Colon cancer, also known as colorectal cancer, doesn’t appear overnight. In most cases, cancer begins as a small growth in the lining of the colon or rectum called a polyp. These polyps are often not cancerous at first, but over time—usually over 10 to 15 years—some can slowly turn into cancer. This long, silent development period is why screening (e.g. colonoscopy) is so effective: it allows doctors to detect and remove precancerous polyps before they have the chance to become dangerous.
The most common pathway to colon cancer is the adenoma-carcinoma sequence:
Normal colon cells grow a benign polyp called an adenoma.
Over the years, genetic mutations accumulate.
Some polyps become dysplastic (abnormal) and eventually turn into invasive cancer.
Adenomas come in various types, but we will not discuss that here. Risk factors that speed up the adenoma to cancer sequence include having a family history of colon cancer or some other cancers, inflammatory bowel disease like Crohn’s Disease or Ulcerative Colitis (NOT IBS, which is Irritable Bowel Syndrome), smoking, heavy alcohol use, obesity, and diets high in red or processed meats.
Current guidelines from the U.S. Preventive Services Task Force (USPSTF) recommend:
Average-risk adults start screening at age 45.
Continue screening every 10 years with colonoscopy, or more frequently with stool-based tests such as Cologuard or FIT.
People with a family history of colorectal cancer or certain genetic conditions may need to start screening as early as age 40 or 10 years before the youngest case in the family, whichever comes first.
If polyps are found, surveillance intervals may range from 3 to 5 years depending on size, number, and pathology.
Colon cancer generally develops slowly. We have a window of opportunity to prevent cancer, which is why we recommend regular screening. If you’re 45 or older—or have risk factors—talk to your healthcare provider about which screening method is right for you. Early detection can save your life.
Prevention starts with screening—don’t wait.
Until next time, that’s just the way the anus wrinkles.
