Predictors of Time to Metastasis in Castration-Resistant Prostate Cancer.

To investigate predictors of time to metastasis among men treated with androgen deprivation therapy (ADT) for non-metastatic prostate cancer who developed castration-resistant prostate cancer (CRPC) within the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort.

Retrospective analysis of 458 non-metastatic CRPC men. Metastases were detected in routine bone scans or other imaging tests. Predictors of time to metastasis were analyzed using proportional hazards model with CRPC as time zero.

A total of 256 (56%) men were diagnosed with metastatic disease over a median follow-up of 36 months. Metastasis-free survival was 79%, 65%, 52%, 47% and 41% at 1, 2, 3, 4 and 5 years after CRPC, respectively. In multivariable analysis, Gleason score 8-10 (HR=1.61; P=0.026), receiving primary localized treatment (HR=1.38; P=0.028), higher PSA levels at CRPC diagnosis (logPSA HR=1.64; P<0.001) and PSA doubling time ≤6 months (HR=1.42; P=0.040) were independently associated with shorter time to metastasis. Race, year of CRPC, age and time from ADT to CRPC were not associated with metastasis.

Among non-metastatic CRPC men, nearly 60% developed metastatic disease during the first 5 years with most of the metastasis occurring within the first 3 years. Higher Gleason score, receiving primary treatment, higher PSA and shorter PSA doubling time were independently associated with shorter time to metastasis. Therefore, these variables can be used to stratify patients according to metastasis risk.

Urology. 2016 Jun 15 [Epub ahead of print]

Daniel M Moreira, Lauren E Howard, Katharine N Sourbeer, Hiruni S Amarasekara, Lydia C Chow, Dillon C Cockrell, Brian T Hanyok, William J Aronson, Christopher J Kane, Martha K Terris, Christopher L Amling, Matthew R Cooperberg, Alex Liede, Stephen J Freedland

Department of Urology, Mayo Clinic, Rochester, MN. Electronic address: ., Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC; Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Veterans Affairs Medical Center Durham, NC., Urology Section, Department of Surgery, Veterans Affairs Medical Center, Greater Los Angeles, Los Angeles, CA; Department of Urology, University of California at Los Angeles Medical Center, Los Angeles, CA., Division of Urology, Department of Surgery, University of California at San Diego Medical Center, San Diego, CA., Urology Section, Division of Surgery, Veterans Affairs Medical Centers and Division of Urologic Surgery, Department of Surgery, Medical College of Georgia, Augusta, GA., Division of Urology, Department of Surgery, Oregon Health & Science University, Portland, OR., Departments of Urology and Epidemiology & Biostatistics, University of California, San Francisco and Urology Section, Department of Surgery, Veterans Affairs Medical Center, San Francisco, CA., Amgen Inc., Urology Section, Veterans Affairs Medical Center Durham, NC; Division of Urology, Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA, USA.