OBJECTIVES: Late regional complications in prostate cancer can impact quality of life and require numerous medical interventions.  The objective was to evaluate late regional complications in castration-resistant prostate cancer (CRPC) by type of initial local primary treatment (external-beam radiotherapy (EBRT) or radical prostatectomy (RP)) previously received. METHODS: The cohort consists of CRPC patients that died between 2001 and 2013 in Quebec, and who underwent previous initial local primary therapy. Medical procedures due to regional complications of disease were identified from the administrative RAMQ databases.  Late regional complications were defined as urological procedures, rectal procedures and major surgical procedures received in the last two years of life.  Kaplan-Meier analysis and Cox regression were used to evaluate overall survival by initial treatment.  Logistic regression was used to measure the association between initial local primary treatment and risk of regional complications in the last 2 years of life. RESULTS: The cohort is comprised of 1189 patients; 535 (45%) and 654 (55%) patients had received EBRT and RP, respectively. Median survival was 7.1 years in the EBRT group and 7.2 years in the RP group.  The type of initial local treatment was not associated with survival (HR, 1.01; 95% CI, 0.90 to 1.14), however age (HR, 1.29; 95%CI, 1.15 to 1.45) and late regional complications (HR, 1.13; 95%CI, 1.01 to 1.27) were.  Overall 47.3% of patients experienced at least one late regional complication in the last 2 years of life; with urological procedures (EBRT: 32%, RP: 34%) being the most common type.  When adjusted for several covariables, RP was not associated with a reduced risk of late regional complications compared to EBRT (OR, 1.01; 95%CI: 0.79 to 1.27). CONCLUSIONS: Using a retrospective population-based approach, the risk of late regional complications in CRPC wasn’t associated with the type of initial local primary treatment (RP or EBRT) in this cohort.