Low-Dose-Rate Brachytherapy for Low- and Intermediate-Risk Groups of Localized Prostate Cancer

ABSTRACT

PURPOSE: We applied low-dose-rate brachytherapy for low- and intermediate-risk groups of prostate cancer patients. Our initial experiences were analyzed to assess the result of low-dose-rate brachytherapy for low- and intermediate-risk groups of patients with localized prostate cancer. MATERIALS AND METHODS: A total of 50 consecutive patients have been treated with brachytherapy for 1 year since April 2007. Among them, a total of 24 patients in the low- or intermediate-risk groups were enrolled 10 of the 24 patients were in the low-risk group (clinical T1a-T2b, Gleason score [GS] of 2-6, PSA<10 ng/ml), and 14 patients were in the intermediate-risk group (clinical T2b-T2c, Gleason score of 7, or PSA 10-20 ng/ml). Implantations were performed by practicing a real-time ultrasound-guided placement including prostatic capsular placement in the intermediate-risk group. All 24 patients were treated with 1 to 3 months of androgen-deprivation therapy. RESULTS: In the low- and intermediate-risk groups, the median patients' ages were 64 and 70 years, respectively. The numbers of patients in the low-risk group according to clinical T stage were 4 cases of T1c and 6 cases of T2a. The intermediate-risk group included 4 patients of stage T2a, 3 patients of stage T2b, and 7 patients of T2c. Five patients with a GS< or =6 and 9 patients with a GS of 7 were classified as being in the intermediate-risk group. Serum PSA levels in the intermediate-risk group were less than 10 ng/ml in 11 patients and 10-20 ng/ml in 3 patients. The median radiation doses delivered to 90% of the prostate in the low-risk and intermediate-risk groups were 257.5 Gy (range, 142.5-357.5 Gy) and 260.0 Gy (range, 147.5-357.5 Gy), respectively. Biochemical failure was not revealed in any case during follow-up. No patients experienced major complications. CONCLUSIONS: We can expect outstanding local control effect with low-dose-rate brachytherapy in low- and intermediate-risk prostate cancer. Our technique of modifying the insertion field in the intermediate-risk group is feasible and tolerable. However, long-term follow-up data are needed for this strategy.