Abstract 5212: A comparative descriptive study of cutaneous malignant melanoma

Objectives: Incidence of cutaneous malignant melanoma has increased worldwide in the past several decades, particularly in developed countries. Melanoma is believed to be a multifactorial condition, with exposure to ultraviolet radiation (UVR) as a major environmental risk factor. We matched five provinces in Iran with five states in the United States (US) based on measurements of solar UVB exposure and conducted a comparison of population-based incidence rates of melanoma in each province and state. Methods: Solar UVB exposure was measured using data from NASA9s Total Ozone Mapping Spectrometer (TOMS) for the period between January 1, 1997 and December 31, 2000 at a geographic resolution of one degree. UV exposures (in mW/m2) for each state and province were calculated by averaging the values of the grid points within each state and province. Population-based incidence data for five Iranian provinces (Ardabil, Golestan, Mazandaran, Gilan and Kerman) were obtained from their respective cancer registries. Incidence rates among white non-Hispanic individuals in the five US states (Kentucky, Utah, Texas, Oklahoma, and Hawaii) with matching average UVB exposure to the Iranian provinces were obtained from the North American Association of Central Cancer Registries. Furthermore, population-based incidence rates of melanoma for the overall U.S. population were obtained from the Surveillance, Epidemiology, and End Results (SEER) program for the 13 SEER areas (1996-2000). All incidence rates were calculated per 100,000 person-years and were age-adjusted using the 2000 standard populations. Results: Annual UVB exposure from 1996-2000 ranged from an average of 138.52 in Ardabil to 227.44 in Kerman. The exposures of the corresponding US states ranged from 124.95 in Kentucky to 246.34 in Hawaii during the same period. The overall male and female rates of melanoma were 0.59 and 0.46, respectively, for Iran and 14.9 (95%CI: 14.7-15.2) and 10.5 (95%CI: 10.4-10.7), respectively, for the US. Age-standardized rates (ASR) of melanoma among males for the five Iranian provinces in comparison to their UVR-matched US states were as follows: 0.30 (22.6) for Ardabil (Kentucky), 1.20 (26.6) for Golestan (Utah), 0.73 (18.1) for Mazandaran (Texas), 0.17 (15.8) for Gilan (Oklahoma), and 0.90 (75.3) for Kerman (Hawaii). ASR of melanoma among females were as follows: 0.20 (16.0) for Ardabil (Kentucky), 0.60 (17.5) for Golestan (Utah), 0.47 (10.6) for Mazandaran (Texas), 0.17 (8.9) for Gilan (Oklahoma), and 0.90 (36.5) for Kerman (Hawaii). Conclusion: The markedly higher incidence rates of melanoma in selected US states compared to Iranian provinces with similar UVR exposure patterns may be due to differences in lifestyle, pigmentation, or genetic profiles, as well as under-reporting in Iran compared to the US. Our findings underscore the need for additional studies to decipher the multitude of extrinsic and intrinsic factors involved in the etiology of this multifactorial condition. Citation Format: Roxana Moslehi, Francis B. Boscoe, Nur Zeinomar. A comparative descriptive study of cutaneous malignant melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5212.