Smoking increases risk of precancerous colorectal lesions in women more than in men

Men are more likely to develop colorectal cancer or its precursors than women. A new study conducted by MedUni Vienna shows that known risk factors do not explain this difference between the sexes. However, the research team led by Monika Ferlitsch was able to confirm that smoking significantly increases the risk of developing the precursors of colorectal cancer and have shown that the habit endangers women more than it does men. The results also emphasise the importance of colonoscopy as a preventive measure.

In Austria, approximately 5,000 people every year develop a malignant colorectal tumour. A large number of these cases could be averted by a preventive colonoscopy, because this procedure is able to identify and remove the precursors of colorectal cancer, so-called adenomas. It is interesting that men are twice as likely to develop adenomas than women.

In a recently published study, a team led by Monika Ferlitsch from the Department of Medicine III and Comprehensive Cancer Center of MedUni Vienna and Vienna General Hospital, investigated whether this difference could be explained by lifestyle factors. Ferlitsch: "We wanted to know whether men possibly led a less healthy lifestyle, which could explain the reason for their higher risk of colorectal cancer. So far there are very few gender-specific data available for the colon but such data are becoming increasingly important for developing prevention plans.

25,409 patients were involved in the study, 50.8% of whom were women. The first stage involved assessing traditional risk factors such as Body Mass Index, alcohol consumption, smoking, cholesterol level, blood glucose and blood pressure and then performing a colonoscopy.

Increased risk among men unexplained, smoking promotes tumours in general

The results are surprising: a person's gender seems to have more influence upon whether they develop colorectal cancer, or its precursors. It would appear that lifestyle is of secondary importance in this context. Smoking is the one exception to this. Smoking increases the probability of developing adenomas in both genders. In men, the risk of adenomas increases by 46% over non-smokers; in women by 76%; the risk of advanced adenomas is 100% higher in women who smoke than in those who don't. The researchers have not, as yet, discovered the reasons for this.

Says Ferlitsch, also in view of World Bowel Health Day on 7 November: "Since we are unable to assess the probability of a person developing colorectal cancer or its precursors on the basis of risk factors alone, colonoscopy is still the means of choice when it comes to preventing this type of cancer. Both men and women over 50 should have a regular colonoscopy."