Socioeconomic status and epithelial ovarian cancer survival in Sweden.

Abstract

To investigate socioeconomic disparities in epithelial ovarian cancer (EOC) survival in Sweden. A cohort of 635 women with invasive EOC who participated in a nationwide population-based case-control study was included in the present population-based prospective study. Women were diagnosed with EOC between 1993 and 1995. Mortality until 31 December 2007 was determined through linkage with the Swedish Cause of Death Registry. Clinical data (tumor stage and tumor differentiation) and indicators of socioeconomic status (SES, education level, and annual individual disposable income) were retrieved from medical records and a nationwide database, respectively. The Cox proportional hazards regression model and the Laplace regression model were used to estimate the effect of clinical factors and SES on EOC survival. The main factors associated with EOC survival were tumor stage and tumor differentiation: women with stage II, III, and IV tumors had a greater mortality risk than those with stage I tumors [hazard ratio (HR) 2.65, 95 % confidence interval (CI) 1.73-4.07; HR 6.69, 95 % CI 4.85-9.22; HR 12.84, 95 % CI 8.90-18.66, respectively]. After adjustment for these tumor characteristics, no clear association remained between our indicators of SES and EOC survival, but better survival was observed among women with stage IV tumors and a higher income level, and among women with poorly differentiated tumors and a higher education level. Nevertheless, there was no evidence of extended survival among women with higher compared to lower SES. Our study provides no convincing evidence of an association between SES and EOC survival in Sweden.