Geographic pathology of uterine cancers in Oregon: risks of double primaries and effects of socioeconomic status.

An intensive statewide study of uterine cancer incidence for the period 1968-1972 revealed that women with one histologic type of uterine cancer were much more susceptible to the simultaneous presence of a second histologic type than were the rest of the residents of the state. Squamous cell carcinoma was the most common uterine cancer; peak number and rate were found in the age group 25-29 years, indicating the need for periodic screening of young adult women and the need for discussion of neoplasia risk in adolescent sex education classes. Risks of squamous cell carcinoma and leiomyosarcoma were excessive among blacks. Socioeconomic status had a strong and consistent inverse relationship with uterine squamous cell carcinoma incidence, implying that its major risk determinant, sexual behavior, could have a similar socioeconomic pattern. Uterine adenocarcinoma incidence had a weaker but consistent direct relationship with socioeconomic status for which the cause is unknown.