Prevalence of nonmetastatic (M0) prostate cancer (PC) patients on continuous androgen deprivation therapy (ADT) in the United States.

4659 Background: ADT is the cornerstone treatment of metastatic PC, but the nature and extent of its use in the M0 setting is less well-described. We sought to estimate the current prevalence of M0 PC patients actively receiving continuous ADT (≥6 months) in the US. Methods: Two point-prevalent cohorts on 12/31/2008 with continuous insurance coverage in 2008 were assembled: men aged 45-64 years (yrs) enrolled in commercial health plans (MarketScan) and men aged ≥67 yrs enrolled in fee-for-service (FFS) Medicare (Medicare 5% sample). Among those with evidence of PC and no evidence of metastases, we selected men who had continuous exposure to gonadotropin-releasing hormone agonists during at least the last 6 months of 2008 or received bilateral orchiectomy prior to 7/1/2008. The number of prevalent ADT users was extrapolated to the entire national commercially insured population aged 45-64 yrs and to the entire Medicare FFS population aged ≥65 yrs using person-level weights. Applying age-specific prevalence...