Surgically removing lymph nodes does not improve survival for certain patients with melanoma. The results from the large phase III randomized Dermatologic Cooperative Oncology Group Trial (abstract LBA9002) were presented at the 2015 American Society of Clinical Oncology (ASCO) Annual Meeting held May 29 to June 2 in Chicago.
A complete lymph node dissection (CLND) may not be necessary for patients with micrometastatic cutaneous melanoma following a positive sentinel lymph node biopsy (SLNB). Patients with detectable metastatic tumors were not part of this study.
After a 1-year follow-up period, patients who had a CLND did not have a survival advantage compared with those who did not undergo a CLND. The patients will continue to be followed for another 3 years after which survival will again be assessed.
These findings may allow some melanoma patients to forego CLND, an intensive surgery that can result in significant morbidities such as lymphedema, numbness, and tingling. Lymphedema is a particularly hampering side effect that affects as many as 20% of patients and can persist long term in about 10% of patients.
CLND has been a standard part of melanoma surgery around the world for those with positive lymph nodes, as these patients are presumed to be at an increased risk for recurrence and emergence of metastasis.
Claus Garbe, MD, a professor of dermato-oncology at the University of Tübingen in Germany, and study coauthors randomized 483 patients 1:1 to either observation only or CLND between 2006 and 2014.
After a mean follow-up of 35 months, 14.6% of patients in the observation arm and 8.3% of patients in the CLND arm developed regional lymph node metastases close to the primary tumor. Still, there was no significant difference in the 5-year disease recurrence–free survival (P = .72), distant metastases–free survival (P = .76), or melanoma-free survival (P = .86). A difference of 10% or more was deemed statistically significant, according to the design of the trial.
“Today, we do not know which patients are already cured by their sentinel node biopsy procedure, which ones are destined to die no matter what surgery is done, and which ones might be saved from recurring and dying—or at least from extra surgical side effects—by early use of lymph node dissection,” said Vernon Sondak, MD, chair of the department of cutaneous oncology at the Moffitt Cancer Center & Research Institute in Tampa, Florida, who was not involved in the study. “Randomized trials like this one and the much larger Multicenter Selective Lymphadenectomy Trial II (MSLT-II) will help answer these important questions over the next few years.” MSLT-II is currently addressing the same question about CLND; the study results are not expected until 2022.
According to Sondak, a potential improvement in survival is only one reason that a patient could be recommended to undergo a CLND. The main reason is the chance of a local lymph node recurrence that would later require more difficult surgery.
The study’s follow-up of 35 months, however, is not long enough to assess the long-term impact of lymph node surgery for stage III melanoma patients. “Many patients who don’t have a sentinel node biopsy don’t have positive nodes show up as a palpable lump until 3 or more years later,” said Sondak. He added that it could take 10 years or more for nodal disease to recur.
“We are going to need to be patient and let a lot more time go by before we can make final conclusions,” he said. “For now, this information provides a degree of reassurance to those patients who went onto randomized trials such as this and MSLT-II that delaying lymph node surgery after a positive sentinel node is not harmful in the short run.”