With all the progress made in cancer surgery over the past several decades, one practice has remained largely unchanged — until now. For more than a century, women with breast cancer that has spread beyond the breast have been undergoing a potentially debilitating and painful procedure in which all the lymph nodes in the armpit are removed.
Now a multicenter study of which Monica Morrow, Chief of Memorial Sloan Kettering's Breast Service in the Department of Surgery, was the senior author has found that for women who meet certain criteria — about 20 percent of all breast cancer patients — the surgery, called axillary node dissection, is unnecessary and does not improve survival or reduce rates of recurrence.
The findings apply to women who have tumors that are less than 5 centimeters in size, have clinically negative lymph nodes (meaning that no enlarged nodes can be felt during a physical exam), are treated with lumpectomy followed by whole-breast radiation therapy, and have cancer in fewer than three sentinel nodes (the first lymph nodes to which cancer spreads when it leaves the site of origin). The majority of women in the trial also had chemotherapy and/or hormone therapy such as tamoxifen, which is part of the standard treatment for breast cancer if there is any lymph node involvement.
“When axillary node dissection was developed more than 100 years ago, it was the only tool we had,” Dr. Morrow explains. “Now these patients are getting treatment with radiation that treats part of their armpit and with drug therapy that also helps kill cancer cells. It's only logical that when you add in other effective therapies, you are able to decrease the amount of surgery that you're doing.” The new recommendations do not apply to women with the earliest stage of disease and no lymph node involvement, who normally would not undergo lymph node removal anyway, or to women whose disease has already spread to other parts of the body.
The study, which was published in February in the Journal of the American Medical Association, randomized 446 patients to undergo axillary lymph node dissection and 445 to have no further surgery after lumpectomy and sentinel node biopsy. [PubMed Abstract] The five-year overall survival was 91.8 percent in women who underwent the additional surgery versus 92.5 percent in women who did not. The five-year disease-free survival rate (the number of women who didn't have their disease return) was 82.2 percent in patients who had axillary node dissection versus 83.9 percent in those who didn't have it.
Avoiding removal of all their armpit lymph nodes allows women to steer clear of the often-severe side effects that are associated with that procedure. The most common is lymphedema, or swelling of the arm, which can be permanent and can greatly affect quality of life. The surgery also can lead to temporary or permanent loss of arm strength and movement and is associated with a longer and more painful recovery after surgery. Changing the standard treatment will allow up to 40,000 women in the United States each year to avoid these side effects.
Dr. Morrow and the other researchers on the study, which was conducted under the auspices of the American College of Surgeons Oncology Group, a clinical trials group funded by the National Cancer Institute, say that the study should be practice changing. How quickly the new recommendations will be adopted, however, is not clear. “When breast-conserving surgery first became available, the change from mastectomy happened very slowly,” Dr. Morrow explains.
“It's interesting that as a community we've always been enthusiastic about adding more treatments,” she adds. “But when we talk about decreasing treatment, which is what this study is about, people tend to get uncomfortable. It remains to be seen how quickly this new standard will be adopted. However, in our experience here at the Center so far, patient acceptance has been great.”
The average time the patients in the trial were followed after surgery was 6.3 years, and investigators are continuing to follow the study participants. “Long-term outcomes are of interest because we know it's a disease that recurs beyond five years, at least in other parts of the body,” Dr. Morrow notes. “Having said that, we know that most recurrences in lymph nodes tend to happen within the first five years, so we don't expect that our findings are going to change.”