Category Archives: Medical Treatments with Cancer Risks

Danger at the Dentist’s (and Orthodontist’s) Office: Children Exposed to Radiation

Margaret Aker, Cancer Prevention and Treatment Fund

 


Has your child been to the orthodontist this year? Was he or she exposed to dangerous levels of radiation?

According to research reported in the New York Times,[1] more and more dentists and orthodontists are using an imaging device that delivers significantly higher doses of radiation than regular X-rays. While people usually don’t have any immediate problems from such radiation, exposure can be harmful over the long-term and has been linked to an increased risk of developing cancer.[2]

Promoters of the cone-beam CT scanner claim that this technology is a safe way to obtain highly detailed images of a patient’s mouth and skull that can be used to help treat complicated dental problems more accurately. Health experts, however, are concerned about the cumulative effects of radiation from these scans, and think they shouldn’t be used routinely.

For patients with more serious dental issues, such as cases involving implants or impacted teeth, the scanner’s comprehensive images may justify the radiation exposure. But in most cases, traditional X-rays, which expose patients to far lower levels of radiation, provide perfectly adequate images. It is worrisome, therefore, that some orthodontists, apparently misinformed about the risks of these scans, are using the cone-beam technology to scan all patients-many of whom are children.

The use of the cone-beam CT scanner is even more controversial for children, because they are more susceptible to the effects of radiation than fully developed adults. These scans put children at greatest risk for several reasons: they are smaller, their bodies are still developing, and the earlier they begin getting scanned, the more exposure they are likely to have over their lifetime. The main concern is cumulative exposure, not just a single strong dose of radiation.

In addition to the cone-beam scanner, there is also concern about the safety of X-rays taken during annual visits to the dentist. Despite a national campaign to reduce radiation levels to those absolutely necessary for proper imaging, many dental offices are still using outdated X-ray machines that emit more radiation than the newer machines.  As evidenced by the cone-beam CT scanner, newer does not, of course, always mean less radiation.

Misuse or overuse of the cone-beam CT scanner also points to a much larger issue that has nothing to do with radiation: the extensive financial relationships that exist between doctors and the companies that make medical products. When manufacturers and doctors get too cozy, conflicts of interest arise, and patient care suffers.  The cone beam scanners have become popular, in large part, because the machine’s primary manufacturer, Imaging Sciences International, has paid dentists and orthodontists to promote it. Although these health professionals may endorse the use of this scanner because they truly believe in its benefits, their enthusiasm may be influenced by these payments and the biased information they receive from the companies that make them. After a health professional has received a check, a dinner, or been to a conference at a fancy hotel with all expenses paid, dozens of research studies show that his or her opinion on a given product will probably be more positive than it otherwise would have been.

It is true that each scan only very minimally increases the risk of cancer. Unfortunately, the risk of these scans adds up quickly if every other trip to the orthodontist or dentist requires one. Dentists, orthodontists, patients, and parents need to ask: is this really needed? Especially when the patient is a child and when safer options are available, is the additional exposure to radiation really worth it?

To read more about radiation and how much we are exposed to from the environment, medical imaging and other sources, read our article “Everything you ever wanted to know about radiation, but were afraid to ask.”

References:

[1] Bogdanich W, Craven McGinty J. Radiation Worries for Children in Dentists’ Chair. The New York Times. 22 November 2010.

[2] Gonzalez A. Risk of Cancer from Diagnostic X-rays: Estimates for the UK and 14 Other Countries. The Lancet. 2004;363:345-351.

