In order to address disparities, say the authors, it will be key to maintain policies associated with better outcomes for low-income communities, such as the expansion of Medicaid, that could provide access to affordable cancer care.
While advances in the prevention, diagnosis, and treatment of cancer have led to meaningful reductions in cancer death rates in the United States, substantial disparities remain among different geographic and socioeconomic patient populations.
A newly published investigation appearing in JAMA sought to assess cancer mortality at the US county level, both to study the association between county income levels and cancer death rates and to identify factors that may serve as mediators of disparity.The cross-sectional study included all 3135 US counties that had cancer death rate data available from 2014 in the Institute for Health Metrics and Evaluation database. The investigators then linked cancer death rates with the median household income for each county. They then stratified the counties as high-, medium-, or low-income.
Across the counties, median incomes ranged from $22,126 to $121,250 per year. The highest-income counties had a median income of $55,780, and the lowest-income group had a median income of $33,445. Low-income counties had higher proportions of black residents, rural residents, and reported poor or fair health.
Cancer death rates varied significantly across the 3 income levels, with a mean (SD) rate of 229.7 (32.9) deaths per 100,000 person-years in low-income counties versus 204.9 (26.3) deaths per 100,000 person-years in medium-income counties and 185.9 (24.4) deaths per 100,000 person-years in high-income counties.
Geographic clusters with the highest death rates were found in the Mississippi River Delta and in Appalachia, and many of these “hot spots” were in low-income counties.
The researchers identified 8 factors that they say may mediate county-level socioeconomic cancer disparities. Three factors were health risk behaviors (obesity, smoking, and physical inactivity), 2 were clinical care factors (unaffordable care and low-quality care), 2 were health policies (smoke-free laws and the state Medicaid fee index), and 1 was a health environment factor (food insecurity).
“In aggregate, these factors explained more than four-fifths (81.25%) of the association between county-level median incomes and cancer death rates,” wrote the authors.
Taken separately, the factors most likely to be linked with cancer death rates were food insecurity and low-quality care. In terms of the disparity risk index—a composite measure of the factors that may mediate the association between county levels of income and cancer death rates—there were clear differences among mean (SD) low-income (0.64 [0.57]), medium-income (0.03 [0.48]), and high-income (−0.58 [0.50]) counties, with higher scores indicating higher concentrations of the potential mediators.
In order to address disparities, say the authors, it will be key to maintain policies associated with better outcomes for low-income communities, such as the expansion of Medicaid, that could provide access to affordable cancer care. Furthermore, the disproportionate number of black Americans in low-income counties with high cancer death rates “highlights the need to dismantle structural racism, which contributes to inequalities in social and economic power and to the segregation of black Americans into area hot spots of counties having disproportionately more cancer deaths,” wrote the authors.
In a response to the study, Monica M. Bertagnolli, MD, president of the American Society of Clinical Oncology (ASCO), said in a statement, "This study reinforces the unfortunate reality that too many Americans can’t access quality cancer care despite the progress we have made in understanding and treating the disease. All patients deserve access to high quality care, but where they live often dictates their chances of surviving cancer. Simply put, this is unacceptable.”
Bertagnolli added that ASCO joins the study’s authors in calling for public health programs to target lower-income counties in order to reduce disparities, and said that policy makers, providers, and researchers all have a responsibility to examine and eliminate obstacles to cancer care.
O’Connor JM, Sedghi T, Dhodapkar M, Kane MJ. Factors associated with cancer disparities among low-, medium- and high-income US communities. JAMA Network Open. 2018;1(6):e183146. doi: 10.1001/jamanetworkopen.2018.3146.