The effect of time on racial differences in epithelial ovarian cancer (OVCA) diagnosis stage, overall and by histologic subtypes: a study of the National Cancer Database.

Purpose: Previous studies assessing racial and ethnic differences in ovarian cancer (OVCA) diagnosis stage fail to present subtype-specific results and provide historic data on cases diagnosed between 10 and 20 years ago. The purpose of this analysis is to assess non-Hispanic Black (NHB) and non-Hispanic White (NHW) differences in late-stage diagnosis including; (1) factors associated with late-stage diagnosis of invasive epithelial OVCA overall and by histologic subtypes, (2) potential changes across time and (3) current patterns of trends in a national cancer registry in the USA and Puerto Rico between 1998 and 2011.

Methods: NHB and NHW OVCA cases were derived from the National Cancer Database (NCDB). Diagnosis stage was analyzed as a dichotomous and a four level-category variable, respectively; early (stages I and II; localized) versus late (stages III and IV; regional and distant) and stages I, II, III and IV. Diagnosis period was trichotomized (1998-2002, 2003-2007, 2008-2011). Racial differences in stage were tested using Chi-square statistics. Odds ratios (OR) and 95 % confidence intervals (95 % CI) were estimated using multivariable binomial and generalized ordered logistic regressions. Interactions between race and diagnosis period were evaluated.

Results: Between 1998 and 2011, 11,562 (7.8 %) NHB and 137,106 (92.2 %) NHW were diagnosed with OVCA. In adjusted models, NHB were significantly more likely diagnosed with late-stage OVCA than NHW (ORadj 1.26, 95 % CI 1.19-1.33). Interaction between race and diagnosis period was marginally significant (p value = 0.09), with racial differences in stage decreasing over time (1998-2002: ORadj 1.36, 95 % CI 1.23-1.49; 2003-2007: ORadj 1.27, 95 % CI 1.15-1.39; 2008-2011; ORadj 1.15, 95 % CI 1.05-1.27). NHB were also more likely to be diagnosed with stage 4 high-grade serous (ORadj 1.46, 95 % CI 1.22-1.74), clear cell (ORadj 2.71, 95 % CI 1.94-3.79) and mucinous (ORadj 2.78, 95 % CI 2.24-3.46) carcinomas than NHW.

Conclusions: Racial differences in late-stage OVCA diagnosis exist; however, these differences are decreasing with time. Within NCDB, NHB are significantly more likely diagnosed with late-stage OVCA and more specifically high-grade serous, clear cell and mucinous carcinomas than NHW.