Many women with early breast cancer don’t always to have their lymph nodes removed, as is often recommended. The federally funded study, involving nearly 900 women who were treated at 115 sites across the country, found that those who kept their lymph nodes were no less likely to survive five years after the surgery than those who did not, the researchers reported in the Journal of the American Medical Association.  Breast cancer is diagnosed in about 200,000 women each year in the United States, with the cancer reaching the lymph nodes in about 33 percent of the cases.

The study’s finding turns a century of standard medical practice on its head.  According to Dr. Armando E. Giuliano, the lead author and chief of surgical oncology at the John Wayne Cancer Institute at St. John’s Health Center in Santa Monica, CA, approximately two-thirds of these women will match the study criteria and one-third will not. For that one-third — about 10 percent of breast cancer patients overall — node removal might be needed.  An additional five percent of all patients have “distant” disease at the time of diagnosis, meaning the cancer has already spread to organs or bones.  In the remaining two percent of cases, the stage of the disease at diagnosis is not known. There is still a risk of lymphedema even after only a few nodes are taken for biopsy, but the risk is significantly reduced than when multiple nodes are removed.

Dr. Monica Morrow, an author of the study and chief of the breast service at Memorial Sloan-Kettering Cancer Center in New York said that “Genetic breast cancer doesn’t influence how we treat the nodes.  Due to the increased risk of second breast cancers, many of these women chose mastectomy.  Women with mastectomy require axillary dissection if the nodes are involved.”

“Removing all of the lymph nodes under the arm is, first of all, for many women a second trip to the operating room” said Dr. Elisa Port, Mount Sinai Medical Center’s chief of breast surgery.  “And secondly, there’s a lot of side effects associated with removing all of the lymph nodes under the arm.  There’s a higher risk of developing what we call lymphedema, which is swelling of the arm.  There is some numbness on the inner part of the arm that you can get from cutting through the little nerves that run near the lymph nodes, and some women even have mobility issues.  So sparing them this bigger surgery is certainly significant for a large number of women.”

Professor Robert Mansel, professor of surgery at University of Wales College of Medicine, Cardiff, an expert in breast cancer research, said the study is very controversial with a lot of practice “based on feelings, not data.” Mansel currently favors lymph node removal, believing the research on leaving them intact is so far inconclusive.   He urged caution about the study, pointing to “lots of warning signs,” such as failure to include as many women in the study as they would have liked – meaning the trial was “under powered”.  When faced with the prospect of lymph nodes not being removed, many patients chose not to enter the trial, he said.  He also pointed to the study’s five-year follow-up, which he believes is too short.  “Breast cancer, if nothing else, is a long-term disease, which makes this study only half way to being reliable.”

Mt. Sinai’s Dr. Port acknowledges that not all breast surgeons will agree with the new study.  “But there is no question that for many people the results that you don’t have to remove cancer are very counterintuitive and go against the sensibility of what we, as surgeons, have been ingrained to do, which is remove cancer.  And the more cancer you can remove, the better.  Doctors are supposed to do what they know to be the safest thing, and many of us erred on the side of caution, which is to take out those lymph nodes to make sure we weren’t missing anything.”