Assessing radiation dose for postoperative radiotherapy in prostate cancer: Real world data

Area of Science:

• Oncology
• Radiation Oncology
• Urology

Background:

• Approximately 30% of prostate cancer (PCa) patients experience biochemical recurrence after radical prostatectomy.
• Postoperative radiotherapy (PORT) is a potentially curative option, but optimal dosing remains unclear.
• Limited data exists on the influence of PORT dose on patient outcomes.

Purpose of the Study:

• To investigate the impact of varying postoperative radiotherapy doses on biochemical failure-free survival (BFFS) in PCa patients.
• To evaluate secondary endpoints including overall survival (OS), cancer-specific survival (CSS), and metastasis-free survival (MFS).
• To assess treatment-related genitourinary (GU) and gastrointestinal (GI) toxicity.

Main Methods:

• Retrospective analysis of 301 PCa patients undergoing radical prostatectomy and PORT (adjuvant or salvage) between 2002 and 2015.
• Patients were grouped by total radiation dose: 66-68 Gy, 70 Gy, or 72 Gy.
• Kaplan-Meier and Cox regression analyses were used to assess survival outcomes and prognostic factors.

Main Results:

• No significant differences in 5- and 10-year BFFS rates were observed across the dose groups (69.6% vs. 80.5% vs. 82.6% at 5 years; P=0.12).
• Multivariate analysis identified biopsy Gleason score, clinical stage, and treatment indication as significant predictors of BFFS.
• Acute G1 GI toxicity was significantly lower in the 72 Gy group (5.6%) compared to the 66-68 Gy (29.6%) and 70 Gy (26.7%) groups (P=0.011).

Conclusions:

• Postoperative radiotherapy dose intensification to 72 Gy did not demonstrate superior efficacy compared to conventional doses (66-70 Gy) for BFFS in PCa.
• Conventional PORT doses appear sufficient, and dose escalation may not offer additional survival benefits.
• Further research may be warranted to explore optimal dosing strategies based on individual patient risk factors.