Social class and colon cancer survival in Finland.

METHODS. Social class differences in colon cancer survival were studied in 3147 patients with colon cancer diagnosed in Finland from 1979-1982. Of these patients, 2969 were eligible for survival analysis. RESULTS. A clear social class gradient in colon cancer survival was detected. The difference in the age-adjusted relative risk of death due to colon cancer between the highest (I) and lowest (IV) social class was 19%. Stage of disease at diagnosis accounted for a substantial proportion of differences in survival, and treatment accounted for the rest of them. Differences in treatment by social class were most apparent among patients with advanced or unknown stage of disease at diagnosis. Controlling for the place of residence had little effect on the survival differences. Delay in diagnosis did not account for the observed differences in survival by social class.