Amrita Ford, MA, Cancer Prevention and Treatment Fund
Lumpectomy, or partial mastectomy, is the most common surgery for invasive breast cancer. It is performed in 60-75% of new breast cancer cases each year and has been in use for 30 years. Also called breast-conserving surgery, lumpectomy removes the cancerous tumor while preserving as much of the breast as possible. In an attempt to preserve the size of the breast, however, a doctor may accidentally leave behind a small amount of cancer. That’s why almost one in every four lumpectomies is followed by additional surgery, according to a February 2012 study published in the Journal of the American Medical Association.
These repeat surgeries (also known as re-excisions) include women with ductal carcinoma in situ (DCIS), an early noninvasive form of breast cancer that if left untreated can develop into invasive breast cancer.
Experts believe that some women are having additional operations they may not need and others are missing out on surgery that could help prevent a recurrence of breast cancer.
During a lumpectomy, surgeons remove the cancer, along with some surrounding normal breast tissue. They then send the surgically removed tumor and surrounding rim of healthy tissue to a pathology lab. A pathologist will examine the tumor and breast tissue under a microscope, and if no cancer cells are found near the edges of the healthy tissue, it is called a clear margin.
However, surgeons differ widely in their interpretation of the pathology results and disagree on how big of a margin there should be between the cancer and the healthy tissue. This results in re-operation rates for individual surgeons that range from 0 to 70%. Some surgeons consider a lumpectomy successful as long as there is a clear margin between the cancer and normal tissue. Other surgeons prefer a wider margin, sometimes up to 5-10 millimeters, and if there is less, they will operate again. Differences in surgical training or a surgeon’s confidence in removing tumors may explain why surgeons treat margin sizes so differently and why there is a lack of standardization. Rates of repeat surgery also vary from one hospital to another, ranging from 1.7% to 20.9%. That means the number of surgeries a patient will undergo depends in part on her surgeon and the hospital where she receives treatment. The variation between hospitals may be explained by differences in the operating technique of surgeons, or the way in which different pathology teams analyze tissue specimens.
In the study, almost half of the repeat surgeries were done in women with clear but less than 1 millimeter margins, indicating that the surgeries may not have been necessary.
Additional surgeries can be emotionally and physically taxing for patients, as well as an added financial burden. Many women who have repeat surgery subsequently undergo total mastectomy (removal of the entire breast), so the decision to operate again is a significant one. For patients who had a clear margin between tumor cells and healthy tissue, the factors that influenced the decision to operate again were the particular hospital, an unknown cancer diagnosis prior to initial surgery (versus a preoperative diagnosis like invasive ductal carcinoma, for example), and tumor size (very small and very large tumors were more likely to be re-operated).
On the other hand, 14% of patients in the study without clear margins did not undergo an additional surgery, despite being at an increased risk for breast cancer recurrence later on.1 Patients who had evidence of cancer left behind were more likely to be operated on again if their final diagnosis (based on the pathology report after the first surgery) was lobular cancer or if cancer cells were found in their blood or lymphatic vessels. Also, patients who had a lumpectomy based on an unknown cancer diagnosis were more likely to have additional surgery. Other factors may have played a role in the decision not to operate again, such as specific pathological features of the tumor, clinical characteristics of the breast cancer, and the patient’s wishes, but this study did not look at those factors.
The study suggests that whether breast cancer patients undergo repeat surgery following a lumpectomy depends not only on their clinical condition but also on their surgeon and where they receive treatment. While it suggests some patients are having too many surgeries, having a high rate of repeat surgery is not necessarily a bad thing and could mean a surgeon is especially diligent about removing all cancer cells. Similarly, a low re-operation rate could mean the surgeon usually performs lumpectomies correctly the first time, but it could also mean that he or she performs more mastectomies over lumpectomies initially or fails to provide additional surgery when it is needed. 
