Estimating the risk of malignant transformation of a choroidal nevus

Abstract

Purpose: To estimate the risk of malignant transformation of a choroidal nevus in the white population.

Design: Systematic literature review.

Methods: A literature review was performed to obtain data on the prevalence of choroidal nevi in the white population. Data from studies that used indirect ophthalmoscopy or otherwise corrected data to include the entire fundus were selected. Only studies reporting on the United States population were included. The number of affected individuals was estimated using 2000 U.S. census data. The estimate of annual incident choroidal melanoma cases in the corresponding age- and race-matched population was calculated using the Surveillance, Epidemiology, and End Result database (1973-2000). Average annual age-specific incidence rates for 1973 to 2000 for each of the 5-year age groups (adjusted for the U.S. 2000 population) were calculated and applied to the corresponding census data. The ratio of numbers of affected individuals with choroidal melanoma and choroidal nevi gave the annual rate of malignant transformation of a choroidal nevus.

Main outcome measures: Annual rate of malignant transformation of a choroidal nevus in the white population of the U.S.

Results: The prevalence of choroidal nevus in the white U.S. population ranged from 4.6% to 7.9%. It was estimated that, on average, 8864625 individuals in the U.S. had a choroidal nevus. The number of individuals with choroidal melanoma in the corresponding age- and race-matched population ranged from 989 to 1008 (mean, 1002). The annual rate of malignant transformation of a choroidal nevus was estimated to be 1 in 8845.

Conclusions: If it is assumed that all choroidal melanomas arise from preexisting nevi, then the published data suggest a low rate (1/8845) of malignant transformation of a choroidal nevus in the U.S. white population.