Real-world clinical outcome and safety of adjuvant therapy in stage III melanoma patients: Data from two Academic Italian Institutions

: Adjuvant immunotherapy (IO) and targeted therapy (TT) have improved relapse-free survival (RFS) in patients with stage III melanoma, although about 25% of them relapse within a year. However, real-world data on treatment efficacy and safety as well as management of treatment recurrences are still limited. We retrospectively analyzed 113 patients with stage III melanoma who received at least one cycle of anti-PD-1 (nivolumab or pembrolizumab) or dabrafenib + trametinib as adjuvant therapy. Most of patients included into the analyses harbor BRAV600E mutation (66.4%) and had a stage IIIC melanoma (63.7%). Immunotherapy was administered in 48.7% of patients, whereas targeted therapy in 51.3% At data cut-off, median RFS was not reached with 12- and 24-months RFS of 81% and 64%, respectively. No new adverse events were registered. Thirty patients (26.5%) relapsed, mainly at distant sites. Patient treated with IO recurred mostly during adjuvant treatment (ON-treatment) while patients treated with TT relapsed at the end of treatment (OFF-treatment). At relapse, surgery, radiotherapy and systemic therapy were used alone or in combination. Among patients who started a first-line therapy, an excellent response switching to a different treatment was observed. Real-world outcomes and safety of adjuvant treatment for resected stage III melanoma appear comparable to clinical trials data. Moreover, management of recurrences depends on type of relapse (loco-regional vs distant) and timing (during vs OFF treatment). Furthermore, patients who relapse after adjuvant TT respond well to subsequent anti-PD1 based therapy.