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Prostate cancer incidence rates are much lower in Japan than in Western Europe and the USA. However, because of rapid aging, increasing “Westernization,” and the frequent use of the serum prostate‐specific antigen test for prostate cancer, the age‐adjusted incidence rate of prostate cancer has increased approximately 6.5 times from 1975 to 2008 and remains high today. The number of new cases was estimated to account for 51 500 in 2008 in Japan.
Atomic bomb survivors have been reported to have an increased risk of many solid cancers, including lung cancer and colon cancer. However, the risk of prostate cancer in atomic bomb survivors has not been previously reported, although the risks for bladder cancer, which involves the same urinary organ, and breast cancer, which is considered to share some biological and epidemiological features, are reported. The small number of prostate cancer cases detected is a plausible reason for these inconsistent results.
In this study, we examined whether atomic bomb radiation affected the incidence of prostate cancer among Nagasaki atomic bomb survivors. To our knowledge, this report is the first to examine the association between atomic bomb radiation and prostate cancer after its incidence began to increase.
The subjects were Nagasaki atomic bomb survivors registered since 1973 at the Atomic Bomb Disease Institute, Nagasaki University (Nagasaki, Japan), which was established in 1972. In the present study, an “atomic bomb survivor” was defined as a person who received the “Atomic Bomb Survivor's Health Handbook” authorized by Nagasaki City. The Atomic Bomb Disease Institute maintains computerized records of data on the handbook holders. Information on these survivors, including changes in address and date of death, has been updated monthly with the cooperation of the Department for Atomic Bomb Survivors’ Affairs, Nagasaki City Hall. The registered cases include directly exposed persons, those not present in Nagasaki City at the time of bombing but entering the city soon after the bomb (within 2 weeks), those in the rescue services, and fetuses. In this study, the incidence of prostate cancer was evaluated in residents of Naga‐saki City who were directly exposed or who entered the city soon after the bomb explosion, those who were confirmed alive in 1996, and those whose smoking and alcohol consumption habits...