June 21, 2005 -- Men and women with a black brother, sister, child, or parent who had lung cancer before age 50 may have a higher risk of lung cancer.
That's also true for families with a white relative who had lung cancer at an early age. But the risk is twice as high for relatives of black patients, says a study in The Journal of the American Medical Association.
"First-degree relatives of black individuals with early onset lung cancer have greater risk of lung cancer than their white counterparts, and these risks are further amplified by cigarette smoking," write researchers.
Study: Consider Family History
If someone in the family had lung cancer before age 50, that should be considered a lung cancer risk factor in their children, parents, or siblings who are at least 18 years old, notes Coté's study.
If doctors know about risk factors beyond tobacco use in their young adult patients, they may be more likely to consider lung cancer in those people. Earlier diagnosis and treatment could make a big difference in the disease's outcome, write researchers.
When Lung Cancer Strikes
"Cigarette smoking has long been established as the major risk factor for lung cancer in the general population," write the researchers. However, lung cancer risk can also run in some families beyond smoking. The greatest risk is in families in which lung cancer strikes before 50, say Coté and colleagues.
In 2004, there were 173,770 new cases of lung cancer in the U.S. Few cases -- 6.7% -- were diagnosed before age 50, says the study.
Lung Cancer Study
Coté's study included more than 7,500 relatives of 692 people with early onset lung cancer and 773 healthy people. All were at least 18 years old and lived in the Detroit area. A third of the group was black.
The data showed a higher lung cancer risk for aging smokers with a brother, sister, or parent who had had lung cancer before 50 compared with those who have relatives whose lung cancer occurred at an older age.
The risk rose when the affected relative was black. By age 70, lung cancer risk was 25% higher for those with an affected black relative, compared with 17% higher for whites.
Relatives of black patients were twice as likely to get lung cancer as relatives of whites. That takes age, sex, pack-years of smoking, pneumonia, and chronic obstructive lung disease into consideration.
Why the Difference?
The reasons for the black-white gap aren't settled in this study. The researchers say genetics may play a role, but that's not certain and other factors could also be involved.
"Our findings demonstrate that lung cancer risk associated with family history of lung cancer is stronger in blacks than in whites," say the researchers. They note that previous studies had similar results, though theirs is the first to report risks for black families.
Ongoing trials should be done to test screening methods for people with a family history of early onset lung cancer, say Coté and colleagues.