Colonoscopies & Colon Cancer Screening

Gastroenterologist Dr. Yazan Abu Qwaider discusses the importance of colonoscopies.


I am a strong believer in preventive medicine. Just looking at medicine in general there are a lot of things we don't know. One of the major things is why patients develop colon cancer. We know there are some factors involved. There are some high-risk patients who have family members with colon cancer, but a majority of colon cancer cases are sporadic. So prevention is very important. All colon cancers start as a polyp, which is a tiny growth that grows very, very slowly over many, many years. And it doesn't give you any symptoms until it becomes large and aggressive enough. Symptoms might include weight loss and rectal bleeding; unfortunately, by that time, they are either advanced polyps or close to becoming cancerous. By performing colonoscopies, we can identify polyps, remove them, and reduce the risk of patients developing colon cancer. Colonoscopies have proven over the years to save people's lives, so I cannot emphasize enough their importance in preventive healthcare.

Why do patients get colonoscopies starting at age 50?

Why age 50? Because we looked at studies, and we found that the incidence of colon cancer increases with age. We found that patients who are age 60 and above usually have a higher detection rate of colon cancer, so that's why we went 10 years back. It usually takes about 10 years for polyps to grow from small polyps to cancer. By starting colonoscopies at age 50, you can take these polyps out and reduce the risk of patients developing colon cancer after age 60. We now know the polyp detection rate is 5% in patients age 50 and older. So patients have a one in 20 chance of having a pre-malignant polyp that could potentially become cancer when they get older, which is why age 50 is important.

How often should patients get colonoscopies after age 50?

We have guidelines from the American College of Gastroenterology and the American Cancer Society. The consensus is that if you're 50 and your colonoscopy is clear of polyps you're good for 10 years. For patients who have polyps, there are certain considerations, such as the size and pathology? The rule of thumb is if you find one polyp, the guidelines say you need a colonoscopy in five years. If you find a polyp with a certain pathology or the patient has a family history of colon cancer, we're talking here average risk. If you find two polyps, the recommendations are you come back for a colonoscopy in three years. I have taken large, aggressive polyps out, and I had my patients come back in three to six months because I want to look at the site and make sure I have removed the entire polyp. I can perform an endoscopic mucosal resection, which is taking large polyps and saving the patient from having surgery. If they come back clean, we're good. If they come back and the polyp has grown back again, then we're looking at surgery.