Cut-points for PSA doubling time in men with non-metastatic castration-resistant prostate cancer.

To examine whether PSADT correlates with metastases, all-cause mortality (ACM), and prostate cancer-specific mortality (PCSM) and identify PSADT cut-points that can be used clinically for risk stratification in men with M0 CRPC.

We collected data on 441 men with M0 CRPC in 2000-2015 at five Veterans Affairs hospitals. Cox models were used to test the association between log-transformed PSADT and development of metastasis, ACM, and PCSM. To identify cut-points, we categorized PSADT into groups of every 3 months and then combined groups with similar hazard ratios.

Median follow-up was 28.3 months (IQR: 14.7-49.1). As a continuous variable, PSADT was associated with metastases, ACM, and PCSM (HR 1.40-1.68, all p<0.001). We identified the PSADT cut-points <3, 3-8.9, 9-14.9, ≥15 months. As a categorical variable, PSADT was associated with metastases, ACM, and PCSM (all p<0.001). Specifically, PSADT <3 months was associated with about 9 times increased risk of metastases (HR 8.63, 95%CI 5.07-14.7) and PCSM (HR 9.29, 95%CI 5.38-16.0), and 4.7 times increased risk ACM (HR 4.71, 95%CI 2.98-7.43) on multivariable analysis compared to PSADT ≥15 months. Median times to metastasis for patients with PSADT <3, 3-8.9, 9-14.9, and ≥15 months were 9, 19, 40, and 50 months, respectively.

PSADT was a strong predictor of metastases, ACM, and PCSM in patients with M0 CRPC. As with patients at earlier disease stages, <3, 3-8.9, 9-14.9, and ≥15 are reasonable PSADT cut-points for risk stratification in men with M0 CRPC. These cut-points can be used for selecting high-risk men for clinical trials. This article is protected by copyright. All rights reserved.

BJU international. 2017 Mar 28 [Epub ahead of print]

Lauren E Howard, Daniel Moreira, Amanda De Hoedt, William J Aronson, Christopher J Kane, Christopher L Amling, Matthew R Cooperberg, Martha K Terris, Stephen J Freedland

Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC., Department of Urology, University of Illinois at Chicago, Rochester, MN., Division of Urology, Veterans Affairs Medical Center, Durham, NC., Department of Urology, UCLA School of Medicine, Los Angeles, CA., Urology Department, University of California San Diego Health System, San Diego, CA., 4r56y7up0-7y6t5ty7u8uDivision of Urology, Department of Surgery, Oregon Health and Science University, Portland, OR, USA., Department of Urology, UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA., Section of Urology, Veterans Affairs Medical Center, Augusta, GA.