Disparity in Breast Cancer Late Stage at Diagnosis in Missouri: Does Rural Versus Urban Residence Matter?

Abstract

Despite the fact that black women have a lower incidence of breast cancer compared to white women, black women experience higher death rates than any other group. We examined the stage of breast cancer presentation by race and geographic region using population-based breast cancer incidence in all 115 counties in the state of Missouri. We used 2003-2008 breast cancer incidence data from Missouri Cancer Registry and Research Center. County of residence was categorized as urban or rural using the rural-urban continuum code. We computed the conditional proportion of stage at diagnosis by race and metropolitan status and also used Pearson's chi-squared test with Yates' continuity correction to determine statistical significance of association. Results of the study indicate that a greater proportion of black women (38.8%) compared to white women (30.2%) were diagnosed with more advanced breast metastasis. Our results further suggest that stage at diagnosis depended on county of residence or metropolitan status (p = .04). Women living in non-metropolitan counties were slightly more likely to have late-stage breast cancer than their metropolitan counterparts (32.0 vs 30.7%). Overall, black women had 1.5-fold increased odds of late-stage breast cancer diagnosis compared to their white counterparts (OR = 1.50; 95% CI, 1.39, 1.63; p < 0.0001). While the odds of late diagnosis among women living in non-metropolitan or rural counties was over 11% higher compared with their metropolitan or urban counterpart. The current study corroborates previous findings that the risk of late-stage breast cancer diagnosis was higher among women residing in non-metropolitan rural counties.