Race May Affect Early-Onset Lung Cancer

Malignancy under age 50 twice as common in blacks vs. whites, study found

TUESDAY, June 21, 2005 (HealthDay News) -- Blacks from families with a history of lung cancer before the age of 50 face twice the risk of developing the disease than do whites with the same family history.

That's the conclusion of a study appearing in the June 22/29 issue of the Journal of the American Medical Association.

"The risk is greater in black families with early-onset lung cancer compared to whites," said the study's lead author, Michele Cot, an assistant professor of internal medicine at the Karmanos Cancer Institute at Wayne State University in Detroit, Mich.

Cot said she's not sure why the difference exists, but suggests that it could be traced to either a genetic susceptibility or environmental factors.

What the researchers do know is that smoking increases the risk even further.

"Regardless of family history, smoking is still the greatest risk factor for lung cancer. The risk is greatest for people who smoke and who have a family history of early-onset lung cancer," said Cot.

"The message is still very clear: Don't smoke. It's a killer," said Tom Glynn, director of cancer science and trends at the American Cancer Society.

Almost 90 percent of all lung cancers are caused by smoking, according to the American Lung Association. This year, more than 170,000 people will be diagnosed with the disease and about 163,000 people will die from lung cancer. Lung malignancy is the leading cancer killer, according to the American Lung Association.

For this study, the researchers compared 692 people with early-onset cancer and their immediate family members (almost 3,700 people) to 773 unaffected controls and their family members (more than 3,900 people). The analysis included siblings and parents.

Slightly more than one-third of the study population was black. In the early-onset group, 63.9 percent reported past or current use of cigarettes, while 53 percent of the control group reported ever smoking.

The researchers found that as they age, smokers with a family history of early-onset lung cancer face a higher risk of lung cancer than smokers without a family history. And, that increased risk is even higher for blacks (25.1 percent) than for whites (17.1 percent).

After controlling the data for age, sex, smoking history and for chronic lung diseases, the researchers found that blacks with a family history of early-onset lung cancer had more than double the risk of developing the disease than whites with a similar family history.

Glynn said the findings from this study will help give other researchers direction about where to start looking for differences in lung cancer. He believes there's a genetic component, pointing to other research that has suggested that blacks metabolize nicotine more slowly than whites. That means means carcinogens may linger in the body longer. Also, Glynn speculated that differences in smoking patterns may account for some of these differences, including the type of cigarette smoked.

Cot and Glynn agreed that one clear message from this study is the importance of informing physicians of a family history of lung cancer, especially if cancer developed before the age of 50.

More information

To learn more about lung cancer risk factors, go to the National Cancer Institute.

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