Having a close relative who has been diagnosed with lung
cancer nearly doubles your risk of developing the deadly disease, the HealthDay
News reported on Thursday.
A new study in the October issue of Chest found
that people with a first-degree relative who had lung cancer had a 95
percent higher risk of developing the disease themselves, according to the
report.
First-degree relative means mother, father or sibling.
"Our long-term follow-up of a large-scale,
population-based cohort identified a significant increase in the risk of lung
cancer associated with a family history of lung cancer in a first-degree
relative in a Japanese population," the study authors wrote.
Dr. Jay Brooks, chairman of hematology and oncology at
the Ochsner Clinic Health System in Baton Rouge, La., said this study confirms
what's already known about family history and the risk of lung cancer, and that
"it's an important thing for physicians to realize."
"As a clinician, when I have someone with lung cancer, I
ask the family members, 'Who smokes cigarettes?' Then I explain that they have a
two- to three-fold higher risk of lung cancer because of their family history,
and this is just another reason to quit smoking because they have a genetic
susceptibility to the carcinogens in tobacco," explained Brooks.
More than 180,000 new cases of lung cancer are diagnosed
each year in the United States, and nearly 170,000 Americans die from the
disease annuall, according to estimates by the US Centers for Disease Control
and Prevention.
The National Institutes of Health said that though not
everyone who gets lung cancer is a smoker or former smoker, cigarette smoking is
absolutely the biggest risk factor for the disease.
The study followed more than
102,000 middle-aged and older Japanese adults for 13 years; there were more women (53,421) than men
(48,834). During the study period, 791 cases of lung cancer were diagnosed.
The researchers found that association of a first-degree
relative with lung cancer and odds of developing the disease was stronger
for women than men. Women who had a first-degree relative
with lung cancer almost had triple the risk of lung cancer, while men with a
first-degree relative with lung cancer had about a 70 percent higher risk.
But Brooks and Dr. Ann G. Schwartz, who wrote an
accompanying editorial in the same issue of the journal, both said it wasn't clear why family history would
confer a greater risk for women than for men. Schwartz said one
possibility is that women are more familiar with their family histories and may
just be reporting family history more accurately. Brooks also pointed out that this
finding might only apply to Japanese women and not other populations.
Moreover, people who had never smoked had a higher risk
of developing lung cancer themselves if they had a first-degree relative with the
disease than did smokers with close family members with lung cancer.
It's also not clear exactly why family history is
associated with a greater risk for those who never smoked, though Schwartz said
it may have something to do with different lung cancer types. It's possible that
the type of lung cancer nonsmokers often get may also be one where
the genetic susceptibility is passed from generation to generation.
Family history was also more strongly associated with a particular type of lung cancer
-- squamous cell carcinoma, the report said.
While there aren't clear-cut screening guidelines in place for someone
with a family history of lung cancer, Schwartz said, "You need to make your
physician aware of your family history; don't discount it."
She added that she'd like to see people with a family history of the
disease identified as high-risk for lung cancer and included in screening
studies.
"If you have a family history of lung cancer, you have a
genetic susceptibility to the carcinogens in directly inhaled and in secondhand
tobacco smoke. Avoid all exposure to tobacco, quit smoking if you're a smoker,"
and don't let your children be exposed to tobacco smoke, Brooks said.
