Adjuvant Treatment of In-Transit Melanoma: Narrowing the Knowledge Gap Left by Clinical Trials.

Few clinical trials address efficacy of adjuvant systemic treatment in patients with in-transit melanoma (ITM). This study describes adjuvant systemic therapy of ITM patients beyond clinical trials. In this study we included stage III adjuvant-treated melanoma patients registered in the nationwide Dutch Melanoma Treatment Registry between July 2018-December 2020 were included. Patients were divided into three groups: nodal disease only, ITM only, and ITM and nodal disease. Recurrence patterns, recurrence-free survival (RFS), and overall survival (OS) at 12-months were analysed. In our study population of 1037 patients, 66.8% had nodal disease only, 16.7% had ITM only, and 16.2% had ITM with nodal disease. RFS at 12-months was comparable in the nodal only and ITM only group (72.2% vs.70.1%, p=0.97) but lower in ITM and nodal disease patients (57.8%; p=0.01, p<0.01). Locoregional metastases occurred as first recurrence in 38.9% nodal disease only, 71.9% of ITM-only, and 44.0% of ITM and nodal disease patients. Distant recurrences occurred in 42.3%, 18.8%, and 36.0%, respectively (p=0.02). 12-months OS was not significantly different for nodal disease only patients compared to ITM-only (94.4% vs. 97.6%, p=0.06) but was significantly higher for ITM-only compared to ITM and nodal disease patients (97.6% vs. 91.0%, p<0.01) . In conclusion, we showed that in the adjuvant setting, RFS rates in ITM-only patients are similar to non-ITM, though better than in ITM and nodal disease patients. Adjuvant-treated ITM-only patients less often experience distant recurrences and have a superior OS compared to ITM and nodal disease patients. This article is protected by copyright. All rights reserved.