Sometimes less is more in breast cancer treatment; so says a study that made headlines earlier this month: The finding, published in the Journal of the American Medical Assn., reported that surgically removing multiple cancer-containing lymph nodes under the arm in women with small tumors — instead of just one or two — may cause more harm than good.
The finding seems to fly in the face of what most people believe — that cancers must be treated aggressively for the best odds of recovery and survival.
But, in fact, many breast cancer surgeons say the study puts solid evidence on what was already becoming a trend in practice — moving away from the more radical surgery in certain patients. "It's not a revolution, it's an evolution," says Dr. John Glaspy, an oncologist at UCLA's Jonsson Comprehensive Cancer Center.
It's still unclear whether the advice from the study will be broadly accepted as the new standard of care — and how long that will take.
"Many changes in medicine — believe it or not — take 17 years to take hold," wrote Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, on his blog after the JAMA report came out.
Here's a look at the pros and cons of removing underarm lymph nodes in breast cancer and who will be affected.
The study subjects were women with breast tumors up to two inches across and evidence of cancer cells invading at least one nearby lymph node but not more than two, as determined by a procedure called sentinel lymph node biopsy. In this procedure, a dye is injected near the tumor and the first lymph nodes to which the dye travels are removed and biopsied for cancer cells.
All 891 patients received lumpectomy and radiation therapy, and a majority of them also underwent chemotherapy. In addition to the one or two sentinel lymph nodes removed for diagnosis of invasive disease, one group of women also underwent what surgeons call axillary lymph node dissection, which means surgical removal of at least 10 lymph nodes from under the arm.
Survival rates were statistically similar in the two groups, with more than 90% of women surviving and more than 80% remaining disease-free for five years after treatment.
These findings suggest that removing a bunch of lymph nodes from under the arm doesn't make a difference in the long-term prognosis of breast cancer patients. Doctors say this makes sense, because there are many paths by which cancer can escape the breast and spread.
"We used to think cancer made a straightforward progression from breast to lymph nodes to other places in the body," says Dr. Grant Carlson, a surgeon at Emory University's Winship Cancer Institute in Atlanta. It's now clear that cancer can move to other parts of the body without necessarily setting up shop in the lymph nodes.
In fact, by the time cancer is detectable in the lymph nodes, cells have probably been getting into the lymph and the blood stream for a while, Glaspy says. Merely removing the evidence of invasion from one place, the underarm lymph nodes, is akin to "clearing the drain trap," he adds, but does not improve the cure rate. "You can't cure metastatic disease with a scalpel," he says.
The radiation therapy used in the study may have neutralized cancers growing in the lymph nodes, experts say. It may be a critical component of care for women with similar cancers to those in the study — that is, small tumors and some evidence that the disease has spread.
Radiation therapy has improved "tremendously" over the past couple of decades, Glaspy says. "We're much better at delivering therapeutic doses with less toxicity."
Another factor tipping the scales away from surgery is the risks associated with surgery. A major complication of axillary lymph node dissection is a persistent and incurable swelling in the hand and arm, called lymphedema. The incidence and severity of lymphedema have decreased as breast cancer surgeons have become more skilled and as fewer lymph nodes are removed these days — 10 to 15 compared with 20 to 30 a couple of decades ago.
Current rates of lymphedema are about 15% in women who have had underarm lymph nodes surgically removed, Carlson says. Elephant-sized arms are rare these days, but the hand may still swell to a point where rings can't be worn and compression sleeves are necessary during air travel.
Women who had axillary lymph node dissection also must take extra care to avoid cuts and infection. "They have to be careful with certain activities, such as gardening," Carlson says.
Experts say the findings from the new study don't apply to women with more advanced cancers or with cancerous lymph nodes that are palpable (lumps that you can feel) or when radiation is not part of the treatment plan.
And some think that surgical removal of multiple lymph nodes may reduce the risk of cancer recurring under the arm; while no difference in recurrence rates was detected in the study, it wasn't long enough or large enough to answer that question for sure, Glaspy says.
Still, he adds, the evidence is compelling for the most important endpoint — survival — and the findings finally give doctors clear numbers on possible outcomes to present to patients when deciding on breast-cancer treatments. "It will allow evidence-based discussion between women and their doctors — not just 'If you were my wife' advice," Glaspy says.