Canadian guidelines define castration-resistant prostate cancer (CRPC) at high risk of developing metastases using PSA doubling time (PSADT) < 8 months, whereby men may be offered more frequent bone scans/imaging.

We evaluated PSA data from nonmetastatic (M0) prostate cancer patients treated at urology and oncology clinics across the United States (US) to describe the proportion and characteristics of patients who met CRPC and high-risk criteria.

We identified M0 prostate cancer patients aged = 18 years receiving androgen deprivation therapy (ADT) in 2011 from electronic health records (EHR), covering 129 urology and 64 oncology practices across the US. We estimated the proportion of prostate cancer patients with evidence of CRPC (consecutive rising PSAs) and subsets that may be at high risk (using several PSA and PSADT cut-points).

Among 3121 M0 prostate cancer patients actively treated with ADT, 1188 (38%) had evidence of CRPC. Of these, 712 (60%) qualified as high risk in 2011 based on PSADT < 8 months (equivalent to = 8 months in these data). Men = 65 years were more likely to have evidence of CRPC than younger men, although younger men were more likely to have evidence of high-risk disease. CRPC was more common among men receiving ADT in the oncology setting than the urology setting (48% versus 37%).

In this large EHR study with patient-level PSA data, 38% of men with M0 prostate cancer treated with ADT had CRPC. Approximately 60% of M0 CRPC patients may experience a PSADT of < 8 months. These findings require validation in a Canadian patient population.

The Canadian journal of urology. 2015 Aug [Epub]

Rohini K Hernandez, Karynsa Cetin, Melissa Pirolli, Jane Quigley, David Quach, Paul Smith, Scott Stryker, Alexander Liede

Center for Observational Research, Amgen Inc., Thousand Oaks, California, USA.