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 Hormone Therapy: Bad News for Former and Current Smokers

Stephanie Portes-Antoine and Brandel France de Bravo, MPH, Cancer Prevention and Treatment Fund

Because of the risks of breast cancer, stroke, and other serious health problems, experts warn that women should only use hormone replacement therapy if the symptoms of menopause are causing major problems in their quality of life. In those situations, they should use the lowest possible dosage for the shortest period of time.[1] As a result of decreased use of hormone therapy, the breast cancer rate has declined in the United States in recent years. Nevertheless, the combined form of hormone therapy—consisting of estrogen and progestin—is still used by about 15% of postmenopausal women, with more than 25 million prescriptions written every year.[2]

As of June 2009, there is yet another reason to avoid taking hormone therapy. New research shows that hormone therapy can increase a woman’s chance of dying from lung cancer. Lung cancer is the leading cause of cancer deaths in women.

A large government study of post-menopausal women, called the Women’s Health Initiative (WHI), has been the major source of scientific information about the risks of hormone therapy since 2002. A new analysis published in June 2009 found that women who took hormone replacement therapy for five or more years were more likely to die of non-small cell lung cancer than women in the study who did not take hormone therapy.[3] Non-small cell lung cancer accounts for 85% of all lung cancer cases.

There were 16,000 women participating in the WHI study, ages 50 to 79, who either took Prempro, a drug combining estrogen and progestin, or took a placebo. Smoking rates were similar in both groups: half had never smoked, 40% were past smokers, and 10% were current smokers.

The risk of developing lung cancer was similar in both groups, but the women taking the hormones were about 60% more likely to die of lung cancer than the women taking a placebo. Not surprisingly, the risk was highest for current smokers, followed by past smokers, and lowest for never smokers. Among the women who smoked (former or current smokers), 3.4% of those taking hormone therapy died of lung cancer compared to 2.3% for women taking the placebo.

Among women who never smoked, 0.2% of hormone users died from lung cancer, compared with 0.1% of those who got the placebo. While the risk of dying from lung cancer was very small for women who never smoked, almost twice as many women died in the hormone group than in the placebo group. Because of the small number of non-smokers who died from lung cancer in this study, the increase is not statistically significant, which means it could have happened by chance. Research with larger samples is needed to tell us whether even non-smokers are at greater risk of lung cancer if they take hormone therapy.

These findings are consistent with previous research suggesting a link between hormone therapy and non-small cell lung cancer.[4,5] In the Journal of Clinical Oncology in 2006, Dr. Apar Kishor Ganti and his colleagues at the University of Nebraska reported that women with lung cancer who used hormone replacement therapy did not live as long as women who did not use hormones, even though the women receiving hormone therapy were younger.[6] Hormone therapy’s effect on survival was especially pronounced for women with a history of smoking.

According to Dr. Karen Reckamp, assistant professor of medicine at City of Hope Cancer Center in Duarte, California, “We see more and more non-smoking women getting lung cancer in general and often younger women. We know that there are estrogen receptors in the lung and in lung cancers and so there’s definitely an interaction between the development of lung cancer and hormones.”[7] The results from the Women’s Health Initiative study indicate that for most women, the risks of hormone therapy are much higher than the benefits, and we now know this is especially true for women who smoke or used to smoke.

References:

  1. Santoro E., DeSoto M., and Lee JH. Hormone Therapy and Menopause. National Research Center for Women & Families. February 2009. http://center4research.org/medical-care-for-adults/hormone-therapy/menopause-and-hormones/
  2. Smith M. ASCO: Combined Hormone Therapy Linked to Lung Cancer Mortality. MedPage Today. May 31, 2009. http://www.medpagetoday.com/MeetingCoverage/ASCO/14459
  3. Chlebowski RT et al. Non-small cell lung cancer and estrogen plus progestin use in postmenopausal women in the Women’s Health Initiative randomized clinical trial. Journal of Clinical Oncology, 2009 ASCO Annual Meeting Proceedings (Post-Meeting Edition). Vol 27, No 15S (May 20 Supplement), 2009: CRA1500.
  4. Negaard HFS, Eilertsen AL, Anders DA, Iversen PO. Decreased Lung Cancer Survival with Hormone Replacement Therapy: Caused by a Decreased Tissue Factor Pathway Inhibitor Level? Journal of Clinical Oncology. June 10, 2006; 24(7): 2683-2684.
  5. Siegfried JM. Hormone Replacement Therapy and Decreased Lung Cancer Survival. Journal of Clinical Oncology. January 1, 2006; 24(1): 9-10.
  6. Ganti AK, Sahmoun AE, Panwalkar AW, Tendulkar KK, Potti P. Hormone Replacement Therapy is Associated with Decreased Survival in Women in Lung Cancer. Journal of Clinical Oncology. January 1, 2006; 24(1):59-63.
  7. Karen Reckamp, M.D, assistant professor of medicine, thoracic oncology division, City of Hope Cancer Center, Duarte, Calif. May 30, 2009, American Society of Clinical

