Incidence and Survival of Patients With Conjunctival Melanoma in Europe.

Importance: Conjunctival melanoma (CM) is a rare ocular tumor. Estimates of incidence and survival of patients with CM are important to researchers and policy makers. Objective: To estimate incidence and survival of patients with CM in Europe. Design, Setting, and Participants: This population-based cohort study used data from 41 European cancer registries adhering to the RARECAREnet project. All individuals diagnosed as having malignant CM from January 1995 to December 2007 coded according to the International Classification of Diseases for Oncology, Third Edition codes C69.0 (conjunctiva) and 8720-8780 (melanoma) were included. Analysis began March 2019. Main Outcomes and Measures: Trend estimates for incidence and for 5-year relative survival (the ratio of the measured survival of patients to the expected survival in the general population for the same country, age, sex, and calendar year). Crude, age-standardized, and bayesian incidence rates were calculated. Five-year relative survival was calculated by the Ederer II method with the cohort and period approach. Results: A total of 724 patients 15 years or older (512 [70.7%] were 55 years or older; 366 [50.6%] were female) were analyzed with an overall crude incidence of CM (per 1 000 000 person/y) of 0.46 (95% CI, 0.42-0.49). Crude incidence was similar in men and women (0.48; 95% CI, 0.44-0.54 and 0.46; 95% CI, 0.41-0.51, respectively) and increased with age. Age-standardized incidence increased over time only in men and was the highest in Norway and the Netherlands (more than 0.70). Only 1 case in 14 years was estimated to occur in Iceland vs about 20 cases per year in large countries such as France and Germany. Percentage of 5-year survival (83.5 overall; 95% CI, 78.6-87.3) was not different between adult and elderly patients but showed large geographical disparities across European regions (range, 66-89) and improved markedly in male patients (from 76 in 1995-1998 to 86 in 2003-2007, with a difference of 10.2 [95% CI, 1.3-19.2]; P < .05) becoming similar to that of women in the last period. Conclusions and Relevance: Although these data are only available through 2007 and based on registries not uniformly covering the European population, the study provides the first Europe-wide estimates of the incidence and relative survival of patients with CM using population-based data. Geographical differences in survival indicate room for outcome improvement in Southern, Northern, and Eastern European countries.