3341 - Long Term Metastasis-Free Survival of a Nationwide Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS) Study
Presenter(s)
Y. Shiraishi1,2, N. Tanaka II3, S. Kojima4, T. Kikuchi4, H. Ishiyama5, K. Miki6, I. Asakawa7, K. Kikuchi8, H. Ikushima9, M. Eto10, Y. Hamamoto11, Y. Kageyama12, K. Iijima13, M. Kaidu14, K. Nakamura15, K. Yamada16, A. Yorozu2, and S. Saito17; 1Department of Radiology, Keio University School of Medicine, Tokyo, Japan, 2Department of Radiation Oncology, National Hospital Organization, Tokyo Medical Center, Tokyo, Japan, 3Department of Urology, Nara Medical University, Kashihara, Japan, 4Translational Research Center for Medical Innovation, Kobe, Japan, 5Department of Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan, 6Jikei University School of Medicine, Tokyo, Japan, 7Department of Radiation Oncology, Nara Medical University, Kashihara, Japan, 8Iwate Medical University School of Medicine, Morioka, Japan, 9Tokushima University, Tokushima, Japan, 10Kyushu University School of Medicine, Fukuoka, Japan, 11Dept. of Radiation Oncology, Shikoku Cancer Center Hospital, Matsuyama-city, Ehime, Japan, 12Saitama Cancer Center, Saitama, Japan, 13Nagano Municipal Hospital, Nagano, Japan, 14Department of Radiation Oncology, Niigata University Medical and Dental Hospital, Niigata, Japan, 15Department of Radiation Oncology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan, 16Department of Radiation Oncology, Seirei Mikatahara General Hospital, Hamamatsu, Japan, 17Ofuna Chuo Hospital, Kamakura, Japan
Purpose/Objective(s): The nationwide Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS) was performed since July 2005 to December 2007 to evaluate the safety and efficacy in patients with prostate cancer (PCa) who underwent low-dose-rate brachytherapy (LDR-BT). We conducted a follow-up study (J-POPS2) in order to investigate the long-term survival and oncologic outcomes, especially overall survival (OS) and metastasis-free survival (MFS), which is a strong surrogate of OS in localized PCa.
Materials/Methods: Of the 6,927 cases registered with J-POPS, 3,509 cases that were able to follow-up were included in this follow-up study. The primary endpoint of this study is OS. We analyzed MFS as one of the secondary endpoints. Log rank test and Cox regression model were used for survival analyses.
Results: The age range of participants was 38 to 89 years (median: 68 years) and their risk classifications according to the National Comprehensive Cancer Network (NCCN) were 1388 (42.8%) at low-risk, 1640 (50.6%) at intermediate-risk, 213 (6.6%) at high-risk. Of all patients, 799 patients (22.7%) treated with external beam radiation therapy, 1425 patients (40.6%) received androgen-deprivation therapy (ADT), and 319 (9.1%) received adjuvant ADT. The median follow-up period was 11.8 years. The 5-year, 10-year and 15-year OS rate were 99.8%, 93.6% and 79.0%, respectively. The 10-year OS rate of low, intermediate, and high risk were 94.6%, 92.9%, and 91.7%, respectively (P=0.016). The 5-year, 10-year and 15-year MFS rate were 98.0%, 92.0% and 75.4%, respectively. The 10-year MFS rate of low, intermediate, and high risk were 93.5%, 88.2%, and 82.8%, respectively (P<0.001). Age older than 65 years old (P<0.001), Gleason score (P<0.001) and PSA level (P=0.001) were significant factors predicting MFS. On multivariate analysis, age older than 65 years old (HR 2.54 [95% CI 1.702-3.782]) and neoadjuvant ADT (HR 1.46 [95%CI 1.065-2.003]) were significant factors predicting MFS in low risk patients. Age older than 65 years old (HR 2.02 [95% CI 1.466-2.796]) and PSA level (HR 1.59 [95%CI 1.124-2.245]) were significant factors predicting MFS in intermediate risk patients. PSA level (HR 1.97 [95%CI 1.064-3.662]) and Gleason score (HR 2.45 [95%CI 1.294-4.643]) were significant factors predicting MFS in high risk patients. The biological effective dose (BED) was not a significant predicting factor for MFS in each risk group.
Conclusion: This is the world's largest registration study in patients with PCa who underwent LDR-BT with long follow-up period. The long-term excellent survival and oncologic outcomes could be confirmed in this prospective Japanese patient cohort study. Considering metastases were found even after 10 years from implantation in some patients, long term follow-up should be recommended.