Japanese prostate cancer outcome study of permanent I-125 seed implantation (J-POPS study): Interim results of a prospective cohort study assessing efficacy, safety and QOL

Abstract

16137 Background: Brachytherapy with permanent iodine-125 (I-125) seed implantation has been approved in Japan in July 2003. Multi-institutional cohort study (J-POPS study) assessing the treatment feature, efficacy, safety and health related quality of life (QOL) has begun in July 2005. Over 2,700 patients from 49 institutes are enrolled in this study until the end of October 2007 and finally 8,000 patients in total is expected to be enrolled until the end of 2010. The interim results of this ongoing study have been evaluated. Methods: Forty-three institutions combined data on 1,217 cases treated between July 2005 and February 2007 are analyzed for this interim study. Patient’s background, cancer character, treatment feature such as combined therapy of external beam or hormone, post implantation dosimetric information, treatment efficacy with PSA level, voiding symptoms with IPSS and treatment related adverse events according to NCI- CTCAE are characterized. PSA was measured every 3 months and symptoms accompanied to the treatment were assessed 3 and 12 months after the treatment. The primary end point of the study is biochemical or clinical failure. Results: Average age was 67.8 and 99.2% of the cases were performance status (PS) 0. PSA level on cancer diagnosis was 2.48 to 260 (mean 7.04) ng/ml, clinical stage T2a or less was in 89.56%, T2b-T2c in 9.78%, and T3a-T3b in 0.66%. Gleason score less than 7 was in 52.5%, 7 in 43.3%, and above 7 in 4.2%. Preoperative hormone therapy was performed in 53.16% and external beam (total dose of 45 Gy) was combined in 28.4%. CT based first post therapeutic month dosimetry revealed that prostatic mean V100 and D90 for the cases treated with seed alone were 94.7% and 161.2 Gy, respectively. As for adequate control of radiation dose at rectum (mean R100 = 0.28 cc) and urethra (mean D5 = 220 Gy), toxicities at 3 month over grade 3 was 0%, and grade 3 toxicity was seen only in miction pain (0.26%), pollakisuria or urgency (0.38%), and dysuria (0.38%). Only toxicity over grade 2 seen at 12 month was dysuria (2.14%). Conclusions: Nationwide cohort study for prostate brachytherapy has been executed in Japan to clarify the racially original evidence of the treatment. No significant financial relationships to disclose.