Population-Based Incidence of Conjunctival Melanoma in Various Races and Ethnic Groups and Comparison With Other Melanomas DAN-NING HU, GUOPEI YU, STEVEN A. MCCORMICK, AND PAUL T. FINGER ● PURPOSE: To investigate racial and ethnic differences in the incidence of conjunctival melanoma in a large population-based study. ● DESIGN: Observational cross-sectional study. ● METHODS: Using data from 1992 through 2003 pro- vided by the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program, we calculated age-adjusted incidence rates of conjunctival melanoma in various racial and ethnic groups (Black, American Indian, Asian and Pacific Islander, Hispanic, and non-Hispanic White). In addition, we calculated the standard incidence ratios (risk ratios) and 95% confi- dence intervals to describe the differences within these racial and ethnic groups. ● RESULTS: From 1992 through 2003, there were a total of 168 conjunctival melanomas diagnosed in 13 SEER registries with known racial and ethnic groups. The annual age-adjusted incidence rates (per million popula- tion) of conjunctival melanoma was 0.18 (Blacks), 0.17 (American Indians), 0.15 (Asians), 0.33 (Hispanics), and 0.49 (non-Hispanic Whites). The difference in the incidence of conjunctival melanoma between Whites and Blacks or Asians was statistically significant, but was not significant between Blacks and Asians. ● CONCLUSIONS: The overall White-to-Black incidence ratio in conjunctival melanoma was 2.6:1, which is much less than that of uveal melanoma (18:1) and cutaneous melanoma (13:1 to 26:1), but is similar to that of mucosal melanoma (2.2:1 to 2.3:1). The cause and significance of this difference of racial and ethnic inci- dence in various melanomas are discussed. (Am J Ophthalmol 2008;145:418 – 423. © 2008 by Elsevier Inc. All rights reserved.) T HE DIFFERENCE IN THE INCIDENCE OF UVEAL MELA- noma between various racial and ethnic groups has been well documented. 1–9 A recent study based on data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program revealed that there was significant difference in the incidence of uveal melanoma among different races and ethnicities. The population-based incidence of uveal melanoma was highest in non-Hispanic Whites, followed by Hispanics, Asians and Pacific Islanders, and Blacks, with a White-to- Black incidence ratio of uveal melanoma of 18:1. 1 The difference in the incidence of conjunctival mela- noma in various racial and ethnic groups has not been studied. Conjunctival melanoma mainly originates from the bulbar conjunctiva, limbus, and caruncle, which is exposed to solar radiation. 10 –14 Recently, epidemiologic and molecular biological studies suggested that conjuncti- val melanoma is similar to cutaneous melanoma in some aspects. Conjunctival melanoma is related to mutation of the BRAF gene and shows a trend in increasing incidence, whereas these are not found for uveal melanoma. 15–28 Cases of conjunctival melanoma in Blacks and Asians have been reported. 29–40 It is generally believed that conjunctival melanoma in Blacks is extremely rare, al- though it has been estimated that conjunctival melanoma may have a lower White-to-Black ratio as compared with uveal melanoma. 33,35,36,40 However, to our knowledge, there is no report on the incidence of conjunctival melanoma in various racial and ethnic groups in a popu- lation-based study. True estimates of the incidence of conjunctival mela- noma among various racial and ethnic groups must be performed using population-based data. The difficulty in constructing such an epidemiologic study is that it requires a minimum number of cases to provide meaningful results. The incidence of conjunctival melanoma is relatively low, and the incidence in several racial and ethnic groups is too low and the population studied too small to provide this information. Data from the National Cancer Institute’s SEER program is the most authoritative source for cancer epidemiologic characteristics and the best source of cancer incidence rates in the United States. The 13 population- based cancer registries included in the SEER program cover approximately 14% of the United States population and contain separate rates of various cancers for non- Hispanic Whites, Hispanics, Blacks, American Indians, and Asians since 1992. Herein, we analyze the incidence of conjunctival melanoma in various racial and ethnic groups based on data collected through the SEER program from Accepted for publication Oct 19, 2007. From the Departments of Pathology (D.-N.H., S.A.M.) and Ophthal- mology (D.-N.H., S.A.M., P.T.F.), and the Biostatics and Epidemiology Service (G.Y.), New York Eye and Ear Infirmary, New York, New York, and the Department of Ophthalmology, New York Medical College, Valhalla, New York (D.-N.H., S.A.M.). Inquiries to Dan-Ning Hu, Department of Pathology, The New York Eye and Ear Infirmary, 310 East 14th Street, New York, NY 10003; e-mail: dhu@nyee.edu © 2008 BY ELSEVIER INC.ALL RIGHTS RESERVED. 418 0002-9394/08/$34.00 doi:10.1016/j.ajo.2007.10.022