PURPOSE: To evaluate the prognostic value of estimated tumour volume as a continuous biomarker in uveal melanoma and to compare its discriminative performance with the American Joint Committee on Cancer (AJCC) staging and multiplex ligation-dependent probe amplification (MLPA)-based genetic risk classification. METHODS: This retrospective cohort study included consecutive patients with choroidal or ciliary body melanoma treated between 2016 and 2024 at a tertiary ocular oncology centre. Tumour volume (mm³) was calculated from baseline ultrasonography using an ellipsoidal (oval-base) approximation. The primary endpoint was metastasis-free survival (MFS). Survival was analysed using Kaplan-Meier methods and Cox regression. In the genetic subset, Firth-penalised Cox regression was applied. Prognostic discrimination was assessed using Harrell's concordance index (C-index) for AJCC stage, tumour volume, MLPA profile and combined models. RESULTS: A total of 237 patients were included (mean age 65.5±13.8 years; 54.0% female). Median follow-up was 61.0 months, and 64 patients developed metastasis during follow-up. Higher tumour volume was significantly associated with worse MFS, corresponding to an approximately 10% increase in hazard per 100 mm³ (HR 1.10; 95% CI 1.05 to 1.13; p<0.001). Continuous tumour volume showed higher discrimination than AJCC staging alone (C-index 0.73 vs 0.66). The highest discrimination was observed in models combining tumour volume and MLPA profile, with limited additional gain after including AJCC stage (C-index 0.79 in the MLPA subset). CONCLUSIONS: Continuous tumour volume provides more refined prognostic stratification in uveal melanoma and complements AJCC staging. Integrating volumetric, anatomic and molecular biomarkers improves risk assessment and may support individualised surveillance strategies.
Gutiérrez-Cuesta et al. (Mon,) studied this question.