TY - JOUR AU - Martin, Lisa J. AU - Alibhai, Shabbir M.H. AU - Komisarenko, Maria AU - Timilshina, Narhari AU - Finelli, Antonio PY - 2018/11/05 Y2 - 2024/03/28 TI - Identification of subgroups of metastatic castrate-resistant prostate cancer (mCRPC) patients treated with abiraterone plus prednisone at low- vs. high-risk of radiographic progression: An analysis of COU-AA-302 JF - Canadian Urological Association Journal JA - CUAJ VL - 13 IS - 6 SE - Original Research DO - 10.5489/cuaj.5586 UR - https://cuaj.ca/index.php/journal/article/view/5586 SP - AB - <p><strong>Introduction:</strong> Radiographic imaging is used to monitor disease progression for men with metastatic castrate-resistant prostate cancer (mCRPC). The optimal frequency of imaging, a costly and limited resource, is not known. Our objective was to identify predictors of radiographic progression to inform the frequency of imaging for men with mCRPC.</p><p><strong>Methods:</strong> We accessed data for men with chemotherapy-naive mCRPC in the abiraterone acetate plus prednisone (AA-P) group of a randomized trial (COU-AA-302) (n=546). We used Cox proportional hazards modelling to identify predictors of time to progression. We divided patients into groups based on the most important predictors and estimated the probability of radiographic progression-free survival (RPFS) at six and 12 months.</p><p><strong>Results:</strong> Baseline disease and change in prostate-specific antigen (PSA) at eight weeks were the strongest determinants of RPFS. The probability of RPFS for men with bone-only disease and a ≥50% fall in PSA was 93% (95% confidence interval [CI] 87–96) at six months and 80% (95% CI 72–86) at 12 months. In contrast, the probability of RPFS for men with bone and soft tissue metastasis and &lt;50% fall in PSA was 55% (95% CI 41–67) at six months and 34% (95% CI 22–47) at 12 months. These findings should be externally validated.</p><p><strong>Conclusions:</strong> Patients with chemotherapy-naive mCRPC treated with first-line AA-P can be divided into groups with significantly different risks of radiographic progression based on a few clinically available variables, suggesting that imaging schedules could be individualized.</p> ER -