Multiple primary cancers in autopsy cases of Tokyo University Hospital (1883-1982) and in Japan Autopsy Annuals (1974-1982).

Multiple primary cancers in 30,386 consecutive autopsy cases from 1883 to 1982 in Tokyo University Hospital and 273,796 registered autopsy cases from 1974 to 1982 in Japan were examined. The frequency of multiple primary cancers among all cancers at Tokyo University Hospital was less than 0.5% until 1940. From 1960, it gradually increased, reaching 6.9% (1970-1982). The average age of patients with a single cancer was around 45 years until 1960. Thereafter, it became high, averaging 54.2 years in 1970-1982. The average age of patients with two and three or more primaries in 1970-1982 was 62.1 and 68.5, respectively. As the autopsy rate of cancers in Japan is 11.1% in 1974-1982, the statistics from the Autopsy Registry are highly representative of those in Japan. The frequency of multiple primaries was 5.5% in the Registry and increased year by year (3.6% in 1974 to 7.1% in 1982). The average age of patients with one, two and three or more primaries was 58.9, 66.7 and 69.8. In these two series, the older the patients, the larger was the number of primaries. In multiple cancers, the frequent combination consisted of the stomach, lung, colon, liver, prostate and thyroid. The stomach, lung, colon and liver were frequent primary sites when they occurred singly. The thyroid and prostate were frequent primary sites found at autopsy. Senescence of the Japanese population is suggested as one of the factors for an increase of multiple primaries in the last 20 years.