Electronic Thesis and Dissertation Repository


Master of Science


Epidemiology and Biostatistics


Dr. George Rodrigues


Purpose: This study compares overall survival (OS) and biochemical failure-free survival (bFFS) in low- and intermediate-risk prostate cancer patients that received brachytherapy [low-dose-rate brachytherapy (LDR-BT) or high-dose-rate brachytherapy with external beam radiation therapy (HDR-BT+EBRT)] versus external beam radiation therapy (EBRT) alone.

Materials/Methods: Patient data was obtained from the ProCaRS database, which contains 7974 prostate cancer patients treated at four Canadian institutions. Propensity score (PS) matching was used to generate matched cohorts with balanced baseline prognostic factors.

Results/Conclusions: Final PS matches included two 1:1 intermediate-risk patient matches, LDR-BT vs. EBRT (total n = 254) and HDR-BT+EBRT vs. EBRT (total n=388), and a 4:1 (LDR-BT:EBRT) low-risk match (total n=400). Hazard ratios for OS were 0.79 (p=0.69), 0.64 (p=0.47), and 1.41 (p=0.50), respectively. Hazard ratios for bFFS were 0.22 (p=0.001), 0.48 (p=0.007), and 0.35 (p=0.004), respectively.

Conclusions: PS matching showed BT significantly improved bFFS but not OS in matched prostate cancer patients.