Multiple primary cancers: review of clinical studies from two Missouri hospitals.

A composite review of a series of hospital-based, clinical studies on the prevalence of simultaneous and nonsimultaneous multiple primary cancers, including those in which data were recorded by the life table method for six different series of cancer patients and one "control" series of patients who did not have cancer at first contact is provided. The studies came from Barnes Hospital and the Ellis Fischel State Cancer Hospital (EFSCH) and span the period from 1914 through 1964. The conclusions of the studies support the concept that the presence of one primary cancer neither increases nor decreases the chances for developing additional cancers with the possible exception of a few "target organ" areas. One study of this period showed a nonrandom distribution of patients with multiple primary cancers referred to EFSCH and this observation merits further epidemiologic research.