Women who don't smoke still risk lung cancer

A pesky cough, that's all.

The last thing on Michaelle Gall's mind was late-stage lung cancer.

She had just turned 41. She was a physically fit mom and nonsmoker, except for the rare social occasions when some friends might light up.

What created the Lenexa, Kan., woman's tumors is a mystery. It's that way each year for tens of thousands of Americans, mostly women, who defy the conventional profile of a lung cancer patient.

With smoking rates plummeting and U.S. deaths to lung cancer dropping, research shows that roughly one in five women now diagnosed seldom, if ever, put a cigarette to their lips. The same is thought to be true for about one in 10 men.

Only in recent years have scientists begun to explore why.

For Gall, the coughing that arose around Christmas led to a doctor visit in January.

Added Gall, upbeat in manner but still adjusting to the shock: "I say 'survivor' because a nurse told me that now I know I have it, I should consider myself a survivor."

Her treatment is just beginning, and doctors are hopeful she'll benefit from a new drug that targets a genetic abnormality found in Gall and a small percentage of other cancer patients.

The larger question, yet to be answered, is why lung cancer not linked to a history of smoking appears more apt to strike women than men.

The peripheral hazards would seem just as dangerous to men: exposure to radon gas in the basement, or to asbestos, or to secondhand smoke. Genetics and air pollutants can also trigger the disease, as can unventilated cooking oil fumes, which in some parts of the world is related to women's work.

And there's this question: In an age of anti-smoking campaigns proving so successful in cutting lung cancer deaths, how should society deal with the others -- those patients rocked by the news that they have an often deadly condition through no fault of their own?

The group is not tiny. Of the 200,000 or so Americans diagnosed yearly with lung cancer, about 15 percent -- or 30,000 -- are nonsmokers, studies suggest. Even if we took away all of the smokers and ex-smokers from the pool of patients, lung cancer would rank seventh among the leading types of cancer afflicting the U.S. public.

Two-thirds of nonsmokers now battling the disease are women. That could be a function of statistical probability, some researchers say. Women in the general population smoke less than men and would probably represent the majority of any group of nonsmokers, including those with cancer.

Still, some studies raise the possibility that women may actually be more susceptible.

Stanford University oncologist Heather A. Wakelee headed up a 2007 study that found lung cancer rates among "never smokers" ranged from 4.8 to 13.7 per 100,000 men in a year, and 14.4 to 20.8 per 100,000 women.

"Those of us who treat the disease get a sense that these incidence rates for nonsmokers are increasing," Wakelee said. "But getting firm numbers is tricky" because the national cancer registry does not collect data on patients' smoking habits.

"What is causing these cancers in people who don't smoke? We don't know, and I doubt we'll ever find a particular cause," said oncologist Ramaswamy Govindan at the Washington University School of Medicine in St. Louis.

"It could be genetic, or a combination of factors. ... It's mostly bad luck. A random thing." Never smoked

In recent years, scientists have been examining the role of estrogen in the spread of lung cancer and its potential treatment.

Joan Schiller, deputy director of the Simmons Cancer Center in Texas, told the American Society of Clinical Oncologists in a 2010 interview: "This is such a relatively new field, we're just beginning to explore all the options. ... Perhaps estrogen is driving lung cancer in some people, just as estrogen drives breast cancer in some people."

If so, estrogen receptors could be targeted in therapy to drive the cancer out, she said.

Crizotinib, developed by Pfizer under the brand name Xalkori, has been found to shrink or stabilize tumors in patients carrying a gene mutation known as ALK, or anaplastic lymphoma kinase.

The U.S. Food and Drug Administration sped up approval of the oral drug for some patients diagnosed with non-small-cell lung cancer after weighing the drug's success in attacking other kinds of cancer.

As for the emotional toll of hearing she has lung cancer -- and being clueless to how she got it -- Gall resists thoughts that might distract from her goal to get well.

"I try not to dwell on the why because it just takes you down a rabbit hole, and that's not good," she said. "I try to look forward and not backward."