The seven-year preliminary results of brachytherapy with Iodine-125 seeds for localized prostate cancer treated at a Brazilian single-center

ABSTRACT

OBJECTIVE: To report the seven-year preliminary results of a single-center on brachytherapy with Iodine-125 seeds, used in combination with external beam radiotherapy in selected patients with localized prostate cancer (T1-T2). MATERIALS AND METHODS: All 105 patients treated by brachytherapy with Iodine-125 seeds, from January/1998 to December/2004, were retrospectively analyzed. The prescribed dose was 144 Gy at the periphery of the prostate for isolated brachytherapy, and 110 Gy for the combination with external beam radiotherapy. The external beam radiotherapy dose was 45 Gy, at the prostatic bed. Neoadjuvant hormone therapy was indicated for selected patients, who received luteinizing hormone-releasing hormone (LH-RH) and/or antiandrogens. For definition of biochemical relapse, it was adopted the American Society for Therapeutic Radiology and Oncology consensus. RESULTS: Of the 105 patients treated, 90 were followed for a mean period of 70 months. Biochemical disease control was achieved in 62 (69 percent) and biochemical recurrence was manifested in 28 (31 percent). The analysis of each risk group showed biochemical disease control rates of 79 percent, 71 percent and 52 percent in the low, intermediate and high risk groups, respectively. The mean time for biochemical recurrence was 22 months. Genitourinary acute toxicity was classified as grade 0-2 (RTOG) in 88.5 percent and in 94.2 percent for the late toxicity (RTOG/EORTC). Gastrointestinal acute toxicity was graded as 0-2 (RTOG) in 100 percent and in 97.7 percent for the late morbidity. No grade 5 was detected. CONCLUSIONS: Brachytherapy with Iodine-125 seeds is an effective alternative treatment for early stage prostatic cancer, with good biochemical disease control rates and low to moderate toxicity. The best results were obtained in low and intermediate risk patients.