Adenoma Detection Rates In Obese And Smoking Patients

At left, stained adenoma under the microscope.

By Nephron - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8273894

Here is a study showing higher detection rates for adenomas and serrated adenomas in obese and smoking patients undergoing colonoscopy. Adenomas are benign tumors that - if left in the colon - have a probability of turning into full-fledged cancer (e.g., for a given polyp, could be a 10% chance in 10 years). Therefore, when detected in endoscopic screening, adenomas are typically removed.  The more adenomas, the greater the chance for cancer, so it is not surprising that obese and smoking individuals tend to have higher rates of colorectal cancer, since they are developing more of the pre-cancerous adenomas.

This again underscores the fundamental importance of maintaining a healthy bodyweight and to refrain from smoking.  If you are already at a normal weight and do not smoke, great, keep it up; if not, lose weight and make every attempt to quit smoking.  In general people associate obesity with diabetes and smoking with lung cancer, and those associations are indeed correct; however, there are many, many diseases associated with both obesity and smoking - including colorectal cancer - so the health ramifications of weight control and no smoking are enormous.