loss that cannot be explained.  For information on how to prevent colon cancer, see “Colon Cancer: Who is at risk, and how can it be prevented?

Screening for colon cancer is especially important because when colon cancer is found in the early stages, patients do very well: 9 out of 10 people will be alive five years after their diagnosis and treatment.[4] Colon cancer develops from polyps, or abnormal growths in the colon. Not all polyps become cancerous, but all colon cancers develop from polyps. You can get polyps at any age, but they are more common as you get older.[5] Colon cancer screening checks for these polyps, but it does not show whether the polyp is cancerous or precancerous. The only way to know is to remove the polyp and analyze it.

Screening Methods

There are several methods for colon cancer screening. For a quick look at the advantages and disadvantages of each method, see the chart at the end of this article

There has been a gradual increase in screening rates over the last ten years but even so, only about half of the U.S. population at highest risk gets screened for colon cancer. Studies show that people who don’t get screened are less likely to be insured and less likely to have a primary care physician.  In addition, it is widely known that screening for colon cancer is not fun.  And, some people believe that they do not need to get screened because they are healthy. It is not unusual for a person to get a positive test result (indicating polyps or something that is not normal), but not return for the follow-up test.

While there are various ways to screen for colon cancer, a colonoscopy is usually performed when any of the screening tests show abnormal results and follow-up is necessary. A flexible tube with a tiny camera is used to look inside the colon (the whole colon) and to remove any polyps found. Colonoscopy is used for both screening and treating  which is why it has become the most widely used screening method. It is important to know that a study published in the February 2012 issue of the New England Journal of Medicine found that colonoscopies are even more effective at preventing deaths from colon cancer than previously thought-reducing deaths by more than half.[6]

Researchers in the study found that patients who received colonoscopies and had noncancerous or pre-cancerous growths (polyps) removed, were much less likely to die from colon cancer than people in the general population. People in the general population may not have been screened for colon cancer or may have used different, less effective screening methods. The researchers, who followed most patients for almost 16 years but followed some people for as long as 23, concluded that there was a 53% reduction in the death rate from colon cancer in patients who had colonoscopies and then had polyps removed.6 While the study does not establish whether colonoscopies are better than other screening methods in reducing deaths from colon cancer, it brings welcome news.

The results of the NEJM study reinforce the importance of prevention. The United States Preventive Services Task Force (USPSTF) and the Center for Disease Control and Prevention (CDC) recommend that everyone get screened for colon cancer using FOBT, sigmoidoscopy, or colonoscopy starting at age 50 and continuing until age 75. They do not recommend the Stool DNA Test or Computed Tomography Colonography (“Virtual Colonoscopy”) because there is not enough evidence about the risks and benefits of each of these methods.[7]

USPSTF Recommended Screening Methods

Fecal Occult Blood Test (FOBT)

There are two types of FOBT: the Guaiac and Immunochemical tests. They are both take-home tests that detect the presence of blood in stool. The patient is asked to use a brush or Q-tip like tool to obtain a sample of stool. At the doctor’s office or lab they will run the tests and check for blood or the chemical units that make up blood.[8]

Doctors check for blood because it can indicate that a polyp in the colon or rectum broke and started to bleed.[9]

The guaiac-based fecal occult blood test (gFOBT) uses the chemical guaiac to test for heme.  Heme is part of the protein hemoglobin that is in blood, and it contains the iron that our body uses.[10] To make sure that this test is accurate, you will have to avoid certain foods starting two days before providing the stool sample. You should eat a diet high in fiber, but avoid red meats, vitamin C, and foods that might irritate your digestive system. Unfortunately, the results often inaccurately show that there is blood in the stool when there isn’t, which is why more testing is needed afterwards.

The immunochemical fecal occult blood test (iFOBT) uses antibodies to find blood in the stool. Research shows that the iFOBT is more accurate at detecting blood than the gFOBT and it does not require you to limit what you eat. The drawback, however, is that it is also more expensive. The iFOBT can cost anywhere from $18-$40, while the gFOBT costs a few dollars. Most insurance providers will pay for this test and it is also covered under Medicare once a year.[11]

The CDC recommends getting a FOBT every year.[12] If you have a positive FOBT, meaning there is blood in your stool, then your doctor may recommend that you get a follow-up colonoscopy to check for polyps.

