Women more at risk for colorectal cancer

Nov 1 2005

A new study of gender and risk factors for colorectal cancer reveals that while both tobacco and alcohol increase risk for colorectal cancer, women who smoke are at higher risk.

Researcher Anna L. Zisman, M.D. of Evanston Northwestern Health Care presented these findings at the 70th Annual Scientific Meeting of the American College of Gastroenterology. Another study presented at ACG of patients undergoing colonoscopy demonstrated that patients over 75 benefit from colorectal cancer screening in detecting cancer and potentially cancerous lesions and experience no more complications from colonoscopy than younger patients.

Smoking and alcohol use are well-established risk factors for colorectal cancer. According to Dr. Zisman, "Understanding interactions between genetic and environmental factors, such as smoking and alcohol use, is critical for colorectal cancer risk stratification, and will help us design effective screening strategies."

Dr. Zisman and her colleagues looked at women's susceptibility compared to men. Using the IMPAC Medical Registry Services Cancer Information Resource File, a large database from over 350 teaching and community hospitals, the investigators conducted a regression analysis of gender, tobacco and alcohol use. They found that while age of onset of colorectal cancer was slightly younger in males than females in the non-smoking/non-drinking group, current smokers had a markedly decreased age of presentation for both men and women. Similarly, alcohol use was associated with an earlier age of diagnosis in males and females. An assessment of the differential sensitivity to smoking and alcohol use in men and women revealed that women are sensitive to smoking as a risk factor for colorectal cancer but not alcohol. "We can see that while both men and women who use tobacco and alcohol are diagnosed with colorectal cancer at an earlier age, the effect of tobacco is significantly greater in women," said Dr. Zisman.

Most guidelines recommend that screening for colorectal cancer should begin at age 50 for individuals at average risk. "However there is no consensus regarding the age at which we should stop screening," commented Aaron Walfish, M.D. of Beth Israel Medical Center in New York. According to Dr. Walfish, "Older patients often have other health problems that increase the risk of undergoing endoscopy, so we need more evidence regarding the usefulness of screening in this older population. Our data support continued screening of elderly patients."

Dr. Walfish and his colleagues conducted a retrospective analysis of 178 patients 75 and older and 318 patients between ages 65 and 69. In both age groups, the researchers found that a similar percentage of patients had polyps or masses (43 percent in the 75 and older group vs. 42 percent in the 65 to 69 group), and that a similar percentage had larger polyps or masses (49 percent in the 75 and older group vs. 58 percent in the 65 to 69 group had polyps greater than or equal to 1 cm.) There were no complications from the screening procedure reported in either age group.