A New Angle on Disparities
Study: Black patients in highly segregated neighborhoods were less likely to have lung cancer surgery.
Despite significant progress in treating and preventing cancer, not all patients have benefited equally. Racial and ethnic minorities, as well as people in medically underserved communities, experience higher rates of some kinds of cancer and are more likely to die of certain types.
Researchers have sought to determine whether cancer disparities stem from biological differences, socioeconomic status, behavioral factors, or a combination of causes.
A study recently published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research (AACR), examined the cancer health disparity issue through a unique lens: segregation.
“Racial residential segregation remains a persistent problem in the United States,” said the study’s lead author, Asal Mohamadi Johnson, PhD, MPH, an assistant professor of integrative health science at Stetson University in DeLand, Florida. “Instead of solely looking at health disparities between white and black patients, our study focused on differences in survival among black patients resulting from different levels of neighborhood segregation.”
Dr. Johnson’s study focused on non-small cell lung cancer (NSCLC), the most common type of lung cancer. If caught at an early stage, the disease can sometimes be successfully treated by surgical resection. Previous research has documented the fact that black patients are less likely to receive NSCLC surgery and more likely to die of the disease.
In this study, Dr. Johnson and colleagues conducted a retrospective cohort study of patients diagnosed with NSCLC between January 2000 and December 2009, using data from the Georgia Comprehensive Cancer Registry. Researchers measured the degree of segregation of the patients’ neighborhoods by isolation index, which measures the probability of living in proximity to individuals from the same racial or ethnic group. The researchers also examined the impact of economic deprivation and educational attainment.
For black patients, the level of segregation of their neighborhoods was the strongest predictor of whether they would receive the surgery. The study showed that compared with patients living in the least-segregated areas, the patients in the most-segregated areas were 65 percent less likely to get the surgery. The patients in the second most-segregated areas were 63 percent less likely to receive the surgery.
For white patients, educational levels in the neighborhood played the largest role in determining their chances of receiving the surgery. The white patients who lived in areas with the lowest levels of education were 48 percent less likely to receive the surgery compared with those living in areas with the most highly educated population. Segregation had no significant effect.
Black patients also had lower five-year survival compared with white patients. However, after controlling for receipt of surgery, the survival disparity between black and white patients disappeared, suggesting this disparity may be largely explained by differences in receipt of surgery.
Black patients living in the neighborhoods with the highest levels of segregation and economic deprivation were 31 percent more likely to die than black patients living in the least segregated and economically deprived areas.
Dr. Johnson said that segregation creates a cycle of economic impoverishment, with poorer education opportunities, fewer prospects for employment, and less access to medical services. All of these factors can exacerbate health disparities, she added. And she advocated urban planning and public policy efforts to encourage a shift to more racially and economically mixed neighborhoods.
“Health disparities are a result of a combination of social, cultural, behavioral, and political factors. Any genuine commitment to address them successfully should include experts on economic development and urban planning, as well as policymakers and the medical community,” she said. “Most importantly, the residents of these communities must be involved and a part of the process.”
Dr. Johnson said a limitation of the study is that researchers did not have data on individual socioeconomic status, comorbidity, and specific causes of death. Also, she said, segregation can be measured in numerous ways, and alternate measures may have resulted in different results.