Rural-Urban Differences in Cancer Incidence and Trends in the United States

Abstract

Background: Cancer incidence and mortality rates in the United States are declining, but this decrease may not be observed in rural areas where residents are more likely to live in poverty, smoke, and forego cancer screening. However, there is limited research exploring national rural-urban differences in cancer incidence and trends.Methods: We analyzed data from the North American Association of Central Cancer Registries' public use dataset, which includes population-based cancer incidence data from 46 states. We calculated age-adjusted incidence rates, rate ratios, and annual percentage change (APC) for: all cancers combined, selected individual cancers, and cancers associated with tobacco use and human papillomavirus (HPV). Rural-urban comparisons were made by demographic, geographic, and socioeconomic characteristics for 2009 to 2013. Trends were analyzed for 1995 to 2013.Results: Combined cancers incidence rates were generally higher in urban populations, except for the South, although the urban decline in incidence rate was greater than in rural populations (10.2% vs. 4.8%, respectively). Rural cancer disparities included higher rates of tobacco-associated, HPV-associated, lung and bronchus, cervical, and colorectal cancers across most population groups. Furthermore, HPV-associated cancer incidence rates increased in rural areas (APC = 0.724, P < 0.05), while temporal trends remained stable in urban areas.Conclusions: Cancer rates associated with modifiable risks-tobacco, HPV, and some preventive screening modalities (e.g., colorectal and cervical cancers)-were higher in rural compared with urban populations.Impact: Population-based, clinical, and/or policy strategies and interventions that address these modifiable risk factors could help reduce cancer disparities experienced in rural populations. Cancer Epidemiol Biomarkers Prev; 27(11); 1265-74. ©2017 AACR.

Figure 1

Temporal Trends in Rural and Urban Cancer Incidence, 1995-2013; Rates are per 100,000 and age-adjusted to the 2000 US standard population. “Total” indicates the percent change in incidence between 1995 and 2013, and “APC” indicates the annual percentage change in rates during this interval. ∧ notes an APC that is statistically significantly different than zero (P<0.05). Figure 1 contains multiple panels displaying the trends, total percent change, and annual percentage change (1995-20130 for eight cancer groups: (A): All cancer; (B): Lung cancer; (C): Breast cancer; (D): Colorectal cancer; (E): Cervical cancer; (F):Prostate cancer; (G): HPV-associated cancer; (H): Tobacco-associated cancer.