Regional differences in stage distribution and rates of treatment for adrenocortical carcinoma across United States SEER registries

BACKGROUND: We tested for regional differences across United States (US) in rates of adrenalectomy, systemic thera-py, and adrenalectomy and systemic therapy combination for adrenocortical carcinoma (ACC) patients. We hypothesized that no differences exist, especially after accounting for baseline patient and tumor characteristics.METHODS: Within Surveillance, Epidemiology, and End Results (SEER) database (2004-2018), 1275 ACC patients were identified. Distribution of patient age, tumor size, ENSAT (European Network for the Study of Adrenal Tumors) stages, and treatments were tabulated and graphically displayed, according to nine geographical registries, corresponding to the population of specific states, cities or macro areas of the US on which the data are based on. Multinomial models predicted treatment probability for each patient according to registries.RESULTS: Patients count according to registries ranged from 62 to 509. Differences across registries existed for age (range 54-59 years; P=0.4), tumor size (8.5-11.0 cm; P=0.2), ENSAT stage (1-11% vs. 17-35% vs. 18-32% vs. 24-44%, in respectively ENSAT stage I, II, III, and IV), and treatment distribution (35-53% vs. 5-21% vs. 23-42%, in respectively adrenalectomy, systemic therapy, and adrenalectomy and systemic therapy combination; P=0.039). After adjustment for age, stage and year of diagnosis, clinically meaningful residual differences across registries remained for adrenalectomy (33-54%), systemic therapy (4-19%), and adrenalectomy and systemic therapy combination (20-38%). However, most variability originated from registries with smallest sample sizes.CONCLUSIONS: We identified important variability in ACC treatment according to SEER geographical registries, even after considering baseline patient and tumor characteristics. These findings may be indicative of differences in quality of care or expertise in ACC management.