Multiple primary cancers in 5,456 autopsy cases in the National Cancer Center of Japan.

Multiple primary malignant neoplasms in 5,456 consecutive autopsy cases from 1962 to 1981 in the National Cancer Center were analyzed. There were 285 (5.2%) double primary cancers, 58 (1.1%) triple or more, and 65 (1.2%) minute cancers of the thyroid or prostate gland. Higher incidence of second cancer is observed in cancers of the oropharynx, intestine, larynx, uterus, bladder, and thyroid. Organ association between the two cancers was present in certain organs; for example, there was a tendency for upper gastrointestinal tract cancers to be associated with lower gastrointestinal tract cancers. Influence of histologic subtypes in multiple cancer cases is discussed for lung cancer.