Long‐Term Local Control and Mortality After Transpupillary Thermotherapy of Small Uveal Melanomas

BACKGROUND: Transpupillary thermotherapy (TTT) is used for selected small choroidal melanocytic tumours, either as primary treatment or as an adjunct to plaque brachytherapy. We compared long-term local recurrence and mortality outcomes after primary TTT alone, plaque brachytherapy combined with TTT (brachy+TTT), and plaque brachytherapy alone (brachy alone). METHODS: This retrospective cohort study included 850 patients with choroidal melanocytic tumours treated with eye-preserving modalities at St. Erik Eye Hospital, Stockholm, Sweden, 2008-2020. Primary treatment was TTT alone (n = 48), brachy+TTT (n = 105), or brachy alone (n = 697). Outcomes included local recurrence, local recurrence with extraocular extension (EXE), and mortality. RESULTS: At 15 years, Kaplan-Meier local recurrence-free survival was 8% after TTT alone, 34% after brachy+TTT, and 86% after brachy alone (log-rank test for trend, p < 0.001). Disease-specific survival at 15 years was 46%, 85%, and 90%, respectively (p = 0.03). In multivariable Fine-Gray regression adjusting for American Joint Committee on Cancer stage, TTT alone was associated with a higher subdistribution hazard of local recurrence (sHR, 6.7; p < 0.001) and melanoma-related death (sHR, 3.9; p < 0.001). Among patients treated for local recurrence, subsequent recurrences occurred more frequently after TTT than after treatments involving brachytherapy. The risk of EXE increased with the number of TTT sessions. CONCLUSIONS: In this single-centre retrospective cohort, TTT was associated with higher rates of local recurrence and melanoma-related mortality compared with plaque brachytherapy. Future studies should assess whether similar results are observed in external long-term cohorts; such findings would inform whether the role of TTT in the management of choroidal melanocytic tumours warrants reconsideration.