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Rates of Repeat Breast Cancer Surgery Vary Widely

Among women who undergo breast-conserving surgery for invasive breast cancer, the likelihood of having a second surgery varies by institution and by surgeon. These results were published in the Journal of the American Medical Association.

Breast-conserving surgery (also referred to as a lumpectomy or partial mastectomy) is commonly used for the treatment of early-stage breast cancer. It involves removal of the cancer as well as some surrounding normal tissue. The amount of surrounding normal tissue that is removed is referred to as the surgical margin. If the surgical margin is very small, or if cancer is found at the edge of the removed issue (what is referred to as a “positive” margin), additional surgery may be performed in order to ensure that all of the cancer was removed.

To explore the rate of repeat surgery after breast-conserving surgery, researchers collected information about 2,206 breast cancer patients treated at four largeUSinstitutions. All of the women had undergone initial treatment with breast-conserving surgery.

Overall, 23 percent of patients underwent additional breast surgery.
Among women with positive surgical margins, 86 percent underwent additional surgery. Since positive margins increase the risk of cancer recurrence, it’s uncertain why 14 percent of women with positive margins did not undergo additional surgery. There was also notable variability across institutions: the rate of additional surgery among women with positive margins ranged from a low of 74 percent to a high of 94 percent.
Additional surgeries were also performed in women with negative margins, although the benefit of additional surgery in these women is uncertain. The rates of additional surgery were 48 percent when the surgical margin was very small (less than 1.0 mm), 20 percent when the surgical margin was between 1.0 and 1.9 mm, and 6 percent when the surgical margin was between 2.0 and 2.9 mm. And once again, rates of additional surgery varied substantially by institution and by surgeon.

These results highlight the ongoing uncertainty about when additional surgery is necessary after breast-conserving surgery. Different institutions and different surgeons take very different approaches. Research that better defines optimal care—and that encourages more consistent care—could benefit women with early breast cancer.

Reference: McCahill LE, Single RM, Aiello Bowles EJ et al. Variability in reexcision following breast conservation surgery. JAMA. 2012:307:467-475.