Sex disparity in survival of patients with uveal melanoma: Better survival rates in women than in men in South Korea

Purpose: The purpose of this study was to determine the survival rate of patients with uveal melanoma and sex disparity in this rate in South Korea. Methods: We extracted incident uveal melanoma patients using the Korea Central Cancer Registry (KCCR) database, which covered the entire population from 1999 to 2012 in South Korea. We estimated all-cause survival probabilities and cancer-specific survival probabilities of patients with uveal melanoma and compared these probabilities between subgroups (sex, tumor site, age at diagnosis, etc.) using Kaplan-Meier methods and log-rank tests. We fitted the Cox-proportional hazards models for all-cause death and cancer death to determine sex disparities in survival. Results: A total of 344 uveal melanoma patients (175 women, 51%) were ascertained. They comprised 283 patients with choroidal melanoma (82%) and 61 patients with ciliary body/iris melanoma (18%). The observed 5-year survival probability from all-cause death was 75% (95% confidence interval [CI]: 69%-79%); women with uveal melanoma showed higher survival probability (83% [95% CI: 76%-89%]) compared with men (66% [95% CI: 58%-73%], P < 0.01). After adjusting for age, year of diagnosis, tumor sites, and diagnostic verification method, the hazards for all-cause death and cancer death in women with uveal melanoma were lower than those in men (hazards ratio for cancer death = 0.50 [95% CI: 0.30-0.81]; hazards ratio for all-cause death = 0.39 [95% CI: 0.25-0.61]). Conclusions: Women with uveal melanoma have better survival probabilities relative to men with uveal melanoma. Our findings show a comprehensive picture of survival probability in uveal melanoma cancer patients in Korea, which requires further investigation of mechanism of the sex disparity in uveal melanoma.