Clinical characteristics and prostate-specific antigen kinetics of prostate cancer detected in repeat annual population screening in Japan

Objectives To clarify the present status regarding repeat examination in the annual population screening system in Japan, and to analyze the clinical characteristics and prostate-specific antigen kinetics of prostate cancer detected in this setting. Methods We summarized the annual individual data of prostate-specific antigen-based population screening in Kanazawa, Japan, and analyzed the prostate cancer detection rates at first and repeat screening. The clinical characteristics were compared between patients detected at first and repeat screening. The patients were classified according to favorable or unfavorable clinical characteristics of cancer, and prostate-specific antigen kinetics were compared between the two groups. Results From 2000 to 2011, 19 620 men participated in this screening program, and a total of 59 019 screenings were carried out. The total annual numbers of examinees increased, and the annual rates of first examinees gradually decreased. The annual detection rates of cancer at total screening decreased in the second year. The annual detection rate at first screening was not different from that in the first year. The rate of patients with favorable cancer features was significantly higher among patients detected at repeat screening than at first screening. The rates of patients with high prostate-specific antigen velocity and low prostate-specific antigen doubling time were significantly higher in unfavorable than favorable cancer patients in repeat screening. Conclusions Repeat population screening could contribute to early detection of prostate cancer, and it seems that prostate-specific antigen kinetics might predict the cancer characteristics in repeat screening.