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

Abstract

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. 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. 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 > or =Grade 2 and > or =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 > or =Grade 2 and > or =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. 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.