Lymph Node Test Helps Fight Melanoma
'Sentinel' nodes help doctors spot the cancer's spread
WEDNESDAY, Sept. 27, 2006 (HealthDay News) -- Using so-called "sentinel node" biopsies to determine if melanoma has started to spread saves some patients the pain of having all their lymph nodes removed, U.S. researchers report.
The strategy can also give patients a jump-start on aggressive treatment, they added.
There are few treatment options for melanoma unless the disease is caught early. As a result, melanoma is one of the deadliest cancers around.
However, patients whose lymph nodes tested positive for cancer, and who had all their lymph nodes removed, had a much higher five-year survival rate compared to those who tested positive but delayed node removal.
These results should help make sentinel node biopsy standard practice in dealing with this type of malignancy, said lead researcher Dr. Donald L. Morton, medical director and chief of the melanoma program at John Wayne Cancer Institute at Saint Johns Hospital in Santa Monica, Calif.
His team published its findings in the Sept. 28 issue of the New England Journal of Medicine.
"People had been skeptical that sentinel node biopsy was necessary. This further cements the view that it is," said Dr. Vijay Trisal, an assistant professor of surgical oncology at City of Hope Cancer Center in Duarte, Calif. "This gives us an idea about the biology of the cancer, and gives us ammunition that this is the right thing to do."
The findings are "not earth-shattering in the sense of treatment, but certainly in terms of prediction," commented Dr. Donald McCain, a surgical oncologist and member of the melanoma division at Hackensack University Medical Center Cancer Center, in Hackensack, N.J.
Melanoma is the most rapidly increasing malignancy in the world today. According to the American Cancer Society, nearly 60,000 Americans will be diagnosed with melanoma this year, and almost 8,000 will die from the disease.
About 20 percent of patients with melanomas of intermediate thickness have a microscopic spread of their cancer to the lymph nodes -- meaning the metastasis can't be seen or felt. Generally speaking, melanoma that spreads to the lymph nodes has a much poorer prognosis.
Still, physicians haven't been sure how to approach the issue. Experts have tended to split into two camps: one recommending that all lymph nodes automatically be removed, and the other advocating waiting until the mass can actually be felt in the lymph nodes.
"The problem with [the first] approach is that since only 20 percent of patients have nodal metastasis, the other 80 percent have an operation that they can't benefit from. They don't really need it," Morton explained. "The question is how to figure who does and who doesn't need it."
Enter sentinel node biopsy, a technique developed by Morton and colleagues about 20 years ago. Here, the surgeon tests only one or two lymph nodes, where the cancer is most likely to head to first. If these are positive, the rest of the lymph nodes are tested and removed. If not, the patient is left alone.
"We found that about 20 percent of people of this intermediate thickness would have spread to one to two sentinel nodes," Morton said.
This trial, which an accompanying editorial called the "largest and most important trial of sentinel-lymph-node biopsy for melanoma conducted to date," sought to determine if sentinel node biopsy made any difference in survival.
Investigators randomly assigned 1,269 patients with intermediate thickness melanoma (1.2 to 3.5 millimeters) to have a sentinel node biopsy (followed by removal of lymph nodes if they contained cancer) or simply observation. If participants in the observation-only group developed a palpable mass in their lymph area, they also underwent removal of all lymph nodes.
Five-year, disease-free survival was similar in both groups: 78.3 percent in the biopsy group and 73.1 percent in the observation group.
The difference was in patients with cancer-positive vs. negative lymph nodes. Patients whose sentinel nodes were tumor-negative had a five-year survival rate of 90.2 percent whereas those with tumor-positive sentinel nodes had a survival rate of only 72.3 percent.
And for those patients with positive lymph nodes, the five-year survival rate was higher among those who immediately had all their lymph nodes removed (72.3 percent) vs. those who delayed removal (52.4 percent).
"As far as I'm aware, outside of this trial there's never been any randomized trial that showed a survival benefit for melanoma with sentinel node biopsy," Morton said.
The technique is used routinely by doctors for breast, lung and colon cancers. "It is a universal principle that in cancers that spread through the lymphatics, if it's going to spread, it'll be in the sentinel node," Morton said. "Sentinel node biopsy saves two-thirds of women a radical actuary dissection."
As for melanoma, experts now know there is a survival benefit there, as well. "Those with positive sentinel lymph nodes had worse survival than those who didn't," McCain said. "This separates out those you could treat aggressively vs. those you could leave alone."
To learn more about melanoma, visit the American Cancer Society.