Cervical and corpus cancer survival disparities by socioeconomic status in a metropolitan area of Japan

Abstract

The purpose of this study was to analyze socioeconomic differences in cervical and corpus cancer survival, and to investigate if the differences are due to differences in age, cancer stage, histology and treatment. A total of 14,055 cases with cervical cancer and 3,113 cases with corpus cancer were obtained from the Osaka Cancer Registry. Municipality-based SES measurements were obtained from the System of Social and Demographic Statistics. Survival analysis was carried out with Kaplan-Meier survival curves. Three types of Cox proportional hazards regression models were tested to assess survival differences among groups and effects of SES on survival, controlling for clinical factors. SES was related to age and cancer stage for cervical and corpus cancer patients, and histology for cervical cancer patients. Differences were observed in cumulative 5-year survival for cervical cancer patients among low, middle and high unemployment municipalities (68.9%, 64.3% and 50.9%, respectively, P<0.0001). Differences in cumulative 5-year survival for cervical cancer patients were also observed among high, middle and low education municipalities (65.1%, 62.2% and 56.1%, respectively, P<0.0001). Similar patterns in 5-year survival were also found for corpus cancer patients. After adjusting for age, cancer stage, histology and treatment, survival differences between patients from high and low SES areas still remained. In conclusion, our population-based analysis of a metropolitan representative sample in Japan has demonstrated, for the first time in Japan, SES differences in survival following cervical and corpus cancer.