Comparison of the outcome and morbidity for localized or locally advanced prostate cancer treated by high-dose-rate brachytherapy plus external beam radiotherapy (EBRT) versus EBRT alone

Objective: To compare the survival, gastrointestinal (GI) and genitourinary (GU) toxicity for localized or locally advanced prostate cancer treated by high-dose-rate-brachytherapy (HDR-BT) plus external beam radiotherapy (EBRT) versus EBRT alone at a single institute in Taiwan. Methods: Eighty-eight patients with T1c-T3b prostate cancer consecutively treated by EBRT alone (33 patients) or HDR-BT+EBRT (55 patients) were studied. The median dose of EBRT was 70.2 Gy in the EBRT group and 50.4 Gy in the HDR-BT group. HDR-BT was performed 2-3 weeks before EBRT, with 12.6 Gy in three fractions over 24 h. Results: Five patients (15.2%) in the EBRT group and seven (12.7%) in the HDR-BT group developed a biochemical relapse. The 5-year actuarial biochemical relapse-free survival rates were 65.0% in the EBRT group and 66.7% in the HDR-BT group (P = 0.76). The 5-year actuarial likelihood of late >= Grade 2 and >= Grade 3 GI toxicity in the EBRT versus HDR-BT group was 62.8 versus 7.7% (P < 0.001) and 19.6 versus 0% (P = 0.001), respectively. In a multivariate analysis, the only predictor for late GI toxicity was the mode of RT. The 5-year actuarial likelihood of late >= Grade 2 and >= Grade 3 GU toxicity in the EBRT versus HDR-BT group was 14.8 versus 15.9% (P = 0.86) and 3.6 versus 8.5% (P = 0.40), respectively. Conclusions: The addition of HDR-BT before EBRT with a reduced dose from the EBRT produces a comparable survival outcome and GU toxicity but a significantly less GI toxicity for prostate cancer patients.