Background: The management of patients with resected stage 3 melanoma has changed significantly due to adoption of the Multicenter Selective Lymphadenectomy Trial (MSLT)-2 guidelines and to the survival benefit of adjuvant anti-PD-1 immunotherapy and BRAF/MEK-inhibitor (BRAF/MEKi) therapy. Data are scarce regarding recurrence patterns, adjuvant therapy responses, and therapy-associated adverse events (AEs) in the modern era.
Methods: This single-institution, retrospective study analyzed surgically resected stage 3 and oligometastatic stage 4 patients who received anti-PD-1, BRAF/MEKi, or surgery with active surveillance only. The primary end point of the study was recurrence-free survival (RFS). The secondary end points were the location and clinical characteristics of recurrence and therapy-associated AEs.
Results: From a cohort of 137 patients, the study enrolled 102 patients treated with adjuvant anti-PD-1 (n = 46), adjuvant BRAF/MEKi (n = 3), or surgery alone (n = 26). During a mean follow-up period of 17 months, 20% of the ani-PD-1 patients, 13% of the BRAF/MEKi patients, and 42% of the surgery-only patients experienced recurrence. Log-rank testing showed a significantly longer RFS for the patients treated with anti-PD-1 [15.3 months; interquartile range (IQR), 8.2-23.2 months; p = 0.04] or BRAF/MEKi (17.9 months; IQR, 12.5-23 months; p = 0.01) than for those treated with surgery alone (11.9 months; IQR, 7.0-17.6 months). In the anti-PD-1 group, AEs occurred less frequently than in the BRAF/MEKi group (54% vs 80%; p = 0.03).
Conclusions: Adjuvant anti-PD-1 and BRAF/MEKi were associated with significantly improved RFS for the patients with resected stage 3 or 4 melanoma. The BRAF/MEKi group had significantly more AEs than the anti-PD-1 group. This is the first study to characterize real-world recurrence in the modern era of adjuvant therapy for melanoma.