INTRODUCTION: Uveal melanoma (UM) is the most common intraocular malignancy in adults. Despite successful local treatments, long-term survival is still a challenge, making early diagnosis of paramount importance. Comprehension of geographical disparities can influence disease surveillance and prognostic counseling. This study aimed to report UM incidence trends and to analyze their geographical variation in Portugal. METHODS: A prospective, observational study was conducted at the Portuguese UM referral center between July 2013 and December 2022. Crude incidence rates and age-standardized incidence rates (ASIR) were calculated. Overall survival (OS) and disease-specific survival (DSS) were estimated and a multivariate Cox analysis was performed to evaluate the effect of tumor characteristics and patient demographics on survival. RESULTS: A total of 316 patients were included. The mean age at diagnosis was 61.8±14.2 years. The Health Region (HR) of Lisbon and the Tejo River was responsible for most referrals to our center (n=119, 37.7%). Overall ASIR in Portugal was 2.4 cases per million people (95% CI: 2.1-2.8). Higher crude incidence rates were noted in the central coastal districts (5.4 per million people in Aveiro (95% CI: 3.3-7.5) compared with the southern districts (1.0 per million in Faro (95% CI: 0.2-1.7). Geographical analysis showed incidence variation across HR, with the Centro region presenting a higher incidence crude rate (4.0 per million). The 5-year OS rate was 84.6% (95% CI: 78.7-91.1). No significant differences were found in OS (p=0.74) or DSS (p=0.83) when the data was stratified by HR. Cox regression analysis revealed that only basal tumor dimension was significantly associated with lower OS and DSS (HR= 1.33, p<0.001). CONCLUSION: This is the first study to report the incidence of UM and to analyze regional incidence rates in Portugal. Overall ASIR of UM indicates no sex predilection and lower incidence rates compared to the ones reported in Northern European countries. Geographical variation of crude incidence rates revealed the highest in central coastal districts of Portugal, but no significant differences were found in OS or DSS by Health region or district. Basal tumor diameter was the only predictor of DSS in UM for the Portuguese population in this analysis.
Machado et al. (Mon,) studied this question.