3-D conformal HDR brachytherapy as monotherapy for localized prostate cancer -: A pilot study

Purpose: Pilot study to evaluate feasibility, acute toxicity and conformal quality of three-dimensionaL (3-D) conformal high-dose-rate (HDR) brachytherapy as monotherapy for Localized prostate cancer using intraoperative real-time planning. Patients and Methods: Between 05/2002 and 05/2003, 52 patients with prostate cancer, prostate-specific antigen (PSA) less than or equal to 10 ng/mL, Gleason score less than or equal to7 and clinical stage less than or equal to T2a were treated. Median PSA was 6.4 ng/mL and median Gleason score 5. 24/52 patients had stage T1c and 28/52 stage T2a. For transrectal uLtrasound-(TRUS-)guided transperineal. implantation of flexible plastic needles into the prostate, the real-time HDR planning system SWIFT(R) was used. After implantation, CT-based 3-D postplanning was performed. All patients received one implant for four fractions of HDR brachytherapy in 48 h using a reference dose (D-ref) of 9.5 Gy to a total dose of 38.0 Gy. Dose-volume histograms (DVHs) were analyzed to evaluate the conformal quality of each implant using D-90, D-10 urethra, and D-10 rectum. Acute toxicity was evaluated using the CTC (Common Toxicity Criteria) scales. Results: Median D-90 was 106% of D-ref (range: 93-115%), median D-10 urethra 159% of D-10 (range: 127-192%), and median D-1, rectum 55% of D-ref (range: 35-68%). Median follow-up is currently 8 months. In 2/52 patients acute grade 3 genitourinary toxicity was observed. No gastrointestinal toxicity > grade 1 occurred. Conclusion: 3-D conformal HDR brachytherapy as monotherapy using intraoperative real-time planning is a feasible and highly conformal treatment for Localized prostate cancer associated with minimal acute toxicity. Longer follow-up is needed to evaluate late toxicity and biochemical control.