Adjuvant Therapy is Effective for Melanoma Patients with a Positive Sentinel Lymph Node Biopsy Who Forego Completion Lymphadenectomy.

Background: Multiple adjuvant therapies for melanoma have been approved since 2015 based on randomized trials demonstrating improvements in recurrence-free survival (RFS) with adjuvant therapy after surgical resection of high-risk disease. Inclusion criteria for these trials required performance of a completion lymph node dissection (CLND) for positive sentinel lymph node (pSLN) disease.
Objective: We aimed to describe current practice for adjuvant therapies in patients with pSLN without CLND (active surveillance [AS]), and to evaluate recurrence in these patients.
Methods: Melanoma patients with pSLN between 2016 and 2019 were identified at two institutions. Demographic information, disease and treatment characteristics, and recurrence details were reviewed retrospectively. Patients were stratified by recurrence and patient-, treatment- and tumor-related characteristics were compared using Fisher's exact test and t test for categorical and continuous variables, respectively.
Results: Overall, 245 SLN biopsies were performed, of which 36 (14.7%) were pSLN. Of 36 pSLN, 4 underwent CLND and 32 underwent AS, of whom 22 (68.8%) received adjuvant therapy with the anti-programmed death-1 (PD1) inhibitor nivolumab (16/22), anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor ipilimumab (3/22), or BRAF/MEK inhibitors (3/22). At a median follow up of 13.3 months, 7/32 (21.9%) patients on AS recurred, including 4/22 (18.2%) who received adjuvant therapy and 3/10 (30.0%) who did not. Tumor ulceration was significantly associated with recurrence. While not significant, acral lentiginous subtype appeared more common among those with recurrence.
Conclusion: The majority (68.8%) of patients with pSLN managed without CLND were treated with adjuvant therapy. The 1-year RFS for patients managed with adjuvant therapy without CLND was 82%, which is similar to modern adjuvant therapy trials requiring CLND.