1 in 5 women with lung cancer never smoked
July 19, 2007
Up to 20 percent of women who develop lung cancer have never smoked, U.S. researchers found in a study that suggests secondhand smoke may be to blame.
A survey of a million people in the United States and Sweden shows that just 8 percent of men who get lung cancer are nonsmokers.
I have a lot of patients who have never smoked, said Dr. Heather Wakelee of Stanford University in California, who led the
study.
And because of the stigma, people are embarrassed to speak out about their disease. They feel like as soon as they say they have lung cancer, everyone judges them.
She said it is not clear why women may be more likely to get lung cancer even if they have never smoked.
There is a lot of controversy over whether women are more susceptible to smoking at all, whether direct or secondhand smoke, Wakelee said in a telephone interview.
More women exposed to secondhand smoke Writing in Fridays issue of the Journal of Clinical Oncology, Wakelee and epidemiologist Ellen Chang said they tracked the incidence of lung cancer in more than 1 million people aged 40 to 79. All had taken part in various studies of diet, lifestyle and disease, some going back into the early 1970s.
Some groups were mostly white women, such as an ongoing nurses study, while others included ethnically diverse groups, Wakelee said.
Among women who never smoked, the lung cancer incidence rate ranged from 14.4 per 100,000 women per year to 20.8 cases per
100,000. In men, it ranged from 4.8 to 13.7 per 100,000. Rates were about 10 to 30 times higher in smokers.
This would translate to about 20 percent of female lung cancer patients having been nonsmokers and 8 percent of males, they said. That compares with American Cancer Society estimates of about 10 percent to 15 percent for all lung cancer patients.
That estimate has been thrown about without any hard data to support it. This data sort of supports it, Wakelee said.
Chang said that because more men smoke than women, women may be more likely to be exposed to secondhand smoke, even when they are classified as never-smokers.
We know that secondhand smoke does increase the risk of lung cancer so its likely that a lot of these cases we observe are attributable to that, she said in a statement.