Study finds racial, ethnic and socioeconomic disparities in cancer incidence

Feb 3 2010

A New Jersey study found that African-Americans with cancer are less likely to survive it than whites, and residents of poor neighborhoods less likely to survive than are those in wealthier areas of the state.

The racial disadvantage diminishes when socioeconomic status is a consideration, but does not disappear, according to the study in the February issue of the Journal of Health Care for the Poor and Underserved.

"Our results are not surprising," said Xiaoling Niu, a biostatistician at Cancer Epidemiology Services in the New Jersey Department of Health and Senior Services, and lead study author. "Other studies have also revealed poorer survival rates among blacks." Few, however, relied on such a wealth of data on such a diverse population, she said.

The data come from the New Jersey State Cancer Registry, which records nearly all cases among the 8.6 million residents of the state. The authors looked at cases diagnosed from 1986 to 1999 and analyzed survival rates for breast cancer in women; prostate, colorectal and lung cancer; and all cancers combined.

Having cancer and being black or living in a poorer neighborhood meant higher risk of death, even when researchers adjusted for age and cancer stage at diagnosis. "Disparities occur amid relative poverty as well as absolute poverty," the authors wrote.

Other minorities fared better than African-Americans: Cancer survival among Hispanics was the same as for whites; among Asians and Pacific Islanders, it was better.

Taken alone, these data cannot explain the observed racial, ethnic and socioeconomic disparities, but "this kind of study can provide background information for more targeted research into underlying behavioral and social factors," Niu said.

Study co-author Karen Pawlish, an epidemiologist, said, "diet, obesity, physical activity and smoking may affect survival. Biological factors could explain part of the difference, but there may be other factors related to access and quality of care."

Brian Smedley, vice president and director of the Health Policy Institute at the Joint Center for Political and Economic Studies in Washington, said that "separate but unequal" health care services probably are involved.

"We know that minorities are disproportionately clustered in medically underserved communities, where many health care institutions have fewer resources to provide high-quality care," Smedley said. "Research increasingly points to differences in care that patients of color receive compared to whites. Some have called this 'medical apartheid.'"

The N.J. study "raises more questions than it answers," Smedley said. "I'd like to see research move away from describing the problem to looking at interventions that level the playing field."