Rural-Urban Disparities in Stage of Diagnosis Among Cancers With Preventive Opportunities.

Introduction: Despite having lower overall incidence rates, rural populations tend to have higher cancer mortality rates. Rural populations often have higher rates of cancers with primary and secondary prevention modalities. However, there is limited research on rural-urban differences in incidence by stage. Therefore, the objective was to assess rural-urban differences in cancer rates by stage.

Methods: The North American Association of Central Cancer Registries public use data set (2009-2013) was used to calculate age-adjusted incidence rates and rate ratios (rural versus urban) for all stageable cancers, tobacco-associated cancers, human papillomavirus-associated cancers, and individual cancers with screening modalities. Analyses were performed in summer 2017 for all populations and stratified by race/ethnicity and region for localized and distant stages.

Results: For all cancers, rural populations had lower rates of localized stage cancers (rate ratio=0.95, 95% CI=0.95, 0.95) and higher rates of distant stage cancer (rate ratio=1.05, 95% CI=1.05, 1.06). Higher rates of distant stage human papillomavirus-associated, tobacco-associated, colorectal, oropharyngeal, lung, cervical cancers, and melanoma were identified in rural populations. Racial/ethnic stratifications identified higher rates of distant stage cancers in rural non-Hispanic whites, but not non-Hispanic blacks and Hispanics. Distant stage lung cancer rates were higher in all rural groups, whereas rural whites had higher distant rates of tobacco-associated, colorectal, and cervical cancers, and rural blacks had higher distant rates for human papillomavirus-associated and oral cancers. Regional stratifications showed the greatest disparity in stage at diagnosis in the South.

Conclusions: These findings might help explain the higher rural cancer mortality rates and provide additional evidence to support targeted interventions.