Non-Conditional and Conditional Metastasis of Uveal Melanoma Per Millimeter-By-Millimeter in Thickness in 8034 Patients

Purpose: To determine the impact of uveal melanoma thickness on patient survival from the date of presentation and at specific time intervals following metastasis-free survival. Methods: In this retrospective cohort study, we evaluated data from 8034 consecutive uveal melanoma patients diagnosed at a tertiary care ocular oncology center between May 1972 and August 2007. The patients were categorized on the basis of tumor thickness (per each 1-mm increment) and evaluated for non-conditional survival (from date of presentation) and conditional survival (with 3-years, 5-years, and 10-years of metastasis-free survival) on the cumulative incidence of melanoma-related metastasis at 5-, 10-, 15-, 20-, 25- and 30-years. Results: For the entire cohort, Non-conditional incidence of metastasis at 5-, 10-, 15-, and 30-years was 8%, 11%, 12%, and 12%. Conditional cumulative incidence of metastasis with 5-year and 10-year metastasis-free survival revealed 30-year incidence of metastasis at 10% and 8%, respectively. The multivariate Cox regression analysis showed that each 1-mm increase in tumor thickness was associated with a significant (p < .05) increase in the risk of metastasis [HR: 1.08 (95% CI: 1.05-1.11) for non-conditional survival, HR: 1.07 (95% CI: 1.03-1.11) for 3-year metastasis-free survival, HR: 1.09 (95% CI: 1.03-1.15) for 5-year metastasis-free survival, and HR: 1.17 (95% CI: 1.05-1.30) for 10-year metastasis-free survival]. Conclusion: In this study, we emphasize that increasing the thickness of uveal melanoma at presentation demonstrates a poorer ultimate prognosis. However, those with longer metastasis-free intervals were found to have a lower risk of ultimate metastatic disease, highlighting the importance of conditional and non-conditional survival.