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For Women, The Most Deadly Cancer Isn't Breast

Like most women, I have always thought that the cancer that threatened me most was breast cancer. But a recent conversation with oncologist Dr. Natasha Leighl has challenged that assumption.
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Like most women, I have always thought that the cancer that threatened me most was breast cancer. But a recent conversation with oncologist Dr. Natasha Leighl has challenged that assumption. Though the incidence of breast cancer is more common, she told me, the mortality rate is far less: "90 percent more women die from lung cancer than breast cancer."

Dr. Leighl, a medical oncologist at Toronto's Princess Margaret Hospital, is also president of Lung Cancer Canada. In a recent briefing, Dr. Leighl revealed that lung cancer has now become the most commonly diagnosed cancer in Canada. Yet as a cancer, it receives too little attention. One reason is that it's still thought of as a man's disease. But while lung cancer mortality has fallen in men in the last 30 years, mortality rates have actually risen in women, she says.

The number of lung cancer deaths in women increased by more than 600 percent between 1950 and 1997; in recent years, lung cancer rates have declined by 3 per cent annually in men -- but only 1 per cent annually in women.

It was 50 years ago this past week that the U.S. Surgeon-General's report linked cigarette smoking to lung cancer. Cigarettes are still an attraction to young women who believe that smoking controls weight and helps them feel more self-confident and independent. But according to Dr. Leighl, women who don't smoke are at twice the risk of lung cancer as men who never smoked: "There is clearly a growing proportion of women who have never smoked and who are paying a very heavy price for it."

There are plenty of questions here. Are women more at risk because they may have genetic and hormonal differences that affect the development of lung cancer? What we do know is that non-smokers are at risk for lung cancer if they live or work with smokers. But second-hand smoke isn't the only carcinogen; there's also radon gas and certain environmental pollutants that raise risk.

As with other cancers, symptoms with this one arise when the cancer has spread: Coughing up blood, a persistent chest infection that doesn't clear with antibiotics, chest pains, shortness of breath and unexplained weight loss -- all of which are worrisome and all of which should be investigated.

One thing that's changed the landscape of lung cancer from hopeless to promising is lung cancer screening -- it's proving to be a successful strategy for finding and fighting early cancers in those who are at high risk. One study of 1,000 high-risk smokers (that is, smokers with a history of having smoked one pack daily for ten years and who were 55 years of age and older) performed by the Department of Medical Imaging at the University Health Network in Toronto showed that low-dose CT scans identified early-stage, small lung cancers. Separate studies from around the world have now reported the same.

"This is a game changer," says Dr. Leighl. "Right now, the five year survival rate is only 18 percent for lung cancer because we diagnose it too late. With low-dose CT screening, we can change the outcomes to look more like breast or prostate cancer -- a far more survivable disease with five year survival rates way about 50 percent.

"We have the technology and we know it is effective." But it is not widely available nor funded, says Dr. Leighl, adding that Lung Cancer Canada is calling for a national funded strategy that allows people at high risk in every province to be screened. South of the border, the U.S. Preventive Services Task Force has recommended that anyone with a high risk for developing lung cancer should be screened annually.

Screening saves lives, the U.S. report concluded. But will screening everyone at risk not also identify slow-growing tumors that are probably not dangerous to people during their lifetime? Yes -- and overdiagnosis is a problem that must be addressed.

Low-dose CT screening is the only test ever shown to reduce mortality in high-risk smokers, said a statement by the American College of Radiology which further stated that "overdiagnosis is an expected part of any screening program and does not alter these facts."

Dr. Leighl is strong in her belief that Canada needs screening for those at high risk, greater public drug coverage, and an increase in the availability of targeted therapies. More research dollars would also help: Lung cancer currently gets only seven percent of cancer-specific research funding despite causing more than 28 percent of all Canadian cancer deaths.

"We want everyone to help us promote greater public awareness and understanding," says Dr. Leighl. Lung cancer is not just a man's disease, she tells women: "If you have lungs, you are at risk."

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