What Other Studies are Saying
The purpose of additional surgery following a lumpectomy is to reduce the chances of breast cancer recurrence or death from breast cancer. However, the long-term benefits of additional surgery are unclear. Some studies have shown that very small margins (less than 2 millimeters) between the cancerous area and healthy breast tissue lead to an increased risk of recurrence, so a second surgery would be a good idea. [4,5,6] A meta-analysis, which is a combined analysis of several different studies, concluded that wide margins of at least 10 millimeters are important for patients with ductal carcinoma in situ (DCIS) to lower the risk of recurrence. However, other studies have found that larger margins (2 millimeters or greater) don’t reduce recurrence and are, therefore, usually unnecessary. [8,9] Even larger margins (5-10 millimeters) have not been conclusively linked to a reduction in breast cancer recurrence, especially if the patient undergoes radiation or other therapies following surgery to further decrease the chance of recurrence.
Meanwhile, other methods to reduce the number of repeat surgeries are being investigated. Physicians at the University of Michigan Comprehensive Cancer Center were able to reduce the number of repeat surgeries by having an on-site pathologist present in the operating room during lumpectomy surgeries.  The pathologist would examine the tumor and surrounding tissue immediately after their removal and give the results back to the waiting surgeon, who could at that point continue with additional surgery if necessary. Having an on-site pathologist reduced the percentage of patients requiring additional surgery from 25% to 11%. The on-site pathology lab, however, required a different approach for analyzing tumor and tissue samples called frozen section analysis. Frozen section allows samples to be analyzed in a short amount of time and involves freezing the specimen, cutting it, and staining it so it can be viewed under a microscope. The study found that frozen section analysis was just as accurate as traditional methods; however another study found it was slightly less accurate for analyzing the margins of patients with DCIS.  Although the approach increases surgical time for a lumpectomy and requires an investment from the medical center, both time and money will be saved in the long run if women are operated on fewer times.
The Bottom Line
There is no clear evidence whether a second surgery is a good thing for patients because it means the surgeon is being cautious, or a bad thing because women are undergoing two surgeries instead of one. Maybe surgeons could simply ask patients what they would prefer: Would they rather have more of their breast tissue, a bigger “lump,” removed during the first lumpectomy surgery in order to reduce the chance of a second operation, or would they prefer taking out as little breast tissue as possible (preserving the breast’s appearance more), knowing that if the margins aren’t clear, the surgeon will have to perform a second surgery? Judging from the available research, it seems likely that a woman will be more satisfied with the outcome of her lumpectomy if she has a say in whether to remove more or less breast tissue at the initial surgery.
- McCahill LE, Single RM, Aiello Bowles EJ, et al. Variability in reexcision following breast conservation surgery. JAMA. 2012;307(5):467-475.
- Breast Lump Removal. http://www.nlm.nih.gov/medlineplus/ency/article/002918.htm. Accessed February 13, 2012.
- Morrow M, Katz SJ. The challenge of developing quality measures for breast cancer surgery. JAMA. 2012;307(5):509-510.
- Dillon MF, McDermott EW, O’Doherty A, Quinn CM, Hill AD, O’Higgins N. Factors affecting successful breast conservation for ductal carcinoma in situ. Ann Surg Oncol. 2007;14(5):1618-1628.
- Kunos C, Latson L, Overmoyer B, et al. Breast conservation surgery achieving >or=2mm tumor-free margins results in decreased local-regional recurrence rates. Breast J. 2006;12(1):28-36.
- Chan KC, Knox WF, Sinha G, et al. Extent of excision margin width required in breast conserving surgery for ductal carcinoma in situ. Cancer. 2001;91(1):9-16.
- Wang S-Y, et al. Network meta-analysis of margin threshold for women with ductal carcinoma in situ. J Natl Cancer Inst. 2012;507-516.
- Singletary SE. Surgical margins in patients with early-stage breast cancer treated with breast conservation therapy. Am J Surg. 2002;184(5):383-393.
- Houssami N, Macaskill P, Marinovich ML, et al. Meta-analysis of the impact of surgical margins on local recurrence in women with early-stage invasive breast cancer treated with breast-conserving therapy. Eur J Cancer. 2010;46(18):3219-3232.
- Sabel MS, et al. Development of an intraoperative pathology consultation service at a free-standing ambulatory surgical center: clinical and economic impact for patients undergoing breast cancer surgery. Am J Surg. 2011.
- Cendán JC, Coco D, Copeland EM 3rd. Accuracy of intraoperative frozen-section analysis of breast cancer lumpectomy-bed margins. J Am Coll Surg. 2005;201(2):194-198.