Why the Lung Cancer Gender Gap?

Lung Cancer Rates Are Falling for Men, but Not for Women

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Mar. 7, 2005 -- Does lung cancerlung cancer affect men and women differently? Yes, a new study shows.

On one hand, women have better survival rates at every stage (or extent) of the disease. But fewer men are getting lung cancer than before, while women's rates are still dangerously high.

"Traditionally, lung cancer has been viewed as a disease of older, male smokers, but that is not necessarily the case," says University of Michigan researcher Gregory Kalemkerian, MD, in a news release.

Lung Cancer Falling Among Men

Just how big is the gender gap, and where is it headed?

Women account for 36% of lung cancer cases, says Kalemkerian's study. That means lung cancer still strikes more men than women.

But those numbers don't tell the whole story. A little history helps paint the big picture, and it's not a pretty sight for women.

Lung cancer rose among women between 1975 and 1991, peaking at 33 cases per 100,000 women. Ever since then, those numbers haven't budged much, says the study.

Not so for men. Their lung cancer rate has fallen since 1984. Back then, about 72 out of every 100,000 men had lung cancer. By 1991, the rate had dropped to 47 per 100,000 men.

If those trends continue, lung cancer will strike men and women equally by 2020, according to the study. The numbers are based on more than 228,000 lung cancer patients diagnosed from 1974 to 1999.

Better Survival for Women

More women than men survive lung cancer, says the study. That was true for every stage of the disease. But again, women's numbers weren't moving in a positive direction.

For example, the two- and five-year survival rates for people with localized cancer were about 12% better for women than men from 1975 to 1987. The survival rate is the percentage of men or women who are still living a period of time after they are diagnosed with lung cancer.

But during the next 11 years, women's survival advantage was virtually cut in half. Their edge dropped to 6%, says the study.

More women than men get surgery for their lung cancer, which may have helped their chances of survival, says the study.

More Cases Among Younger Women

A disproportionate number of younger women had lung cancer. Women made up 41% of patients younger than 50, the study shows.

That could be due to smoking, say the researchers. But data wasn't available on the patients' smoking habits.

The reasons for the gender gap still remain a mystery. It's possible that tobacco smoke affects men and women differently. According to the U.S. Department of Health and Human Services, 90% of all lung cancer deaths among women are from smoking.lung cancer deaths among women are from smoking.

But the link between smoking and lung cancer is "indisputable" for men and women alike, write the researchers.

The best way to prevent lung cancer is to never start smoking. If you smoke, the sooner you quitquit the better. Remember, it's never too late to quit.

Their study appears in the March issue of the journal CHEST.

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SOURCES: Fu, J. CHEST, March 2005; vol 127: pp 768-777. News release, American College of Chest Physicians.
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