Purpose: To examine retrospectively fractionated high-dose-rate brachytherapy as monotherapy for localized prostate cancer with special focus on tolerance and toxicity, especially chronic toxicity.
Materials and methods: Between May 1995 and October 2001, 43 patients with localized prostate cancer were treated with high-dose-rate brachytherapy without external beam irradiation at Osaka University Hospital. The stage was T1, T2, T3, and T4 in 8, 14, 18, and 3 patients, respectively. The adenocarcinoma was well, moderately, or poorly differentiated in 12, 16, and 15 patients, respectively. The median initial prostate-specific antigen level was 19.3 ng/mL (range 3.8-233.0). Thirty-eight patients also received hormonal therapy. Metallic needles were implanted transperineally under real-time ultrasound guidance, followed by a dose optimization program. Patients were irradiated twice daily at intervals of >6 h. A total dose of 54 Gy in nine fractions within 5 days (48 Gy in eight fractions within 5 days for the first 7 cases) was administered in one implant session. The median follow-up was 24 months (range 1-76).
Results: Radiation Therapy Oncology Group acute toxicity of Grade 4, 2, and 1 occurred in 1 (2%), 12 (28%), and 8 (19%) patients, respectively. Five patients had late toxicity: one with rectal ulcer (Grade 2) and four with rectal bleeding (Grade 1). The volume receiving 100% of the prescribed dose showed significant correlations with the incidence of acute and chronic toxicities (p = 0.005 and p = 0.014, respectively). The 3-year actuarial overall survival, local control, and biochemical no evidence of disease rate was 94%, 100%, and 55%, respectively. The crude biochemical control rate for low, intermediate, and high-risk patients was 100% (5 of 5), 80% (8 of 10), and 61% (17 of 28), respectively.
Conclusions: High-dose-rate brachytherapy as monotherapy was found to be feasible and well tolerated. It showed a low chronic toxicity rate without any event of Radiation Therapy Oncology Group of Grade 3 or greater.