e22126 Background: AIs and ADT are used to prevent recurrence of breast and prostate cancers but have been shown to accelerate bone loss. We estimated the prevalence of early-stage ER+ breast and prostate cancer patients on hormone therapy in the U.S., as this is not well-described in the literature. Methods: Data from the Surveillance, Epidemiology, and End Results (SEER) Program, published literature, clinical practice, and a large claims database were used. We began with the American Cancer Society's estimated number of new breast and prostate cancer cases for the year 2008. We then assessed the number of patients with localized/regional disease and ER+ tumors and those receiving primary ADT (both chemical and surgical) or AI therapy by applying proportions from SEER, published literature, clinical practice, and the claims database. Using these incident case counts, we calculated the 5-year prevalence using appropriate cohort-specific survival rates to sum the number of new and surviving cases over a 5-year period. Results: The estimated 5-year prevalence of early-stage ER+ breast cancer for women aged ≥50 years in the U.S. was 607,411, of which 293,904 (48.4%) were on AI therapy based on the claims database. However, because this data source was limited to women aged <65 years, we also used estimates from clinical practice to capture AI use for women of all ages. Based on clinical practice, 402,637 (66.3%) to 460,156 (75.8%) of early-stage ER+ breast cancer patients were on AI therapy. For early-stage prostate cancer, the estimated 5-year prevalence for all ages was 1,024,238, of which 141,451 (13.8%) were on primary ADT. However, these figures may underestimate current usage of hormone therapies, as our data and the literature show increasing trends in ADT and AI use for early-stage disease. Conclusions: Based on a combination of population-based data and the published literature, approximately half of all early-stage ER+ breast cancer patients and a modest proportion of early-stage prostate cancer patients are on hormone therapy in the U.S. [Table: see text]
Information needs of early-stage prostate cancer patients: within- and between-group agreement of patients and health professionals