Adjuvant treatment of in‐transit melanoma: Narrowing the knowledge gap left by clinical trials

• Published in: International journal of cancer Vol. 153; no. 2; pp. 389 - 398
• Main Authors: Meza, Melissa M., Blokx, Willeke A. M., Bonenkamp, Han J., Blank, Cristian U., Aarts, Maureen J. B., Berkmortel, Franchette W. P. J., Boers‐Sonderen, Marye J., Groot, Jan Willem B., Haanen, John B., Hospers, Geke A. P., Kapiteijn, Ellen W., Not, Olivier J., Piersma, Djura, Rijn, Rozemarijn S., Stevense‐Den Boer, Marion A., Veldt, Astrid A. M., Vreugdenhil, Gerard, Eertwegh, Alfons J. M., Suijkerbuijk, Karijn P. M., Wouters, Michel W. J. M.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 15.07.2023; Wiley Subscription Services, Inc
• Subjects: Adjuvant therapy; adjuvant treatment; Cancer; checkpoint inhibition therapy; Clinical outcomes; Clinical trials; Combined Modality Therapy; Humans; immunotherapy; Inhibitor drugs; in‐transit melanoma; Medical research; Melanoma; Melanoma - pathology; Melanoma, Cutaneous Malignant; Metastases; Population studies; Skin Neoplasms - pathology; Survival; melanoma; adjuvant treatment; in-transit melanoma; checkpoint inhibition therapy; immunotherapy
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.34485

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 and December 2020. 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 analyzed. 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% vs70.1%, P = .97) but lower in ITM and nodal disease patients (57.8%; P = .01, P < .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 = .02). 12‐months OS was not significantly different for nodal disease only patients compared with ITM‐only (94.4% vs 97.6%, P = .06) but was significantly higher for ITM‐only compared with ITM and nodal disease patients (97.6% vs 91.0%, P < .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 with ITM and nodal disease patients. What's new? In some melanoma cases, metastases arise between the primary tumor site and the first draining regional lymph node, called in‐transit melanoma (ITM). Here, the authors investigated the efficacy of adjuvant treatment for ITM. In patients with stage III, adjuvant‐treated melanoma, recurrence‐free survival after 12 months was comparable between patients with nodal disease only and those with ITM only, but shorter in patients with both. This is the first large cohort study on adjuvant‐treated ITM, and the results suggest that nodal status could indicate different treatment strategies for ITM patients.