561 Metastasectomy for Stage IV Melanoma in the Effective Systemic Treatment Era

Abstract

Abstract Aim Historically, a diagnosis of Stage IV melanoma was a dire one, with low survival rates and ineffective treatment. The only beneficial treatment option was metastasectomy in very selected cases. The recent introduction of the effective systemic therapy agents (EST) (immunotherapy and BRAF inhibitors) dramatically changed this. This research’s aim is to determine if EST + Metastectomy significantly improves OS. And if so, should be considered as the main therapeutic approach to stage IV melanoma patients. Method Single-centre retrospective cohort study from the Melanoma Unit at Calvary Mater Hospital in Australia was conducted, approved by the ethics committee. Inclusion criteria was Stage IV Melanoma patients who received EST from 2009-2019. OS of those who received EST alone are compared to EST + Metastasectomy. The 2 groups were compared retrospectively based on their disease characteristics, using probability score weighting analysis and survival curve. Results This is a preliminary analysis for the first 200 patients, data collection is ongoing. Mean OS is 2 years. Several combinations of immunotherapy treatments were identified. Of the 200 patients, 35% underwent metastasectomy. Mean survival for those who had surgery is 3 years, as oppose to 2 years for those who had EST alone. OS in the Metastasectomy group was higher than those who had EST alone, of 47.1% and 42.3% respectively. The Kaplan Meier curve also shows increase survival in the metastasectomy group, up to year 6 post diagnosis. Conclusions Metastasectomy for stage iv melanoma in the EST era appears to offer a survival benefit in selected patients