Cancer is the second leading cause of death in the U.S., thus it is crucial to understand as much as possible about the factors affecting cancer rates and mortality. Research has found that rates of cancer diagnosis and mortality vary between rural and urban areas, though the exact nature of geography’s effects on cancer mortality is still incomplete.
In a new policy brief from the Health Resources & Services Administration (HRSA)-funded Southwest Rural Health Research Center at the Texas A&M School of Public Health, researchers led by Dr. Timothy Callaghan, assistant professor in the health policy and management department, build on prior work to study differences in mortality from common cancers – breast, lung, cervical, prostate and colon – across levels of rurality in the U.S..
To accomplish this, Dr. Callaghan along with School of Public Health colleagues Dr. Alva O. Ferdinand, Ms. Marvellous Akinlotan, Ms. Kristi Primm, Dr. Samuel Towne, and Dr. Jane Bolin, analyzed data on cancer mortality from 1999 to 2016 from the National Center for Health Statistics at the Centers for Disease Control and Prevention (CDC). This data included information on cause of death as well as demographic and geographic factors, such as rural or urban status.
Their analysis found a striking difference in cancer mortality across levels of rurality and cancer type. When analyzing lung cancer, prostate cancer, and colon cancer, they found higher mortality rates in rural areas than in urban areas. Discrepancies between rural and urban areas were particularly large for lung cancer. When analyzing breast cancer and cervical cancer on the other hand, mortality rates were higher in large central metro (urban) areas than in rural areas in the U.S.
Dr. Callaghan and colleagues also investigated regional differences in cancer mortality across levels of rurality. Previous studies have found regional variation in how rurality affects other health outcomes, such as diabetes, but little research has focused on cancer mortality. The research team found that for most analyzed cancer types, mortality rates are highest in the South and lowest in the West, with the highest mortality rates typically seen in the rural South. For example, the South had the largest gap between urban and rural lung cancer mortality, with 16.2 more age-adjusted deaths per 100,000 population in rural areas than urban ones. In contrast, the West had a 3.7 point per 100,000 individuals gap for lung cancer mortality between the most urban and most rural areas.
These findings show that rurality’s influence on cancer mortality varies between different types of cancer, highlighting the importance of considering location when studying cancer mortality. However, rurality is not sufficient on its own when trying to understand the influence of geography on differences in cancer mortality. Scholars and policymakers must also consider regional differences in mortality across cancer types. The researchers have noted that further work is needed to explore the reasons behind these variations, with a specific focus on why mortality is higher in rural areas for some cancers but lower for others. Information from such studies could identify changes that could improve outcomes in both rural and urban areas.
Critically, the research presented in this policy brief could help inform health care policy, but the researchers caution that statistical significance tests were not possible with the data they used. This means that the small differences found in their results should be carefully interpreted. Additionally, this analysis did not include other factors that could affect cancer mortality, such as screening rates, smoking status and race and ethnicity, so future studies should also include such characteristics. These limitations notwithstanding, the research provides vital information about cancer mortality in America.