Heart CT Scans: New Heart Disease Test May Cause Cancer

Julie Bromberg, Cancer Prevention and Treatment Fund

Heart disease is the leading cause of death among adults in the U.S., so some doctors have recently started using Computed Tomography (CT scanning, or “CAT scan”) to detect blockages in the heart’s arteries that can cause heart attacks. Unfortunately, a CT scan uses relatively large doses of radiation-an average heart CT scan exposes a patient to 23 times as much radiation as a chest x-ray.[1,2]

Researchers warn that if this test is widely used, we could see many new cases of cancer from increased exposure to radiation.

Doctors usually decide if a patient has a high or low risk for heart disease by assessing the person’s “risk factors” for heart disease. A “risk factor” is a behavior or characteristic that makes it more likely that a patient will get a certain disease.

People who have a higher risk of heart disease have some of the following risk factors:

  • unhealthy diet,
  • smoke tobacco,
  • high cholesterol,
  • high blood pressure,
  • older age, and several other risk factors

Patients with these high risk factors are more likely to have blocked or narrowed arteries, which can prevent blood flow and are a major cause of heart attacks and strokes. Doctors often recommend medication to people who have a high risk of heart disease, in addition to lifestyle changes such as healthier diet, exercise, and quitting smoking, which can help everyone prevent heart disease.

Even with information about cholesterol and blood pressure, however, doctors cannot always predict who will have blocked arteries. Some people who appear to be at low risk (for instance, non-smokers with low cholesterol) may have a build up in their arteries and could suffer from a heart attack. The heart CT scan has the advantage of detecting blockages in patients who seem to have a low risk of heart disease. One preliminary analysis found that the heart CT scan could prevent 9,000 more deaths than doctors’ traditional way of assessing risk factors while other studies have found that CT scanning does not actually improve health outcomes.[3,4,5]

The American Heart Association, American College of Cardiology, and the United States Preventive Services Task Force do not recommend the use of heart CT scans for patients with a low or high risk of heart disease because CT scans could be more harmful than beneficial due to the relatively high dose of radiation.[6,7]

In contrast, the Screening for Heart Attack Prevention and Education (SHAPE) guidelines recommend that heart CT scans be used to detect blockages in arteries of older men and women who do not have symptoms of heart disease. SHAPE’s guidelines lack scientific support, however, and although well-respected doctors helped write the guidelines, SHAPE is funded by several drug companies that could profit from increased use of heart CT scanning.

If doctors follow SHAPE’s recommendation, tens of millions of adults would be exposed to relatively high levels of radiation through this procedure. Doctors still have not established a standard dose of radiation to be used for heart CT scans and doses for this test vary from one hospital to another, with some patients getting 10 times the amount of radiation as patients in another hospital. A recent study estimated that one heart CT scan for the 50 million Americans who would be affected by SHAPE’s guidelines could cause 2,700-37,000 new cancer cases, depending on the dose of radiation. (Assuming the average radiation dose, these scans could result in 5,600 new cancer cases).[9] The number of new cancer cases could be even higher if individuals were screened more than once in their lifetime.

