Positive prostate biopsy following radiotherapy can predict metastasis-free survival in localized prostate cancer.

To determine the impact of post-treatment biopsy results on 10-year metastasis-free survival (MFS), overall survival (OS) and cause-specific survival (CSS) in localized prostate cancer (PCa) patients treated with high-dose radiotherapy (RT).

Retrospective analysis of 232 patients with T1c-T3bN0M0 PCa who underwent a prostate biopsy 24-36 months after high-dose RT. Biopsies were categorized as positive biopsy (PB) if H&E staining showed evidence of residual malignancy and negative biopsy (NB) if no malignant cells were present. Kaplan-Meier estimates of 10-year MFS, OS and CSS rates were calculated for each group and Cox proportional-hazards models were used to estimate the hazard ratios. The median follow-up was 124 months (range 26-267).

Sixty-two of 232 (26.7%) patients had post-treatment positive biopsies (PB). A positive post-treatment biopsy was significantly associated with a lower 10-year MFS (78.4% vs. 95.4%, p = 0.001, HR: 3.9, 95% CI: 1.8-8.3). Although patients with PB had worse outcomes that those with NB, we could not show a statistically significant difference in OS (81.0% vs. 87.9%, p = 0.282, HR: 1.3, 95% CI: 0.7-2.3) or CSS (96.2% vs. 99.4% (p = 0.201, HR. 2.4, 95% CI: 0.6-9.7). After multivariate analysis, the strongest predictor of MFS was the post-treatment biopsy status (p < 0.001, HR: 5.4, 95% CI 2.26-12.85) followed by Gleason score (p = 0.002, HR: 2.24, 95% CI 1.33-3.79).

A positive biopsy following RT can predict MFS in localized prostate cancer. These data highlight the relevance of achieving a local control and support the use of aggressive local therapeutic interventions for PCa.

Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology. 2019 Dec 09 [Epub]

A Zapatero, M Adrados, L Torres, M S Talaya, A Cruz Conde, C Martin de Vidales, L Vega Piris, C Olivier, M T Murillo

Department of Radiation Oncology, Hospital Universitario de la Princesa, Madrid, Spain., Department of Pathology, Hospital Universitario de la Princesa, Madrid, Spain., Methodologic Unit Health Research Institute, Hospital Universitario de la Princesa, Madrid, Spain., Department of Urology, Hospital Universitario de la Princesa, Madrid, Spain.