Both women and men who are heavy smokers have twice the risk of colorectal cancer or an advanced colon polyp as people who never smoked. However, women who smoke less have the same risk as men who are heavier smokers.
In a recent study of more than 2,700 men and women, heavy smokers were divided into two groups:
- Heavy exposure A: People who were still smoking or had quit within the last ten year and had exposure of less then 30 pack years.
- Heavy exposure B: Those still smoking or quitting less than ten years before and with exposure of 30 pack years or more.
Pack years are calculated by the number of packs smoked each day times the number of years an individual has smoked. Thirty pack years are equivalent to smoking a pack of cigarettes a day for thirty years or two packs a day for fifteen years.
- Men who were heavy smokers but smoked less than 30 pack years had about a 25 percent increased risk of serious precancerous polyps or cancer compared to never smokers, but women who smoked the same amount had twice the risk.
- Men who smoked thirty or more pack years had almost three and a half times the risk, while women continued to have a double risk.
- Overall, both male and female heavy smokers — those who were still smoking or had quit less than ten years ago — had twice the risk of serious colon neoplasia as those who never smoked.
Joseph C. Anderson, M.D. from the University of Connecticut Cancer Center and Colon Cancer Prevention Program, reporting at the American College of Gastroenterology Annual Scientific Meeting in Orlando concluded,
Although males and females have a similar 2 fold risk for significant colorectal neoplasia from smoking, women require less exposure in pack years to have an increase in risk.
SOURCE: Anderson J.C. et al., Smoking and Colorectal Neoplasia: Women Require Less Tobacco Exposure For Similar Increased Risk As Compared To Men, American College of Gastroenterology Annual Scientific Meeting, October 6, 2008.