Prostate Cancer Diagnosis by Transurethral Resection of the Prostate Is Associated with Compromised Oncologic Outcomes Post-Prostatectomy

<b>Background:</b> Following transurethral resection of the prostate (TURP) for lower urinary tract symptoms, incidental diagnosis of prostate cancer occurs in 2-10%. The significance of incidental prostate cancer on TURP compared to diagnosis via traditional diagnostic pathways is unclear. We aimed to compare post-prostatectomy outcomes in patients diagnosed with prostate cancer on TURP and prostate biopsy, using a population-based clinical quality registry. <b>Methods:</b> Data were extracted from the Victorian Prostate Cancer Outcomes Registry (PCOR-Vic). Patients who underwent prostatectomy between September 2008 and September 2020 and who were diagnosed by needle biopsy or TURP were included. The association between diagnosis method and overall survival was examined with Kaplan-Meier plots and the log-rank test. Multivariable Cox proportional hazards regression adjusting for PSA, age, year of surgery, diagnostic Gleason grade group and margin status was also used. Association with prostate cancer-specific mortality was examined with Fine and Gray competing hazards regression including the same covariates as above. <b>Results:</b> In total, 12022 patients met the inclusion criteria, of which 159 (1.3%) were diagnosed on TURP. After a median 58 months follow-up, diagnosis on TURP was associated with poorer 5-year overall survival at 91.2% (84.2-95.0%) compared to diagnosis on needle biopsy at 96.7% (96.2-97.0%), log-rank <i>p</i> = 0.001. Following multivariable adjustment, the hazard ratio of TURP vs. biopsy patients was 2.33 (95%CI: 1.35-4.01). For prostate cancer-specific mortality, there was a similar estimate; however, the 95% confidence interval crossed one, subHR = 2.24 (95% CI: 0.77-6.57). <b>Conclusions:</b> Diagnosis of prostate cancer on TURP was associated with poorer overall survival when compared to men diagnosed on prostate biopsy. These findings have clinical implications given the increased use of photoselective vaporisation of the prostate, which is characterised by the lack of pathologic tissue for assessment.