High-Dose-Rate Brachytherapy Plus External Beam Radiotherapy for T1 to T3 Prostate Cancer: An Experience in Taiwan

Objectives: To report outcomes for localized prostate cancer patients treated with the combination of high-dose-rate (HDR) brachytherapy and external beam radiotherapy (EBRT). Methods: Eighty-five Stage T1c to T3b prostate cancer patients treated with HDR brachytherapy plus EBRT were included. An HDR dose of 16.5 Gy in 3 fractions over 24 hours was given 2 weeks before EBRT. An EBRT dose of 50.4 Gy was administered to the prostate and seminal vesicles. Younger patients (aged less than 75 years) with greater than 15% risk of nodal metastasis received whole-pelvis RT (45 Gy in 25 fractions) as part of EBRT. Results: Fifty percent of patients belonged to the high-risk (T3a or Gleason score 8-10 or prostate-specific antigen greater than 20 ng/mL) or very-high-risk (T3b) groups. After a median follow-up of 49 months (range, 24 to 70 months), 4-year biochemical control survival (less than nadir + 2) was 86% (100%, 91%, and 81% for patients in the low, intermediate, and high-risk groups, respectively. Three of four T3b patients experienced early biochemical failure. Four patients (5%) had grade 3 implant-related urinary retention. Chronic gastrointestinal toxicities were limited, but four grade 3 chronic genitourinary toxicities (5%) were noted in relation to urethral stricture and severe hematuria. Whole-pelvis EBRT was a major contributing factor to acute but not to chronic gastrointestinal toxicities. Among 60 patients with pretreatment sexual potency, 17 (26%) retained capability after 4 years. Six patients (10%) lost potency merely as a result of salvage hormone therapy. Conclusions: High-dose-rate brachytherapy plus EBRT can achieve satisfactory biochemical control with acceptable complications for T1c to T3a prostate cancer patients.