Cancer - Prostate(구연) (E-106) 한국인 전이성 전립선암에서의 고위험군을 결정하는 적절한 뼈전이 숫자의 기준에 대한 연구 서울대학교 의과대학 비뇨의학교실 유상현, 윤현식, 정규환, 박대형, 이수빈, 김경훈, 서준교, 육형동, 정창욱, 김현회, 구자현, 곽철 Objective When clinicians define high volume metastatic prostate cancer(mPC), they usually used criteria from the CHAARTED trial or the LATTITUDE trial. These trials defined high volume mPC as the number of bone metastases, restpectively ≥4 and ≥3 of lesions. However, because these trials were mainly conducted in western countries, the criteria to define high volume group in Koreans may be different. Therefore we evaluated the suitable criteria of high volume mPC in Koreans. Material & Methods We analyzed 247 patients who initially diagnosed with metastatic prostate cancer (mPC) in Seoul National University Hospital from March 2000 to December 2019. All patients were treated with androgen depression therapy for initial treatment, and at the time of diagnosis, they had a wholebody PET-MRI or bone scan test. We reviewed the number of bone metastatic lesions in each patient, and analyzed how many bone metastatic lesions were suitable as a reference point for dividing the high and low risk groups of metastatic prostate cancer through Hazard Ratio(HR) smoothing. We used Kaplan-Meier survival analysis and Cox proportional risk model as a statistical analysis. Results Through HR smoothing, we found that if patients had more than 11 lesions, the HR of death had increased. Therefore, we divided two groups; bone lesions ≥11, high volume group; bone lesions ≤10, low volume group. When we analyzed the survival based on the modified criteria, the high volume group showed significantly lower survival rate than the low volume group in five-year progression free survival (20.3% vs. 49.3%, p<0.001) and five-year overall survival (36.2% vs. 56.7%, p<0.001). The high volume group showed statistically significant hazard ratio (HR) of the tumor progression and death (HR 2.01, 95% CI 1.35-2.99, p=0.001 and HR 2.29, 95% CI 1.51-3.49, p<0.001). The results obtained from the CHARRTED criteria and LATTITUDE criteria were as follows; CHARRTED: progression HR 1.53, 95% CI 0.90-2.59, p=0.117, death HR 1.43, 0.87-2.36, p=0.157; LATTITUED: progression HR 1.38, 95% CI 0.89-2.15, p=0.150, death HR 1.64, 95% CI 1.02-2.63, p=0.042. Conclusion In Koreans, the number of bone lesions to define the high volume in metastatic prostate cancer was different from those of previous trials. It may suggest additional information to set a treatment plan for metastatic prostate cancer. keywords : prostate cancer, bone metastasis, high volume