Data from a new study indicate a lack of therapeutic benefit for therapeutic lymph node dissection for patients with lymph node recurrences in melanoma. The study was presented at the 2020 annual meeting of the Society of Surgical Oncology (abstract 79).

According to Ana Wilson, MS, DO, a second-year fellow at John Wayne Cancer Institute, in Santa Monica, Calif., who presented the data, approximately 10% to 15% of patients with melanoma who had negative sentinel lymph node biopsies at their index operation will experience a locoregional recurrence, and 4% to 10% of patients will develop an isolated lymph node recurrence in the same basin, depending partly on the experience of the surgeon.

“The majority of these recurrences happen in the first two years after surgery and are more common in patients with thicker, ulcerated primary lesions; lesions on the trunk, head or neck; and in patients who are male,” Dr. Wilson said.

Although completion lymphadenectomy is no longer recommended for patients with melanoma and tumor-positive sentinel lymph nodes, therapeutic lymph node dissection is still recommended for patients with melanoma and lymph node recurrences, Dr. Wilson said. The new study investigated the potential survival benefit of therapeutic lymph node dissection in patients with nodal recurrence after a previously negative sentinel lymph node dissection.

The researchers used the John Wayne Cancer Institute’s melanoma database of over 15,000 patients and data from the MSLT-1 (Multicenter Selective Lymphadenectomy Trial), to identify patients with nodal recurrences after a negative sentinel lymph node biopsy. Patients with concomitant local or distant recurrence were excludded. The investigators compared patients who underwent therapeutic lymph node dissection with those who underwent biopsy alone, focusing on differences in clinicopathologic characteristics, distant metastasis–free survival and melanoma-specific survival between the groups.

The investigators identified 172 patients with lymph node recurrence in a previously negative sentinel lymph node basin during the study period (1991-2017). Median follow-up was 30 months from the time of recurrence. Therapeutic lymph node dissection was performed in 78% of patients, and 22% were treated with lymph node biopsy alone. Five-year distant metastasis–free survival was 50.4% for patients who had a biopsy alone compared with only 39.4% for those having therapeutic lymph node dissection (P=0.13). Overall, five-year melanoma-specific survival was 59.4% in the biopsy group and 45.9% in the therapeutic lymph node dissection group (P=0.10). In the therapeutic lymph node dissection group, 40.3% had one tumor-positive lymph node and 59.7% had two or more. For both subgroups, melanoma-specific survival was lower than the biopsy-alone group (52.8% and 41.2%, respectively; P=0.07). There was no significant difference in use of systemic treatment or immunotherapy between the groups.

“Therapeutic lymph node dissection did not improve survival in this retrospective study of patients with nodal recurrence of melanoma,” Dr. Wilson said, noting that there was a trend toward worse outcomes after therapeutic lymph node dissection. “Although the survival appears better in the biopsy-only group, the cohort is too small and varied for this to be statistically significant,” she said.

According to Dr. Wilson, presumably, at least some patients in the biopsy-alone group had multiple involved lymph nodes, yet they still had at least equivalent outcomes to patients with one positive node treated with therapeutic lymph node dissection.

“At face value, these were somewhat unexpected findings,” said Sandra Wong, MD, a melanoma expert and the William N. and Bessie Allyn Professor of Surgery and chair of the Department of Surgery at Dartmouth-Hitchcock in Lebanon, N.H., and the Geisel School of Medicine at Dartmouth, in Hanover, N.H.

“But, one important consideration is that there is no therapeutic benefit to removing negative nodes. If the patients in the biopsy-alone group had all disease cleared with that biopsy, then there was 1) a relatively low burden of disease (likely one involved node) and 2) likely enough therapeutic benefit from the biopsy alone to explain some of the distant metastasis–free survival and melanoma-specific survival results that were presented,” Dr. Wong said.