International comparison in the Risk Calculator-based age-standardized incidence rate of prostate cancer between Japan and the Netherlands

Introduction & Objectives: Objective comparison in the risk of developing prostate cancer among different regions around the world is very difficult because of differences in e.g. the reliability of the cancer registry and penetration of PSA screening. Risk Calculator (RC)-based age-standardized incidence rates (AIR)of prostate cancer (PC)could be a simple and objective method to assess a comparable probability of PC among countries having the availability on population-based PSA data (Int J Cancer 2018 Apr 26. doi: 10.1002/ijc.31560). In the present study, the AIR was compared between Gunma, Japan and Rotterdam, the Netherlands. Materials & Methods: The Gunma cohort consisted of 72,654 men aged 50 to 79 who underwent first time PSA screening between 1992 and 2016 in a population-based screening program. The Dutch cohort consisted of 19,967 men, same age range who participated in the first round of PSA screening (1993-1999)in ERSPC section Rotterdam. The probabilities of PC and clinically significant PC (CSPC)in both regions were estimated by the Rotterdam Prostate cancer Risk Calculator 3 using individual PSA data. Then, RC-based AIR of PC and AIR published in epidemiological surveys was compared between two regions (Trial No: UMIN000029069). Results: The AIR of PC published in the epidemiological surveys in Japan and the Netherlands, respectively, were 5 and 39 (7.7 times difference)in 1975, 8 and 44 (5.5 times difference)in 1985, 12 and 90 (7.5 times difference)in 1995, 28 and 100 (3.6 times difference)in 2005. The changes in the RC-based AIR of PC in Gunma between 1992 and 2016 are shown in the Figure. The RC-based AIR of PC in Gunma was 1,709 (per 100,000 men)in average and fluctuated slightly between 1,556 and 1,839 throughout the 25 years. The RC-based AIR of CSPC was 600 in average and was stable between 542 and 672 throughout the 25-year period. The RC-based AIR of PC and CSPC in men participated in the first round of ERSPC, Rotterdam were 2,138 and 834, which was 1.25 and 1.39 times higher than the corresponding RC-based AIR in Gunma. [Figure presented]Conclusions: Differences in the base line risk of developing PC or CSPC between Japan and the Netherlands could actually be less than previously notified in epidemiological data based on cancer registries. A RC-AIR on the basis of population-based PSA data could be useful to determine national future perspectives on PC management.