Smoking Exposure Now Linked to Colon, Breast Cancers

Dec. 4 -- THURSDAY, Dec. 3 (HealthDay News) -- Add colorectal cancer to the list of malignancies caused by smoking, with a new study strengthening the link between the two.

And other studies are providing more bad news for people who haven't managed to quit: Two papers published in the December issue of Epidemiology, Biomarkers & Prevention, a themed issue on tobacco, strengthen the case for the dangers of secondhand smoke for people exposed to fumes as children and as adults.

Inhaling those secondhand fumes may raise a woman's odds for breast cancer or a child's lifetime risk for lung malignancies, the studies found.

All of the findings, while grim, could be useful in the war against smoking, experts say.

"With the FDA [U.S. Food and Drug Administration], we're hoping this will be a significant tool to controlling tobacco, although it could get bogged down in so many different ways," said Dr. Peter Shields, deputy director of the Georgetown University Lombardi Comprehensive Cancer Center and senior editor of the journal in which these papers appeared. "The FDA is going to have to make a lot of tough decisions about how to regulate tobacco, and the more science they have will help them."

Is this latest round of revelations going to change current screening recommendations? Probably not, at least not yet, Shields added.

One study found that long-term smokers have a higher risk of developing colorectal cancer, a finding that factored into the recent decision by the International Agency for Research on Cancer (IARC) to assert that there is "sufficient" evidence to link the two, up from its previous "limited" evidence.

"It took a long time to figure this out because the relationship [between smoking and colorectal cancer] is not as strong [as for some other cancers]," said Dr. Michael Thun, senior author of the study and vice president emeritus of epidemiology and surveillance research at the American Cancer Society. "The question was, is the association we're seeing really caused by smoking?"