Disparities in ovarian cancer care are emblematic of the double standard of care still present in the United States affecting racial/ethnic minorities and disadvantaged populations. Recent data suggest that geographic location contributes to inequalities in access to appropriate care, which leads to worse survival outcomes in populations with more limited access to care. The literature examining geography as a contributing factor to disparities in ovarian cancer treatment and survival is limited in both breadth and depth. Hypothesis: Racial/ethnic and socioeconomic status (SES) disparities in ovarian cancer survival largely reflect disproportionate access to and receipt of high quality care that are associated with geographic location as well as other patient-related and health care system factors. Approach: The current proposal applies established methodologies (spatial and spatiotemporal analyses) in a novel approach to a series of retrospective population-based cohort studies of invasive epithelial ovarian cancer. The spatial analysis will employ the framework of generalized additive models (GAMs) in logistic regression and Cox proportional hazard models, with simultaneous smoothing and adjustment for confounders, to study the impact of geographic location on racial/ethnic and SES disparities in adherence to National Comprehensive Cancer Network (NCCN) ovarian cancer treatment guidelines (Aim 1) and disease-specific survival (Aim 2) in an estimated 29,970 cases reported to the California Cancer Registry (CCR) between 1996- 2013. The temporal and spatiotemporal analyses (Aim 3) will the expand the GAM models to include a trivariate smooth of longitude, latitude, and time to study trends in racial/ethnic and SES disparities in treatment and survival among an estimated 34,965 cases reported to the CCR between 1996-2016. The impact of the introduction of the Affordable Care Act legislation in 2014 on adherence to NCCN treatment guidelines and survival among vulnerable populations will be investigated and compared to temporal trajectories in access to care and survival for the preceding time period. The current proposal also will develop a novel metric (the Observed-to-Expected adherence to treatment guidelines ratio) that combines both structural (case volume) and process (rate of guideline adherence) measures of ovarian cancer care quality that will be integrated as a predictor variable into the analyses of geographic barriers to appropriate care, racial and SES disparities in geographic barriers, geographic predictors of ovarian cancer survival, and temporal/spatiotemporal trends analyses of adherence to treatment guidelines and survival. Expected Outcomes: Collectively, Aims 1, 2 and 3 will provide the necessary framework for intervention strategies targeting underserved populations disproportionately affected by geographic risk factors for inferior ovarian cancer survival. Furthermore, these data will serve as a platform for partnership with the California Department of Health, Office of Health Equity to develop a centralization of ovarian cancer care paradigm that will define quality metrics and criteria for regional referral centers, address disparities in access to appropriate care resulting from geographic location, and be implemented and studied prospectively through collaboration with third party payers.
Disparities in cancer care and outcomes have been linked to race and ethnic classification, socioeconomic status (SES), educational level, geographic locale, culture, and health system factors. This project will provide a more complete understanding of the geographic barriers precluding specific subgroups of women with ovarian cancer from obtaining equivalent access to the necessary care to ensure the best possible outcome, which is of significant public health relevance. By defining the contribution of geographic location to racial/ethnic and socioeconomic disparities in ovarian cancer treatment and survival, our research will provide a template for moving our health care delivery system closer to ensuring the availability of high quality service for all women with ovarian cancer.
