Chronological and regional differences of testicular cancer--epidemiological analysis of incidence in gunma prefecture and estimated data of national survey, and of death in Japan

Abstract

The incidence of testicular cancer is rare. However, it is a significant cancer in that it develops not only in old age but also in children and younger age. We investigated the epidemiological characteristics of testicular cancer in Japan, in order to elucidate its features and problems. We surveyed hospitals and clinics in and around Gunma prefecture that treated patients with urologic diseases and reviewed the pathology records from 1985 to 1994, and calculated the annual age-adjusted incidence rates of testicular cancer. Incidence rates in Japan were taken from the estimates made by 'The Research Group for Population-based Cancer Registration in Japan'. The annual number of deaths, annual age-adjusted death rates from 1947 and 1998, the age-specific death rates and decrease rate of them, and the prefectural standardized mortality ratio (SMR) from 1973 and 1998 was calculated from the data reported by Ohno et al. and statistical tables kept in 'Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare'. In Gunma Prefecture, the annual age-adjusted incidence rates tended to increase. In estimated data of national survey, it slightly increased from 1975-79 to 1980-84, and remained stable thereafter. The annual number of deaths and age-adjusted death rates tended to decrease from around 1980. The peak of age-specific death rates was seen in infants, age 20 to 40 and old age. The decrease in the age-specific death rate was prominent for age under 20 and old age, but not significant for age 25 to 34. Prefectures in which SMR was high (> or = 120) were distributed all over Japan, but prefectures in which SMR was low (< or = 80) were concentrated in western Japan. The annual number of deaths and age-adjusted death rates began to decrease from around 1980, which coincided with the time the clinical trial of cis-platinum began. More than 100 deaths of testicular cancer are reported even now, early diagnosis, early treatment, and improvement of treatment strategy to far-advanced cases are necessary.