Sigmoidoscopy

The sigmoidoscopy uses a lighted flexible tube (called a sigmoidoscope) with a tiny camera attached to examine the lower section of the colon and the rectum. The tube is inserted through the anus, up the rectum, and into the lower section of the colon. The procedure requires that the lowest part of the colon and rectum be clear of solids. In general, the doctor will prescribe a laxative and/or enema two hours before the procedure. The doctor may also ask the patient to restrict his or her diet to clear liquids for 1-3 days before the procedure.[13]

During the procedure, the doctor looks for inflamed tissue, abnormal growths and ulcers. Doctors can pass tools through the tube and remove any polyps or abnormal tissue. The growths can then be analyzed to determine if it is cancerous or not. Depending on the outcome of the test, the doctor may recommend getting a colonoscopy to check for polyps in the entire colon.

The sigmoidoscopy only lasts about twenty minutes, requires little preparation, and causes only mild discomfort. You may experience some cramping and bloating after the procedure but it usually only lasts about an hour. The drawback is that during the procedure there is a small chance of the colon or rectum tearing. Even though the procedure is less invasive than the colonoscopy, doctors are recommending the colonoscopy more often than the sigmoidoscopy.  Most doctors do not have the equipment for a sigmoidoscopy.  In addition the insurance reimbursement is less for the sigmoidoscopy than the colonoscopy.[14]

CDC recommends getting a sigmoidoscopy every five years. If the doctor finds polyps during the procedure he or she may recommend that you get a follow up colonoscopy.

Colonoscopy

 A colonoscopy is essentially a more comprehensive version of the sigmoidoscopy. The colonoscopy examines the entire colon and rectum using a longer lighted tube called a colonoscope. Similar to the sigmoidoscopy, the patients must clear their colon of solids before undergoing the procedure. The difference is that the colonoscopy requires that the entire colon be cleared, which requires more preparation. The doctor may tell you to go on a clear liquid diet 1-3 days before the procedure. In addition, your doctor will prescribe a laxative, and/or enema the night before the procedure. The laxative can be taken in pill or powder form. The powder form must be dissolved in water and is unpleasant. No matter the method of colon cleansing, the patient will need to use the bathroom several times, usually over several hours.

Because this procedure is so invasive, going even farther into the colon, you will be given anesthesia or some other sedative. Any time you are given anesthesia or medicine to make you less awake or sleepy, there is an added risk.[15] The colonoscope is inserted into the anus, up through the rectum, and into the colon. The doctor can check for inflamed tissue, ulcers, and abnormal growths and remove them if necessary. The removed tissue will then be analyzed to check if it is cancerous or not. The colonoscopy is usually recommended as a screening tool and a follow-up tool. This means that the procedure can be used to initially check for abnormal tissue, or it can be used when any of the other test results are positive for the presence of polyps.[16]

The procedures and recovery time for the colonoscopy is a little longer than the sigmoidoscopy. After the procedure, you will have to wait in the clinic for 1-2 hours until the sedative wears off. You will also need to make arrangements for someone to pick you up, because the doctor will not allow you to drive or take a taxi. As with the sigmoidoscopy, you may also experience cramping or bloating.

Due to how comprehensive and invasive the procedure is, the CDC recommends that you undergo a colonoscopy every 10 years. If they do find polyps during the procedure, they may ask you to repeat the procedure in less than 10 years.

Other Screening Methods

Stool DNA Test

The Stool DNA Test checks for any abnormal cells in the stool. For this test you need to collect an entire bowel movement, which may be unpleasant for some people, and send it in to the lab. There, they will look for certain DNA markers that indicate the presence of cancerous cells. Researchers have found that the Stool DNA Test is not very accurate or reliable. Its ability to detect colon cancer ranges from 20-71% so it is not cost effective to get this test.

