By Alan Mozes
This invasive procedure -- called complete lymph node dissection -- is a standard but hotly debated treatment for melanoma, the deadliest type of skin cancer.
For the study, investigators tracked more than 1,900 melanoma patients around the world. They found that complete lymph node removal was no better than less extensive surgery and observation for extending survival.
"I think many more patients will decide to go with observation now, rather than immediate complete lymph node dissection," said study author Dr. Mark Faries.
The findings may help clear up decades of debate regarding how best to employ lymph node removals, said Faries, co-director of the melanoma program at Angeles Clinic and Research Institute in Los Angeles.
A New York City cancer specialist agreed the study results could change standard practice.
The findings are a "game-changer" that will protect patients from the debilitating consequences of unnecessary surgery, said Dr. Daniel Coit, an oncology surgeon at Memorial Sloan Kettering Cancer Center in New York City.
The more extensive surgery comes with complication risks, including post-op lymphedema. This is a significant quality-of-life impairment in which a patient's arm or leg swells with fluid after the normal lymphatic pathway is disturbed.
This new study clearly defines the proper role of surgery, Coit said. "I think that this is an absolute definitive statement on the question," he added.
(Lymph nodes are glands that are part of the body's lymph system, a key component of the immune system.)
Roughly half underwent extensive lymph node surgery to remove the sentinel node and adjacent lymph nodes.
But, the remaining patients only underwent minimally invasive sentinel node removal, leaving all surrounding nodes in place for further observation.
The research team found that removing all the lymph nodes did help doctors get more detail on a patient's long-term prospects. Doing so also appeared to extend the period of time patients remained disease-free.
But, in the end, "the study showed that the additional surgery did not improve a patient's chance of living longer," said Faries.
The results were published in the June 8 issue of the New England Journal of Medicine.
Rates of melanoma have been rising for 30 years. According to the American Cancer Society, more than 87,000 new melanomas will be diagnosed in the United States this year, and close to 10,000 Americans will die from it.
Faries noted that elective removal of lymph nodes was first advocated as a treatment option at the end of the 19th century.
The reason, he said, is that about 20 percent of "intermediate-risk melanoma" patients have cancer in lymph nodes that goes under the radar unless removed and examined.
But in the 1980s, researchers identified the tell-tale sentinel node, enabling less invasive biopsy. And many doctors moved away from full lymph node removal in cases where the sentinel node was found to be cancer-free.
"If the sentinel node is clear, the other nodes in that area should be clear as well," explained Faries.
However, in cases where a sentinel node is cancerous, full lymph node removal surgery is still the standard, despite debate as to whether it's of significant benefit.
To explore that question, investigators tracked melanoma patients from 60 medical facilities between 2004 and 2014.
Among those who had all their lymph nodes removed, nearly one-quarter developed lymphedema.
But among those who only had their sentinel node removed, just 6 percent developed such swelling, while survival rates remained comparable.
Coit, author of an editorial that accompanied the study, said it's reasonable to say that 30 percent of patients who undergo full removal are at risk of lymphedema. That goes up to 50 to 60 percent among older and overweight patients, he added.
"Breast cancer is a very different cancer, but they've already established pretty much the same thing with that disease," Coit said. "And this finding is completely consistent with the results of a previously published, smaller trial."