If you have had a colonoscopy and were told that a polyp was found in your colon and removed, you may have been horrified, especially if your doctor described it as a "precancerous" growth. Most likely what you had was an adenoma. Here's the good news behind that disconcerting news: Though colorectal cancer usually starts in adenomas and some other less common types of polyps, the vast majority of these growths are benign and will never progress to cancer. And the polyps that do become malignant take many years to do so. Thus, it is misleading and alarmist to call these very common growths "precancers."
Scoping out the facts
- About 15 to 25 percent of people have at least one adenoma by age 50, when screening for colorectal cancer typically should start.
- Adenomas and other polyps increase with age, and up to half of people will develop them in their lifetimes. The detection rate has been rising primarily because new high-resolution endoscopes are able to find smaller and flatter polyps.
- It's estimated that about 5 percent of all adenomas would eventually develop into cancer if not removed. Keep in mind, that is lifetime risk. The risk is about 1 percent per year for large adenomas, on average, and even lower for small ones. If you've ever had an adenoma (or certain other types of polyps) removed, you'll need to have more frequent colonoscopies. Discuss this with your doctor, particularly since some types of polyps, such as small "hyperplastic" polyps, are not associated with increased cancer risk and thus do not require more frequent surveillance.
Screening saves livesWe don't mean to sound Pollyannaish about polyps. Colon cancer, which usually starts as a benign polyp, is still the second biggest cancer killer in the U.S. (after lung cancer), claiming nearly 50,000 lives a year. That's largely because about one-third of us don't get screened as recommended, allowing that small percentage of adenomas to progress eventually to invasive cancer. There may be debate about the benefits of PSA screening tests for prostate cancer and even about mammograms, but there is none about getting screened for colorectal cancer.
Speak with your health care provider about the options: Colonoscopy every 10 years is one choice, but there are others, notably annual screening for blood in the stool by a fecal immunochemical test (FIT); if blood is detected, a colonoscopy will be required. For more about colorectal screening, go to Do You Need a Colonoscopy?