7450 Geographic Hotspots Of Adrenocortical Carcinoma (ACC) In Colorado

Abstract Disclosure: T.B. Holmstoen: None. L.K. Volino: None. T. Banerjee: None. L. Fishbein: None. K. Kiseljak-Vassiliades: None. M.E. Wierman: None. Background: Adrenocortical carcinoma (ACC) is an under-investigated endocrine malignancy, with a reported annual incidence in the United States of 0.5-2 cases per million. The genetic profiles of ACC patients exhibit great heterogeneity, and 40% of cases have an unknown driver. We have observed an increase of ACC cases originating from western Colorado – a place of lower population, greater elevation, and focus on farming as well as oil and mining-related activities. Given this observation, we hypothesized there may be environmental factors associated with higher ACC incidence in western CO. Methods: We employed a population-based retrospective cohort study to analyze the characteristics of consecutive patients with ACC from Colorado who were seen in our multidisciplinary Adrenal Tumor Program between 2012 and 2023. Data collection included patient’s sex, age, date of diagnosis, and ZIP code of residence. Colorado population data were collected from the 2020 CO Census records. To classify location as western or eastern CO, patient ZIP codes were grouped into their appropriate counties, 21 of which are defined as western CO by the state demography office. The remaining 43 counties were considered to be eastern CO. ZIP code data were also collected from consecutive patients with pheochromocytoma or paraganglioma (PPGL) from Colorado, and these cases were classified as western or eastern CO using the same methods as described above. Chi-square tests were performed for the statistical comparison of population proportions. Results: Between 2012 and 2023, there were 62 incident cases of ACC in the state of Colorado. Given that the state population is 5.7 million, this equates to an average annual incidence of about 0.81 cases per million. Out of the 62 Colorado cases, 38 (61.2%) were female and 24 (38.7%) were male. The average age of diagnosis was 48.9 years. Of interest, the average annual incidence of ACC was increased at 1.44 per million in western CO and only 0.76 per million in eastern CO (p=0.024). The same analysis for 163 PPGL cases yielded no such difference, with an annual incidence of 3.2 cases per million in western CO, and 3.57 cases per million in eastern CO (p=0.7884). Conclusion: The overall clinical demographics and annual incidence of ACC in our Colorado cohort are similar to reported literature. However, the incidence of ACC in western CO is about twice as high as in eastern CO. Since this geographic dichotomy is not also observed in PPGL cases, these data suggest that environmental or other factors may play a role in ACC development. These data warrant further investigation of risk factors that predispose to ACC. Presentation: 6/3/2024