Impact of staging on survival outcomes: a nationwide real-world cohort study of metastatic uveal melanoma.

No data exist regarding whether any first-line treatment for metastatic uveal melanoma provides overall survival (OS) benefit, if staged and compared to best supportive care (BSC). We analyzed OS in a nationwide, consecutive cohort diagnosed with metastatic uveal melanoma between January 1999 and December 2016. The Helsinki University Hospital Working Formulation was used to assign patients to stage IVa, IVb and IVc, corresponding to predicted median OS ≥12, <12-6 and <6 months, respectively. OS of 216 actively treated patients was compared by treatment and working formulation stage against 108 similarly staged, concurrent patients managed with BSC using Kaplan-Meier analysis and Cox regression. The median OS with active treatment was 18 (range, 0.7-162), 6.9 (range, 1.3-30) and 1.9 (range, 0.2-18) months in working formulation stage IVa, IVb and IVc, respectively. Patients who received chemoimmunotherapy, selective internal radiation therapy, or underwent surgical resection survived longer - median OS 13, 16 and 24 months, respectively - than those receiving conventional chemotherapy - median OS 5.1 months - but only with surgical resection their OS exceeded that with BSC, both overall and in stage IVa (P < 0.001, P = 0.010). In stage IVb and IVc, no difference in OS was observed in any comparison. Staging of patients is crucial when comparing survival after metastatic uveal melanoma. Only surgical resection for stage IVa disease provided longer OS in our national cohort. We additionally recommend stage-specific comparison of novel treatments against available BSC data.