Double Contrast Barium Enema (DCBE)

The DCBE uses x-rays and the metallic element Barium to examine the colon. They first clean out the colon and rectum using an enema that contains a solution with Barium. The Barium outlines the colon and rectum so it is more visible in the x-ray. There, doctors will be able to see any polyps or cancerous lesions.

The DCBE is effective at detecting certain growths, but often misses smaller polyps that may become cancerous. In most cases, the cancers that are found during the DCBE can also be found with a colonoscopy. Another concern is the amount of radiation you are exposed to during the procedure.  The DCBE has more exposure to radiation than the CT Colonography, which may lead to other adverse health problems.

Computed Tomography Colonography (CT Colonography)

CT Colonography-often called “Virtual Colonoscopy”-uses x-rays to create detailed visual images of the entire colon and rectum. However, in order to get good x-ray images, the colon and rectum must be cleared of solids by way of a clear liquid diet, enema, and/or laxative. As mentioned above, the laxative may be taken in pill or powder form. The powder form must be dissolved in water and is unpleasant. No matter the method of colon cleansing, the patient will need to use the bathroom several times, usually over several hours.

Once the x-ray images have been taken, a computer is used to assemble the pictures together to create a detailed picture of your colon and rectum. If the picture shows polyps or other abnormalities, a regular colonoscopy will be needed immediately to remove them.

Patients tend to prefer the CT Colonography because it is less invasive and causes less discomfort. This method is effective at identifying abnormal growths, but is not effective at identifying abnormal lesions that are flat or depressed. Another concern with the CT Colonography is exposure to radiation from the x-rays, which can increase your risk of getting cancer in the future even as it helps diagnose whether you have cancer currently.  Since the need to clear colon and rectum of solids with a laxative or enema is generally considered the worst part of a colonoscopy, the small advantages of the CT Colonography probably does not outweigh the decrease in accuracy and increase in radiation.

 

Procedure

Advantages

Disadvantages

   FOBT

·  Preparation for the test is minimal

·  Sample can be collected at home

·  Very inexpensive

·  Getting “false-positive” results is common (you may be told you have a problem or something abnormal when you don’t).

·  Does not effectively detect all polyps and cancers

·  You must avoid certain foods for a  few days before collecting stool sample

·  Positive results may require additional tests, such as colonoscopy

 Sigmoidoscopy

·  Quick procedure with minimal discomfort

·  Doctor can remove polyps during procedure

·  Only requires that the lowest part of the colon be clear

·  Does not examine the entire colon—only the lowest part of the colon and the rectum

·  Small risk of bleeding or tearing in colon

·  Positive results may require additional tests, such as colonoscopy

 Colonoscopy

·  Doctor can view entire colon and rectum whereas sigmoidoscopy only looks at lower colon

·  Doctor can remove polyps during procedure

·  Is one of the most sensitive colon cancer screening tests available

·  May not find all polyps or growths

·  Preparation involves clearing entire colon through clear liquid diet and/or enema

·  Patient sedated during procedure

·  Procedure time varies depending on how many polyps are found

·  Patient must be picked up or driven home by someone else afterwards

·  Small risk of bleeding or tearing in colon

 Stool DNA Test

·  Preparation for the test is minimal

·  Not invasive, so no risk of bleeding or tearing

·   Must provide entire bowel movement for testing

·  Not always accurate or reliable

 Double Contrast Barium Enema

·  Doctor can view entire colon and rectum

·  Complications rare

·  No sedation necessary

·  May not find all polyps or growths

·  Preparation involves thorough cleansing of entire colon through clear liquid diet, enema, and/or laxatives

·  “False-positive” results possible

·  Doctor cannot remove polyps during procedure

·  Positive results may require colonoscopy or other additional procedures

 CT Colonography

 

 “Virtual  Colonoscopy”

·  Doctor can view entire colon and rectum

·  Not invasive, so no risk of bleeding or tearing

·  May not find all polyps or growths

·  Preparation involves thorough cleansing of entire colon through clear liquid diet, enema, and/or laxatives

