M1 - Current Adjuvant Therapy Use in the Setting of Sentinel Node Positivity for Melanoma

Intro: Adjuvant therapy in melanoma was approved based on trials requiring complete resection of disease, particularly completion lymph node dissection (CLND) in stage III disease. Specifically, in Checkmate 238 the 12-month recurrence free survival was 72.3% in the nivolumab group for Stage IIIB and IIIC resected patients. As CLND is no longer standard following positive sentinel lymph node biopsy (SLNB), we aim to describe use of adjuvant therapy in patients with positive SLNB without CLND, and evaluate factors associated with recurrence.

Methods: Melanoma patients undergoing SLNB after 2016 were identified at two institutions. Demographic information, disease and treatment characteristics and oncologic outcomes were reviewed retrospectively. The primary outcome was recurrence, assessed by Wilcoxon-rank sum and Pearson’s chi-squared tests for continuous and categorical variables respectively.

Results: 243 SLNB were performed, of which 34 (14.0%) were positive for metastatic disease (pSLN). Of 34 pSLN, 4 underwent CLND and 30 underwent active surveillance, of which 21 (70.0%) received adjuvant therapy with anti-PD1 (15/21), anti-CLTA4 (3/21) or BRAF/MEK (3/21). At a median follow up of 1.1 years, 7/29 (24.1%) patients on surveillance with follow up data available recurred (4/21 [19.0%] on adjuvant, 3/8 [37.5%] not receiving adjuvant). Factors associated with recurrence, though likely not statistically significant due to small sample size, included acral lentiginous subtype, presence of ulceration and lack of receipt of adjuvant therapy.

Conclusion: The majority of patients with sentinel node positivity and no CLND were treated with adjuvant therapy, with a recurrence rate similar to clinical trials requiring CLND.