Purpose: While the incidence of cutaneous melanoma has been found to have increased over time, the evidence for conjunctival melanoma is not as clear. We applied a large cancer registry database to determine whether any changes had occurred in the incidence of conjunctival melanoma.
Design: Descriptive epidemiologic analysis.
Method: Using population-based registry data from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute (NCI), we identified 206 newly diagnosed patients with conjunctival melanoma from 1973 to 1999. For analysis purposes, we calculated age-adjusted incidence rates and described temporal changes, using joinpoint regression model.
Results: Overall estimated biannual percent change (EBAPC) was 5.5 (95% confidence interval [CI] = 2.3, 8.8; P <.001). The significant elevated trend was observed for white men (EBAPC = 11.2; 95% CI = 6.3, 16.3; P <.001) but not for white women (EBAPC = 0.3; 95% CI = -4.1, 4.9; P >.05). In white men, the incidence rate increased 295% within the 27 years. Our analysis also showed a significant upward trend in the age group aged 60 years or more (EBAPC = 7.6; 95% CI = 3.9, 11.3; P <.001). Incidence tended to rise in the group aged 40 to 59 years, but it was not statistically significant (EBAPC = 4.4; 95% CI = -2.3, 11.6; P =.1536).
Conclusions: Substantial temporal changes in the incidence of conjunctival melanoma have occurred in the United States in recent years. The changing incidence patterns coincide with those seen in cutaneous melanoma, suggesting a possible link to a sunlight-related etiology.