A new report in the Journal of the American Medical Association may influence -- and reduce -- surgical treatment for many women diagnosed with breast cancer. The key finding is that for women with apparently limited disease before lumpectomy and what's called a positive sentinel node, taking out all the cancerous nodes from the axilla (armpit) has no survival advantage after five years.
I've reviewed the study in more detail, elsewhere. It's got a lot of strengths: it's randomized, Phase III and multi-institutional -- meaning that the trial was carried out by many surgeons caring for patients at a variety of medical centers. In total, 891 women were enrolled, all of whom had clinically small tumors and a positive sentinel node. Half of the patients underwent complete axillary lymph node dissection; the others did not. Nearly all got chemotherapy; some received endocrine treatments.
What the researchers found is that removing additional glands didn't improve survival in women who had positive (involved) sentinel nodes upon lumpectomy. This finding supports that for breast cancer patients with small tumors who will undergo radiation and chemotherapy, it's OK for surgeons to leave malignant lymph nodes in place rather than remove those by more aggressive surgery.
Why this matters:
For women with apparently limited (stage I or II) breast cancer at the time of diagnosis, approximately 20 percent will turn to have a positive lymph node. Up until now, the usual care of those patients has included a complete axillary lymph node dissection. During that part of surgery, typically 10 to 25 lymph nodes are removed. This procedure can lead to lymphedema, a condition of chronic arm and hand swelling that can be painful and disabling.
Lymphedema affects a small but significant fraction of the growing ranks of women --approaching 3 million in the U.S. -- who are alive after breast cancer treatment. So if the axillary lymph node dissection can be eliminated from the standard breast cancer surgery process, that would spare a lot of women from an uncomfortable, compromising situation.
The implications bear on costs and risks of breast cancer care, apart from the lymphedema effects. There would be less time in the O.R. and reduced costs of pathology (think of examining one lymph node instead of 20 in 100,000 to 200,000 surgeries per year in the U.S.). There'd be less time under anesthesia. With fewer lymph nodes removed, the risk of infection in a woman's hand or arm diminishes.
An irresistible aside to this story is that the findings should lessen the "costs" side of any mammography equation: With the application of these results, expenses and potential complications of breast cancer treatment will be reduced.
Why aren't the results surprising?
Breast cancer treatment, and our understanding of breast cancer biology, has advanced steadily in the past 25 years. Now it's routine to give treatments -- like chemotherapy, hormone modulators or antibodies like Herceptin -- that target breast cancer cells wherever they reside in the body. The whole point of adjuvant therapy is to destroy malignant cells remaining after surgery. If there are residual lymph nodes with malignant cells in the armpit region after surgery, those would likely be destroyed by chemotherapy and other treatments, combined with radiation to the affected chest and underarm area.
What are the study's limitations?
What's not adequately addressed in the paper and editorial, I think, is the situation of women who undergo mastectomy and don't get radiation to the region, as is standard after lumpectomy. As much as I'm drawn to the "less is more" approach to cancer therapy, I don't know that we can extrapolate these data to the circumstances of women who don't get radiation.
Another limitation is the study's relatively short follow-up of just over five years. This is a valid concern in any study of breast cancer survival, but my own opinion is that the axillary node intervention is unlikely to result in a big difference later. That's because in 2011 what matters most for treatment decisions in breast cancer, after diagnosis and initial surgery, is the nature -- in terms of genetic and molecular features -- of the malignant cells.
General implications:
When I studied oncology, the dogma was that the prognosis in breast cancer rests on the size of the tumor and the number of lymph nodes involved. But that was 20 years ago. Now we know that tumor markers -- if the cells express estrogen or progesterone receptors, HER2, as well as other factors including genetic mutations that affect the malignant cells's aggressiveness and responsiveness to treatment -- are at least as important in determining outcome. So although some physicians will express concern that we need the full lymph node pathology results to establish the prognosis and formulate treatment recommendations, I think in 2011 we can do better using molecular, modern predictors of disease responsiveness.
Finally, there's a suggestion in some of the coverage that doctors and patients may have a hard time accepting "less" as better treatment for this disease. I don't really think that's the case anymore, at least not for patients. From my experiences as an oncologist, as a breast cancer patient and knowing so many women who've undergone debilitating treatments, I expect most patients will accept this development as progress and a sound reason to avoid extra surgery. It may be the physicians who need be persuaded that taking out all the lymph nodes does not improve a breast cancer patient's prognosis.
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Removing the nodes is only used as a staging procedure, not a therapeutic procedure. Now that there are more precise tumor biology tests for staging, taking the nodes to stage has become obsolete with a high side effect profile. As far as the current article applying to four out of ten women, that is only because that is the subset of women the study looked at. If you read the previous medical literature you will see the ineffectiveness of removing the nodes applies to all categories of breast cancer patients.