SOCIAL-CLASS AND CANCER-PATIENT SURVIVAL IN FINLAND

The effect of social class on survival was assessed in a cohort of can cer patients identified from the nationwide population-based Finnish C ancer Registry. The cohort consisted of all reported cases of the 12 m ost common types of cancer occurring in Finland between 1971 and 1985 among persons born in 1906-1945 (n = 106,661). Social class informatio n based on occupation was obtained individually for each patient from the population census of 1970. Both observed and corrected (i.e., caus e of death-specific) 5-year survival rates were used in the analyses. A statistically significant linear effect of social class on age-adjus ted relative risk of cancer death was observed in six of 12 cancer typ es among men and in nine of 12 among women; and the risk was highest f or those in the lowest social class. The relative risk of death due to cancer for social class I (highest) relative to social class IV (lowe st) was lowest in bladder cancer (relative risk (RR) = 0.46, 95% confi dence interval (CI) 0.34-0.61) and kidney cancer (RR = 0.61, 95% CI 0. 48-0.78) among men and in corpus uteri (RR = 0.51, 95% CI 0.36-0.72) a nd rectum cancer (RR = 0.56, 95% CI 0.42-0.74) among women. The differ ences between results obtained using corrected and observed survival r ates were small. These findings indicate that social class is an impor tant determinant of cancer patient survival. Additional research is re quired to clarify the etiology of the social class differences and to identify factors that could be used for developing strategies to dimin ish such inequalities.