Abstract 1773: Racial/ethnic disparities in ovarian cancer treatment and survival
Authors: Bandera Elisa V. , Lee Valerie S. , Rodriguez-Rodriguez Lorna , Powell Bethan , Kushi Lawrence H. 
Published: July 2016

Among ovarian cancer (OC) patients, African American (AA) women are less likely to receive adequate treatment and experience worse survival compared to white women. These differences have been attributed to unequal access to care. AA women are also more likely to be obese with related comorbidities, which are known to affect chemotherapy dosing, and dose reduction has been shown to reduce OC survival. Previous studies have not taken these factors into account and possible disparities among other racial/ethnic groups have received little attention. We evaluated racial/ethnicity differences in chemotherapy dosing and survival in a cohort study of epithelial invasive OC cases who were diagnosed and treated as members of Kaiser Permanente Northern California, and thus had equal access to health care.

Analyses included cases (n = 806) diagnosed from January 2000 to March 2013 receiving adjuvant first-line therapy of carboplatin and paclitaxel with curative intent. Outcomes were overall and OC-specific deaths, with median follow-up of 50 months. Relative dose intensity (RDI) was computed for carboplatin and paclitaxel separately as actual dose administered per week divided by expected dose per week, and average RDI (ARDI) was then calculated for the regimen. Early discontinuation was defined as completing less than four scheduled treatments. Treatment delay was defined as delays in scheduled chemotherapy of more than 7 days. Proportional hazards regression was used to calculate HR and 95% CI after adjusting for relevant covariates.

AA women were more likely to be diagnosed with advanced disease (26.2%), to have hypertension (73.9%) and renal disease (50%), not to have surgery, and to have elevated post-treatment CA-125, as marker of residual disease. Both AA and Hispanic women had high prevalence of obesity, with Hispanic women having the highest prevalence of diabetes (33%). Compared to whites, AAs were more likely to have dose reduction (ARDI&lt;85%), treatment delay, and early discontinuation, while Hispanics were also more likely to have dose reduction, but less likely to have early discontinuation or dose delay. After controlling for age at diagnosis, stage, grade, histology, chemotherapy-related toxic effects, G-CSF use, BMI at diagnosis, comorbidities likely to affect dosing (diabetes, hypertension, cardiovascular diseases, renal disease), ARDI, surgery type, and post-treatment CA 125, AA women had the worst survival. Compared to whites, adjusted HRs (95%CI) for overall mortality were 1.59 (1.03-2.44) for AA; 0.89 (0.61-1.30) for Asians; and 1.31 (0.90-1.91) for Hispanics. Findings for OC-specific mortality were similar.

Our study shows that disparities in OC treatment and survival in AA persisted in a setting of equal access to care and after taking into account treatment and other clinical characteristics and warrants further evaluation of biological, personal, and social factors that may be responsible for these differences.

Citation Format: Elisa V. Bandera, Valerie S. Lee, Lorna Rodriguez-Rodriguez, Bethan Powell, Lawrence H. Kushi. Racial/ethnic disparities in ovarian cancer treatment and survival. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1773.