Survival Disparity in Black & White Women with Ovarian Cancer: The Role of Mediators & Contextual Factors
thesisposted on 13.12.2012 by Caryn E. Peterson
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Ovarian cancer remains one of the most lethal of all cancers. While the incidence of ovarian cancer is higher among White women, survival is significantly poorer among Black women. Yet the reasons for this disparity are not well-understood. This project evaluated predictors of late-stage diagnosis to determine if there were significant racial differences in these predictors that might explain the disparity in survival. In addition, this project examined whether factors related to socioeconomic environment, tumor characteristics, and risk factors associated with longer lifetime ovulation and higher gonadotropin levels are mediators of the racial disparity in ovarian cancer survival. Data were obtained from women diagnosed with ovarian cancer in Cook County, Illinois. Socioeconomic environment was assessed using two well-established measures: concentrated disadvantage and concentrated affluence. Tumor characteristics included tumor grade, histologic sub-type, and residual lesion status. Hormonal and reproductive risk factors included length of ovulatory period and HRT history.The proportion of the survival disparity explained by these factors was estimated by rescaling coefficients from logistic regression using the method of Karlson, Holm, and Breen (2010). Age at diagnosis, poverty, an index of socioeconomic status, pathologic grade, and histologic sub-type were all significant predictors of late-stage diagnosis. However, race was not a significant predictor of late-stage diagnosis, which suggests that other factors may account for the racial disparity in survival. More Black women than White women survived less than five years following their diagnoses (63% vs. 48%, respectively, p = 0.004). Tumor characteristics explained 37% percent of the racial disparity in five-year survival (p = 0.03). Socioeconomic environment accounted for 35% of the racial disparity in survival (p = 0.39). Risk factors that may be associated with more aggressive tumors accounted for 15% of the disparity in survival (p = 0.13). Together, these factors explained 65% of the survival disparity (p = 0.20). Differences in tumor grade and histology were shown to be important mediators in the relation between race and disparate ovarian cancer survival. Socioeconomic environment and factors associated with longer lifetime ovulation and higher levels of gonadotropins may also explain a portion of this disparity.