African-Americans have fewer incidences of thyroid cancer but have a more advanced form of the disease once they receive a diagnosis and are more likely to die from it, according to a study in the spring issue of Ethnicity & Disease.
"We think that the mortality rate is probably due to an access-to-care issue," said lead author Christopher Hollenbeak, PhD, in an interview with Health Behavior News Service, part of the Center for Advancing Health. His study found that African-Americans had a 1% higher mortality rate, though thyroid cancer is twice as common among whites.
"African-Americans were more likely to present with tumors larger than 4 centimeters, which implies that the tumors sat there and grew a lot longer," said Hollenbeak, an associate professor of surgery and health evaluation sciences at Penn State College of Medicine.
The researchers also found African-Americans were more likely to present with anaplastic thyroid cancer, which is a fatal and advanced form of the disease, as opposed to papillary and medullary cancers, which are most common and easily treated.
The researchers analyzed the National Cancer Institute's registry data from 1992 to 2006 that tracked five-year survival rates of thyroid cancer patients. The registry currently represents 17 U.S. states, but reflects national cancer trends, Hollenbeak said. Among nearly 27,000 patients, fewer than 2,000 patients were African-American and the rest were white.
"Part of this reflects the difference in distribution between the races. You just don't see thyroid cancer much among blacks as you do among whites," Hollenbeak said. He added that while the 1% difference might seem insignificant, the study's collective findings -- that African-Americans more often present with an advanced form of the disease -- indicates a disparity in care that should be addressed with policy change.
But Susan Shaw Devesa, PhD, a National Cancer Institute epidemiologist who is not affiliated with the study, views the findings from a different perspective. Comparing data of both racial groups with the same disease classifications, she noted the higher rate of papillary tumors in whites. "The data suggest that there is little racial disparity in survival when tumor type and size are accounted for," she told Health Behavior News Service.
According to the study authors, it's speculated that the cancer is caused by environmental factors such as x-ray exposure. But the authors also said that the uptick in incidences might be due to more effective diagnostics.
