International validation of a staging system for ciliary body and choroidal melanomas using estimated tumour volume.

In competing risk regression, it produced a higher Wald statistic (761 vs 628) and a subdistribution hazard ratio of 1.42 versus 1.22.

Cox regression for melanoma-related mortality demonstrated higher hazard ratios, peaking at 24 for the new model compared with 13 for the AJCC classification.

Cumulative incidence analyses revealed 15-year metastatic death rates ranging from 7% to 76% with the new system versus 11% to 69% with AJCC, widening the absolute range by 11 percentage points.