Prevalence and Natural History of Non-metastatic Castrate Resistant Prostate Cancer: A Population-Based Analysis

Purpose: To determine the prevalence and natural history of nmCRPC prior to the adoption of novel androgen receptor axis-targeting therapies(ARAT).

Materials and methods: This was a retrospective population-based cohort study of men with nmCRPC in Ontario, Canada between January 2007-March 2018. Patients with prostate cancer, castrate level of testosterone(<1.7nmol/L) and a PSA>2.0ng/mL with a subsequent rise>25% from the nadir, and without metastasis were included. Annual prevalence of nmCRPC was calculated. Crude time from nmCRPC to metastasis and all-cause death are presented as medians with interquartile range(IQR). Predictors of time from nmCRPC to death were compared using univariable and multivariable cox proportional hazard models.

Results: We identified 2045 patients with nmCRPC. Median age was 79(IQR:72-84). 984 patients(48.1%) received upfront hormonal therapy while 583(28.5%) received initial radiotherapy and 478(23.4%) underwent radical prostatectomy. Median time from primary treatment to nmCRPC was 6 years(IQR:3-10). The average annual prevalence of nmCRPC was 8% among men receiving ADT. Crude median time from nmCRPC to death was 37.6 months(IQR:22.1-55.4). Median time from nmCRPC to metastasis and metastasis to death was 20.0 and 8.3 months, respectively. Patients who had primary surgery experienced longer crude survival. Older patients, patients who had a higher PSA at nmCRPC, and patients with grade group 4 to 5 disease had a shorter time from nmCRPC to death.

Conclusion: This is the largest population-level analysis of the prevalence and natural history of nmCRPC. The current study can be used as a historical cohort to compare how novel imaging modalities and ARAT impact prevalence and disease trajectory over time.