A retrospective observational study assessing bone metastases (mets) detection and management of patients (pts) with castration-resistant prostate cancer (CRPC) in Canada

161 Background: Canadian Urological Association guidelines outline the scheduling of imaging modalities based on prostate-specific antigen doubling time (PSADT) to screen for mets in pts with nonmetastatic (M0) CRPC and to manage pts with metastatic (M1) CRPC. Data describing guideline adoption and real-world timing of bone scans and treatment patterns in Canadian CRPC pts are limited. Methods: A retrospective chart review conducted at 13 Canadian urology practices included pts with CRPC (PSA ≥2 ng/mL despite androgen deprivation therapy) sequentially identified in reverse chronological order starting July 30, 2015. Pts had no mets at CRPC diagnosis (index date). Data were abstracted from the index date to the chart review date. Coprimary objectives were to describe CRPC management in terms of timing of the 1st and repeat bone scans in M0 and treatment patterns when pts became metastatic. Secondary objectives described nonbone imaging. Results: 232 pts enrolled. Over the observation period 109 remained nonmetastatic (M0 cohort); 123 developed mets (M1 cohort). Median index PSADT was ~1.5x greater for the M0 cohort than the M1 cohort. 68 pts (71.6%) in M0 and 117 pts (95.1%) in M1 had ≥1 bone scan. Median (95% CI) months from CRPC diagnosis to 1st bone scan was 7.5 (5.6–9.6) for pts in M1 and 15.7 (10.0–23.0) for pts in M0. Median (95% CI) months from identification of mets to start of treatment for the M1 cohort was 3.2 (2.3–5.7). The most common therapies were abiraterone (55%) and enzalutamide (42%), with respective median (95% CI) durations of 12.7 (8.7–23.3) and 15.7 months (10.4–NE). 25% of pts received a bone-targeted agent. Conclusions: In CRPC, time to first bone scan was shorter for pts who subsequently developed mets or had rapid PSADT. Abiraterone and enzalutamide were the most common therapies in pts with mets. [Table: see text]