·  You will be exposed to some radiation (see “Everything You Ever Wanted to Know About Cancer and Radiation but Were Afraid to Ask”)

·  Positive results will require follow-up colonoscopy; recommended immediately after virtual procedure to avoid a second appointment and to biopsy lesions quickly

 

References:

  1. National Cancer Institute. Colorectal cancer PDQ: General information about colorectal cancer. 2009.   Retrieved 22 Feb 2010 from the National Cancer Institute Web Site:  http://www.cancer.gov/cancertopics/pdq/screening/colorectal/Patient/page2
  2. National Institute of Health and National Library of Medicine. 2008. Large intestine. Retrieved on 24 Feb 2010 from the  MedLine Web Site: http://www.nlm.nih.gov/medlineplus/ency/imagepages/19220.htm
  3. Center for Disease Control and Prevention. 2009. Colorectal cancer: Screening saves lives. Retrieved on 23 Feb 2010 from the Center for Disease Control and Prevention Web Site:  http://www.cdc.gov/cancer/colorectal/pdf/SFL_brochure.pdf
  4. Center for Disease Control and Prevention. Colorectal cancer screening rates. 2010. Retrieved on 24 Feb 2010 from the Center for Disease Control and Prevention Web Site: http://www.cdc.gov/cancer/colorectal/statistics/screening_rates.htm
  5. National Cancer Institute. Dictionary of cancer terms: Adenoma. 2009. Retrieved on 24 Feb 2010 from the National Cancer Institute Web Site:  http://www.cancer.gov/dictionary/?CdrID=46217
  6. Zauber AG, Winawer SJ, O’Brien M.J, Lansdorp-Vogelaar I, van Ballegooijen M, Hankey BF, et al.  Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths.  New  England Journal of Medicine.2012; 366(8), 687-696.
  7. United States Preventive Services Task Force. Screening for colorectal cancer. 2008. Retrieved on 18 Feb 2010 from the Agency for Healthcare Research and Quality Web Site:  http://www.ahrq.gov/clinic/uspstf/uspscolo.htm
  8. Center for Disease Control and Prevention. Colorectal cancer screening basic fact sheet. 2009. Retrieved on 23 Feb 2010 from the Center for Disease Control and Prevention Web Site:  http://www.cdc.gov/cancer/colorectal/pdf/Basic_FS_Eng_Color.pdf
  9. Chen, JH and Lin, HH. Colorectal cancer screening. Tzu Chi Medical Journal. 2009; 21 (3), 190-196.
  10. National Cancer Institute. Colorectal cancer screening. 2009. Retrieved on 18 Feb 2010 from the National Cancer Institute Web Site:  http://www.cancer.gov/cancertopics/factsheet/Detection/colorectal-screening
  11. Levi, Z, Rozen, P, Hazazi, R.  A quantitative immunochemical fecal occult blood test for colorectal neoplasia. Annotated Internal Medicine. 2007; 146, 244-255.
  12. Center for Disease Control and Prevention.Colorectal cancer screening tests. 2010. Retrieved on 22 Feb 2010 from the Center for Disease Control and Prevention Web Site: http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm
  13. National Institute of Health. Flexible sigmoidoscopy. 2008. Retrieved on 24 Feb 2010 from the National Digestive Diseases Information Clearinghouse Web Site: http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/
  14. Klabunde, CN, Lanier, D, Nadel, M, McLeod, C, Yuan, G, Vernon, SW. Colorectal cancer screening by primary care physicians: Recommendations and practices 2006-2007. American Journal of Preventive Medicine. 2009; 37 (1), 8-16.
  15. National Institute of Health. Colonoscopy. 2010. Retrieved on 24 Feb 2010 from the National Digestive Diseases Information Clearinghouse Web Site: http://digestive.niddk.nih.gov/ddiseases/pubs/colonoscopy/
  16. Neri, E, Faggioni, L, Cerri, F, Turini, F, Angeli, S, Cini L, Perrone, F, Paolicchi, F, Bartolozze, C.  CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden. Abdominal Imaging. 2009.