Single Fraction High Dose Rate Brachytherapy and Two Schemes of External Radiotherapy for Prostate Adenocarcinoma

Abstract

rate (HDR) brachytherapy followed by 5 weeks of external beam radiation therapy. We have treated over 400 patients to-date and this is a retrospect review of the techniques and outcome. We also did a preliminary comparison of our two different HDR regimens used over the years. Materials and Methods: Before April of 2011, we treated all our patients with a single brachytherapy procedure and delivered a nominal dose of 18 Gy given in 3 fractions over 24 hours. (Group 1) All patients needed to be hospitalized overnight. One treatment was delivered in the afternoon of the procedure and two additional fractions were given on the following day. The interval between sessions was at least 6 hours. Since April, 2011, all HDR brachytherapy patients were treated on an outpatient basis with one single fraction of 13 Gy. (Group 2) We are using the GammaMed Plus unit with BrachyVision software for dosimetry planning and treatment delivery. Hormone therapy, usually LH-RH agonist was given for a minimum of 6 months starting about 2 to 3 months prior to radiation therapy. After the HDR procedure, all patients received external beam therapy to a total dose of 45 to 50 Gy being delivered over a period of 5 weeks using conformal, IMRT or arc technique. Planning Tumor Volume usually depended on Gleason pathology. Results: The median follow-up of our Group 1 patients was 60 months and the follow-up of our Group 2 patients remains too short for analysis. Thus far all our 27 Group 2 patients are doing well without apparent evidence of treatment failure or complications. There were a total of 405 patients in Group 1 and the outcome was favorable considering all had intermediate or high risk disease. Biochemical control was achieved in 340 patients (84%) Seventeen (17) patients died from metastatic disease and 15 patients are alive with metastatic disease. Twenty-three (23) patients demonstrated biochemical failure without clinical evidence of local or distant disease. Sixty-five (65) patients died from unrelated causes without evidence of prostate cancer. The most significant radiation related complication was urethral stricture which occurred in 23 patients (6%). However, only 3 patients required urinary diversion. Conclusions: HDR Brachytherapy appears effective in the treatment of clinically localized intermediate or high risk prostate cancer. Single dose HDR is appealing because of patient convenience and hospital savings. Most significantly it eliminates the risk of inter-fraction displacement of brachytherapy catheters. The results are encouraging, but further followup will be necessary.