Radiation from CT scans is of concern to the FDA even when the CT scans are necessary. On October 9, 2009, the FDA announced that it was notifying healthcare professionals that 206 patients who were being tested for stroke received CT radiation doses that were approximately eight times the expected level at one particular medical facility. While this event involved a single kind of diagnostic test at one facility, the FDA warned that “it may reflect more widespread problems with CT quality assurance programs.”

Bottom Line

Each year, over 600,000 Americans die from heart disease even though heart disease can be prevented. Although heart CT scanning may be a useful tool in detecting blockages in heart arteries, there is not enough evidence to show that this test is worth the risks, especially compared to traditional risk factor assessment.[10,11]

For this reason, the Cancer Prevention and Treatment Fund of the National Research Center for Women & Families agrees with the U.S. Preventative Services Task Force that heart CT scans are not recommended for screening for heart disease. And, we agree with the FDA that doctors need to ensure that the risks of radiation from CT scans do not outweigh the benefits of testing.

There are several safer steps you can take to prevent heart disease:

  • Eat healthy foods
  • Exercise
  • Stop smoking
  • Reduce your stress as much as possible

If you have high cholesterol and/or blood pressure, talk to your doctor about how to manage it.

References:

  1. U.S. Department of Energy, Office of Biological and Environmental Research, Office of Science, Ionizing Radiation Dose Ranges. March 2006. Available at: http://lowdose.tricity.wsu.edu/resources_pics/images/026_dose-ranges-sievert.jpg]
  2. Kim KP, Einstein AJ, and de Gonzalez AB. Coronary Artery Calcification Screening: Estimated Radiation Dose and Cancer Risk. Archives of Internal Medicine, July 13, 2009; 169(13): 1188-1194.
  3. Diamond GA and Kaul S. The Things to Come of SHAPE: Cost and Effectiveness of Cardiovascular Prevention. The American Journal of Cardiology, April 2007; 99(7)
  4. Waugh N, Black C, Walker S, McIntyre L, Cummins E, and Hillis G. The Effectiveness and Cost-Effectiveness of Computed Tomography Screening for Coronary Artery Disease: Systematic Review. Health Technology Assessment, 2006; 10(39): iii-iv, ix-x, 1-41.
  5. Gibbons RJ and Gerber TC. Calcium Scoring with Computed Tomography: What is the Radiation Risk? Archives of Internal Medicine, July 13, 2009; 169(13): 1185-1187.
  6. Bluemke DA, Achenbach S, Budoff M, Gerber TC, Gersh B, Hillis LD, Hundley WG, Manning WJ, Printz BF, Stuber M, and Woodard PK. Noninvasive Coronary Artery Imaging Magnetic Resonance Angiography and Multidetector Computed Tomography Angiography: A Scientific Statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young. Circulation, July 2008; 118: 586 – 606.
  7. Barclay L. SHAPE Task Force Recommends Noninvasive Cardiac Screening for Asymptomatic Adults. Medscape Medical News, July 13, 2006.
  8. Kim KP, Einstein AJ, and de Gonzalez AB. Coronary Artery Calcification Screening: Estimated Radiation Dose and Cancer Risk. Archives of Internal Medicine, July 13, 2009; 169(13): 1188-1194.
  9. Kung HC, Hoyert DL, Xu J, and Murphy SL. Deaths: Final Data for 2005. National Vital Statistics Reports. 2008;56(10).
  10. Waugh N, Black C, Walker S, McIntyre L, Cummins E, and Hillis G. The Effectiveness and Cost-Effectiveness of Computed Tomography Screening for Coronary Artery Disease: Systematic Review. Health Technology Assessment, 2006; 10(39): iii-iv, ix-x, 1-41.
  11. Gibbons RJ and Gerber TC. Calcium Scoring with Computed Tomography: What is the Radiation Risk? Archives of Internal Medicine, July 13, 2009; 169(13): 1185-1187.