Breast Cancer Study Shows No Benefit In Extensive Lymph Node Removal
Today’s Times leads with a story on surgical removal of lymph nodes in women with breast cancer. The dramatic digital headline, Lymph Node Study Shakes Pillar of Breast Cancer Care, made me tremble at first glance. The article by Denise Grady covers a new report* in the Journal of the American Medical Association (JAMA).
The key finding is that for women with apparently limited disease before surgery who undergo subsequent radiation and chemotherapy, taking out all the cancerous nodes from the axilla (armpit) has no advantage.
I read the original publication and took some notes:
The randomized study, carried out by the American College of Surgeons, involved 891 women with early-stage breast cancer without palpable lymph nodes in the armpit. All underwent lumpectomy and sentinel lymph node examination that was positive – meaning that pathologists observed malignant cells in a sentinel lymph node. Half of the women underwent complete axillary lymph node dissection, by removal of 10 or more lymph nodes, and half did not undergo removal of additional nodes. All of the patients received radiation therapy and the overwhelming majority (>96%) got chemotherapy. The proportions of women treated with endocrine therapy were similar between the two treatment groups.
What the researchers found was that removing additional glands didn’t improve survival in women who had positive (involved) sentinel nodes upon lumpectomy. Survival was measured at 5 years, and the median follow-up was 6.3 years. There was no difference in overall or disease-free survival. This finding supports that for breast cancer patients who will have 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:
In the majority of BC patients, the lymph nodes in the armpit are not noticeably enlarged at the time of diagnosis. But one in five will have a malignant node detected at surgery. Up until now the standard of care would include a complete axillary lymph node dissection in those women. 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.
According to the Times article, the new research findings could eliminate the need for axillary lymph node dissection in as many as 40,000 women in the U.S. each year: “The discovery turns standard medical practice on its head.”
I’m not so sure I’d go so far as saying that – mainly because I don’t find the results surprising. But I do think it’s a study that matters: The implications bear on costs of breast cancer care (and, yes, on the “costs” of mammography and finding BC) and should have a positive effect on the quality of life for millions of women living after breast cancer treatment. There’s the potential to reduce surgery, and its complications, for the majority of new breast cancer cases.
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 where-ever they reside in the body. The whole point of adjuvant therapy is to destroy malignant cells remaining after surgery. If there are some residual lymph nodes with malignant cells in the armpit region, 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 is the situation for women who undergo mastectomy and don’t get radiation, as is standard after lumpectomy.
Another limitation is the study’s relatively short follow-up, of just over 5 years. This is a valid concern in any study of BC survival, but my own opinion is that the axillary node intervention is unlikely to result in a big difference later on. That’s because in 2011 what matters most for treatment decisions, after diagnosis and initial surgery, is the nature – in terms of genetic and molecular features – of the malignant cells.
It happens the NEJM ran a relevant paper on sentinel node dissection last week; we should explore those findings, tomorrow.