CHICAGO – The case against performing a complete lymph node dissection in patients with melanoma who have micrometastases in their sentinel lymph node just got stronger in light of findings from a randomized, phase III clinical trial conducted by the German Dermatologic Cooperative Oncology Group (DeCOG).
With 483 patients studied and a median follow-up approaching 3 years, the rate of distant metastasis–free survival did not differ significantly between those who had a complete lymph node dissection and those who had simple watchful waiting, with just 0.3% separating the groups, the investigators reported at the annual meeting of the American Society of Clinical Oncology. Most other key outcomes were likewise statistically indistinguishable between groups.
“This is the first study which tested the general recommendation of complete lymphadenectomy in patients with positive nodes,” senior investigator Dr. Claus Garbe, a professor of dermatology at the University of Tübingen (Germany), said in a press briefing. “We cannot confirm this recommendation, and we expect that the surgical [practice] will change.”
However, Dr. Lynn Schuchter, an ASCO expert, as well as chief of hematology oncology and the C. Willard Robinson Professor of Hematology-Oncology at Penn Medicine in Philadelphia, took a more cautious view, saying that the findings require confirmation before being widely adopted into clinical practice.
“I would say this is a really important study. However, it’s a relatively small study, and I don’t think we would make a complete change in our recommendations yet based upon this study,” she commented.
The ongoing international Multicenter Selective Lymphadenectomy Trial II (MSLT-II), which has a target enrollment of about 1,900 patients and is designed to detect a smaller difference between groups, will provide further information on this issue, according to Dr. Schuchter. “So I think we’ll wait in terms of making definitive changes in our management, for the results of another, larger study with longer follow-up,” she said. “But [the German study] gives us, in that patient who is very concerned about lymphedema ... pertinent information to feel comfortable considering more of a watch-and-wait approach, in terms of monitoring somebody and not doing that surgery.”
Dr. Garbe and colleagues enrolled in their trial patients who underwent resection of a primary cutaneous melanoma of the trunk or extremities at least 1.00 mm in thickness and were determined to have stage III disease with a positive sentinel node containing individual tumor cells or micrometastases. They were randomly assigned to observation only or complete lymph node dissection. Both groups had a lymph node ultrasound exam every 3 months and CT/MRI or PET scans every 6 months.
With a median follow-up of 35 months, patients who had the complete lymph node dissection were about half as likely to develop regional metastases as peers who had watchful waiting (8.3% vs. 14.6%). But the groups did not differ significantly with respect to 3- and 5-year rates of recurrence-free survival, distant metastasis–free survival (the trial’s primary endpoint), and melanoma-specific survival.
The investigators plan to repeat their analysis in 3 years but do not expect the findings will change, according to Dr. Garbe, as the large majority of melanoma recurrences happen in the first 3 years after initial diagnosis.
Dr. Garbe disclosed ties to Amgen, Bristol-Myers Squibb, GlaxoSmithKline, Merck, Novartis, and Roche Pharma AG. The trial was funded by German Cancer Aid.