Treatment of High Risk Resected Melanoma in Australia: Current Landscape and Practises

Abstract

Stage III melanoma involves regional lymph nodes and/or in-transit or satellite disease, without spread to distant metastatic sites. Stage IIIA melanoma includes a T1a-T2a primary lesion with N1a or N2a nodal involvement, whilst stage IIID melanoma includes a T4b primary lesion with N3a-N3c nodal involvement. With surgery alone, patients with stage IIIA melanoma have 10-year survival rates of ~88%; however, patients with stage IIID melanoma have 10-year survival rates of only ~24%. Targeted therapy and immunotherapy are being explored in stage III disease as adjuvant therapy after surgical resection, to eliminate micro-metastatic disease and thereby prevent relapse of melanoma and increase patient survival. A number of pivotal trials published in the last two years have shown improved relapse-free survival (RFS) and overall survival in patients with stage III melanoma treated with adjuvant therapy. COMBI-AD showed adjuvant dabrafenib and trametinib improving RFS compared with placebo (HR 0.49; 95% CI 0.40-0.59). Checkmate-238 demonstrated an improvement in RFS of adjuvant nivolumab over ipilimumab (HR 0.68, P < 0.001) whilst Keynote-054 demonstrated an improvement in RFS with adjuvant pembrolizumab over placebo (HR 0.57, P < 0.001). Many nuances need to be considered when interpreting this data, including implications of an updated staging system, which patients are suitable for adjuvant therapy and the choice between adjuvant targeted therapy and immunotherapy in BRAF mutant patients. This review article summaries the currently available literature on adjuvant targeted therapy and provides a guide on applying this data in everyday practise.

Keywords: adjuvant therapy; immunotherapy; melanoma; melanoma recurrence; targeted therapy.