Two-years Postradiotherapy Biopsies: Lessons from MRC RT01 Trial

Area of Science:

• Oncology
• Radiotherapy
• Urology

Background:

• The clinical significance of prostate biopsies conducted two years after radiotherapy remains unclear.
• Assessing the utility of these biopsies is crucial for refining treatment strategies.

Purpose of the Study:

• To evaluate the prognostic value of two-year post-radiotherapy prostate biopsies in a randomized trial.
• To determine the association between biopsy results and long-term oncological outcomes.

Main Methods:

• A randomized trial involving 843 men with localized prostate cancer receiving conformal radiotherapy (CFRT) with or without dose escalation.
• Prostate biopsies were performed at two years post-CFRT in eligible patients.
• Outcomes, including biochemical progression-free survival (bPFS) and overall survival, were analyzed using a landmark approach from the two-year biopsy.

Main Results:

• A positive two-year biopsy was strongly prognostic of worse bPFS (HR=4.81).
• Elevated prostate-specific antigen (PSA) levels (1.01-2.09 ng/ml) at two years were associated with increased risk of PSA failure, bPFS events, and prostate cancer-specific survival.
• Routine biopsies showed limited value in patients with PSA control.

Conclusions:

• Two-year postradiotherapy biopsies have limited value when PSA levels are controlled.
• Positive biopsy results and elevated PSA levels are significant predictors of future bPFS events.
• Selective biopsy in patients with unfavorable PSA may facilitate early salvage interventions.