Lung cancer risk prediction models are enhanced by taking into account risk factors by race and by measuring DNA repair capacity, according to research teams led by epidemiologists at the University of Texas M.D. Anderson Cancer Center, Houston, in two complementary papers.

In the first

study to focus on African-Americans, researchers found unique results based on increased exposure to certain risks. Based upon these findings, a specific model was developed to refine further the predictability of lung cancer in this population, according to lead author Carol Etzel, assistant professor in the Department of Epidemiology.

"African-Americans have similar risk factors for lung cancer as Caucasians, but the risk tends to be higher, and there is a stronger association with occupational exposures, such as wood dust and asbestos, than we have previously observed for whites," explains Etzel. "Additionally, we determined the risks associated with chronic obstructive pulmonary disease are substantially higher than those noted in Caucasian subjects." COPDs, such as emphysema, raise a person's risk for lung cancer.

More than 85% of all lung cancers occur in current or former smokers and are the cause of more deaths than any other cancer, killing more than 160,000 Americans annually and millions more worldwide. According to the American Cancer Society, Atlanta, Ga., the incidence of lung cancer is close to 40% higher in African-American men, the death rate approximately 30% higher, and the five-year survival rate is 12% versus 15% for whites.

"The challenge for us is to try to predict which of the United States' estimated 45,000,000 current smokers and 46,000,000 former smokers are at highest risk for developing lung cancer. Accurate prediction models may identify subgroups of these smokers who will benefit most from intensive screening programs and behavioral interventions," says Margaret Spitz, senior author and professor in the Department of EpidemiologY.

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The previously published Spitz lung cancer risk prediction model was based solely on lung cancer cases and controls among Caucasian subjects. Internal and external validation results showed the predictive power of the new African-American group-specific model to approach 79%, versus 66% for the original model. "The predictive abilities are much improved with the new model and underscore the need for further race-specific modeling," maintains Spitz.