Invasive Cancer Incidence, 2004-2013, and Deaths, 2006-2015, in Nonmetropolitan and Metropolitan Counties - United States

Abstract

Problem/condition: Previous reports have shown that persons living in nonmetropolitan (rural or urban) areas in the United States have higher death rates from all cancers combined than persons living in metropolitan areas. Disparities might vary by cancer type and between occurrence and death from the disease. This report provides a comprehensive assessment of cancer incidence and deaths by cancer type in nonmetropolitan and metropolitan counties.

Reporting period: 2004-2015.

Description of system: Cancer incidence data from CDC's National Program of Cancer Registries and the National Cancer Institute's Surveillance, Epidemiology, and End Results program were used to calculate average annual age-adjusted incidence rates for 2009-2013 and trends in annual age-adjusted incidence rates for 2004-2013. Cancer mortality data from the National Vital Statistics System were used to calculate average annual age-adjusted death rates for 2011-2015 and trends in annual age-adjusted death rates for 2006-2015. For 5-year average annual rates, counties were classified into four categories (nonmetropolitan rural, nonmetropolitan urban, metropolitan with population <1 million, and metropolitan with population ≥1 million). For the trend analysis, which used annual rates, these categories were combined into two categories (nonmetropolitan and metropolitan). Rates by county classification were examined by sex, age, race/ethnicity, U.S. census region, and cancer site. Trends in rates were examined by county classification and cancer site.

Results: During the most recent 5-year period for which data were available, nonmetropolitan rural areas had lower average annual age-adjusted cancer incidence rates for all anatomic cancer sites combined but higher death rates than metropolitan areas. During 2006-2015, the annual age-adjusted death rates for all cancer sites combined decreased at a slower pace in nonmetropolitan areas (-1.0% per year) than in metropolitan areas (-1.6% per year), increasing the differences in these rates. In contrast, annual age-adjusted incidence rates for all cancer sites combined decreased approximately 1% per year during 2004-2013 both in nonmetropolitan and metropolitan counties.

Interpretation: This report provides the first comprehensive description of cancer incidence and mortality in nonmetropolitan and metropolitan counties in the United States. Nonmetropolitan rural counties had higher incidence of and deaths from several cancers related to tobacco use and cancers that can be prevented by screening. Differences between nonmetropolitan and metropolitan counties in cancer incidence might reflect differences in risk factors such as cigarette smoking, obesity, and physical inactivity, whereas differences in cancer death rates might reflect disparities in access to health care and timely diagnosis and treatment.

Public health action: Many cancer cases and deaths could be prevented, and public health programs can use evidence-based strategies from the U.S. Preventive Services Task Force and Advisory Committee for Immunization Practices (ACIP) to support cancer prevention and control. The U.S. Preventive Services Task Force recommends population-based screening for colorectal, female breast, and cervical cancers among adults at average risk for these cancers and for lung cancer among adults at high risk; screening adults for tobacco use and excessive alcohol use, offering counseling and interventions as needed; and using low-dose aspirin to prevent colorectal cancer among adults considered to be at high risk for cardiovascular disease based on specific criteria. ACIP recommends vaccination against cancer-related infectious diseases including human papillomavirus and hepatitis B virus. The Guide to Community Preventive Services describes program and policy interventions proven to increase cancer screening and vaccination rates and to prevent tobacco use, excessive alcohol use, obesity, and physical inactivity.

FIGURE 1

Average annual age-adjusted rates* of new cases^† of common cancers (2009–2013) and deaths^§ from common cancers (2011–2015) in nonmetropolitan and metropolitan counties^¶ — United States * Per 100,000 persons, age-adjusted to the 2000 U.S. standard population. ^† Cancer incidence data compiled from cancer registries that meet the data quality criteria for all invasive cancer sites combined, representing approximately 97% of the U.S. population. (Data from Nevada did not meet U.S. Cancer Statistics publication criteria for 2004–2013, and county-level data were not available for Kansas and Minnesota.) Late-stage cancers include those diagnosed at the regional or distant stage, after the cancer has spread. ^§ Cancer mortality data are from the National Vital Statistics System (representing 100% of the U.S. population). ^¶ Counties were identified using the U.S. Department of Agriculture Economic Research Service 2013 vintage rural-urban continuum code, which categorizes nonmetropolitan counties by degree of urbanization and adjacency to a metropolitan area, and metropolitan counties by the population size of their metropolitan area (https://www.ers.usda.gov/data-products/rural-urban-continuum-codes).

FIGURE 2

Trends* in annual age-adjusted incidence rates^† among persons of all ages for common cancers in nonmetropolitan and metropolitan counties,^§ by year of diagnosis — United States, 2004–2013 Abbreviations: AAPC = average annual percentage change; NS = not significant. * Trends were measured with AAPC in annual rates (per 100,000, age-adjusted to the 2000 U.S. standard population) calculated using joinpoint regression, which allowed different slopes for two periods; the year at which slopes changed could vary by county classification. To determine whether AAPC was significantly different from zero, a t-test was used for 0 joinpoints, and a z-test was used for 1 joinpoint. Rates were considered to increase if AAPC >0 (p<0.05) and to decrease if AAPC <0 (p<0.05); otherwise rates were considered stable. All AAPCs were significantly different (p<0.05) from zero unless otherwise indicated (by NS). ^† Cancer incidence data were compiled from cancer registries that meet the data quality criteria for all invasive cancer sites combined, representing approximately 97% of the U.S. population. (Data from Nevada did not meet U.S. Cancer Statistics publication criteria for 2004–2013, and county-level data were not available for Kansas and Minnesota.) Late-stage cancers include those diagnosed at the regional or distant stage, after the cancer has spread. ^§ Nonmetropolitan and metropolitan counties were identified using the U.S. Department of Agriculture Economic Research Service 2013 vintage rural-urban continuum code (https://www.ers.usda.gov/data-products/rural-urban-continuum-codes). AAPCs differed significantly between nonmetropolitan and metropolitan counties for cancers of the lung and colon and rectum but did not differ for cancers of all sites, female breast, prostate, or cervix.

FIGURE 3

Trends* in annual age-adjusted death rates among persons of all ages for common cancers in nonmetropolitan and metropolitan counties,^† by year of death — United States, 2006–2015 Source: CDC, National Center for Health Statistics. National Vital Statistics System, mortality data. Atlanta, GA: CDC. Abbreviations: AAPC = average annual percentage change; NS = not significant. * Trends were measured with AAPC in annual rates (per 100,000, age-adjusted to the 2000 U.S. standard population) calculated using joinpoint regression, which allowed different slopes for two periods; the year at which slopes changed could vary by county classification. To determine whether AAPC was significantly different from zero, a t-test was used for 0 joinpoints, and a z-test was used for 1 joinpoint. Rates were considered to increase if AAPC >0 (p<0.05) and to decrease if AAPC <0 (p<0.05); otherwise rates were considered stable. All AAPCs were significantly different (p<0.05) from zero unless otherwise indicated (by NS). ^† Nonmetropolitan and metropolitan counties were identified using the U. S. Department of Agriculture Economic Research Service 2013 vintage rural-urban continuum code (https://www.ers.usda.gov/data-products/rural-urban-continuum-codes). AAPCs differed significantly between nonmetropolitan and metropolitan counties for cancers of all sites, the lung, the colon and rectum, and the female breast but did not differ for cancers of the prostate or cervix.