Never Smoked? Genes Still Create Lung Cancer Risk

Updated 9:31 AM EST, Sat, Nov 1, 2008

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Even if you have never smoked, you may still be at risk of developing lung cancer if your parents or siblings have had the disease.

Lung cancer is the leading cause of cancer deaths in both men and women worldwide. About 87 percent of lung cancers are due to tobacco products, either through direct smoking or passive exposure to smoking, according to the American Cancer Society (ACS). More than 213,000 are expected to die of lung cancer in 2007 and 160,000 new cases will be diagnosed this year, according to the ACS.

Researchers at the University of Texas studied a group of 316 people who had lung cancer but never smoked. They also studied 2,465 parents, siblings and children of those cancer patients and 318 people without lung cancer who had never smoked and 2,441 of their close blood relatives.

They found that first-degree relatives of the lung cancer patients were 25 percent more likely to develop any type of cancer than first-degree relatives of the non-cancer group. Children of the cancer patients were twice as likely to develop cancer as children of non-cancer study participants.

Relatives who smoked had a four in 10 chance of developing any type of cancer and were more than five times more likely to develop lung cancer at a young age. Female relatives of the cancer patients had a 58 percent increased risk of breast cancer and mothers of the cancer patients had more than twice the risk of developing breast cancer as mothers of people without cancer. The study also found an increased risk of testicular cancer in male relatives.

"Our analysis provides further evidence for the importance of genetic factors for lung cancer in never smokers," the researchers concluded. They suggested that people with relatives who have been diagnosed with lung cancer may want to consult a physician about their potential risks of developing the disease.

The study was published online in the January 4 issue of the International Journal of Cancer.