Do differences in secondary treatment explain mortality impact of prostate cancer screening? - A randomized screening trial.

[BACKGROUND] The European Randomized study of screening for prostate cancer (ERSPC) demonstrated a reduction in prostate cancer (PC) mortality via PSA-based screening. We evaluated whether treatments for castration resistant PC vary between the trial arms within the Finnish section (FinRSPC) of the ERSPC.

[METHODS] Clinical data were collected from medical records and national health care databases for all men diagnosed with PC and starting androgen deprivation therapy (ADT) during 1996-2015 at Tampere University Hospital. We evaluated frequencies and durations of treatments for castration resistant PC. Cox regression was used to assess time from ADT initiation to castration resistant PC treatment.

[RESULTS] In total, 62 (14.2%) and 116 (15.9%) received at least % cycle of treatment for castration resistant PC in the screening and control-arm, respectively. There were no statistically significant differences in distribution of treatments for castration resistant PC between the study arms at any treatment lines (P-values over 0.05 for first, second and third & later lines of treatment). No difference was found in time to initiation of treatment for castration resistant PC after ADT. (HR: 1.00; 95% [CI], 0.78-1.39; P = 0.998).

[CONCLUSIONS] Although limited by small sample size and a single-center scope, our findings suggest the mortality result of the FinRSPC is not attributable to differing treatment for castration-resistant PC between the trial arms.