A colonoscopy is a medical procedure used to examine the lining of the colon and rectum. Its primary purpose is to screen for colorectal cancer, a disease that often begins as non-cancerous growths called polyps. By identifying and removing these polyps, a colonoscopy serves as both a diagnostic tool and a preventive measure.
Standard Screening Age Guidelines
The standard recommendation for when men at average risk should begin colorectal cancer screening has recently shifted from age 50 to 45. This change was adopted by major health organizations, including the American Cancer Society and the U.S. Preventive Services Task Force, in response to a concerning rise in colorectal cancer incidence among younger adults. Starting screening at age 45 is now the widely accepted guideline for individuals considered to be at average risk for the disease.
An average-risk individual is defined as someone who has no personal or family history of colorectal cancer or certain types of polyps, no personal history of inflammatory bowel disease, and no known genetic syndromes that increase their risk. For men who choose a colonoscopy as their initial screening method and whose results are negative, the procedure typically needs to be repeated every 10 years. This interval reflects the slow progression of polyps into cancerous tumors.
Continuing regular screening is generally recommended through age 75 for men who are in good health and have a life expectancy of more than 10 years. For men between the ages of 76 and 85, the decision to continue screening should be made individually, taking into account their overall health, prior screening history, and personal preferences. Screening is generally no longer recommended for those over 85 years old.
Identifying Conditions That Lower the Screening Age
While age 45 is the standard for average-risk individuals, certain conditions classify a man as high-risk, necessitating that screening begin much earlier. A significant risk factor is a strong family history of colorectal cancer or advanced adenomatous polyps in a first-degree relative (parent, sibling, or child). In these cases, screening should often begin 10 years before the age at which the family member was diagnosed. For example, if a parent was diagnosed at age 45, the man should begin screening at age 35.
Personal medical history plays a large role, especially the presence of inflammatory bowel disease (IBD), which includes Crohn’s disease or ulcerative colitis. Individuals with IBD generally require colonoscopies, not other tests. Screening may start as early as eight years after their initial diagnosis, with follow-up procedures scheduled every one to three years.
Men with a known or suspected hereditary colorectal cancer syndrome are considered high-risk and must begin screening at a younger age. These genetic conditions include Lynch syndrome and Familial Adenomatous Polyposis (FAP).
Other factors requiring earlier or more frequent screening include a personal history of radiation to the abdomen or pelvic area to treat a prior cancer. Screening may start 10 years after the radiation was given or at age 35, whichever is later, and may be repeated every three to five years. A healthcare provider must determine the appropriate starting age and frequency for screening.
Comparing Colonoscopy to Alternative Screening Tests
The colonoscopy is considered the most comprehensive screening method because it inspects the entire colon and allows for the immediate removal of precancerous polyps during the procedure. However, several alternative options exist for initial screening for average-risk men. These alternatives serve as effective screening tools, but a positive result mandates a follow-up colonoscopy to confirm the finding and remove any discovered lesions.
The Fecal Immunochemical Test (FIT) detects hidden blood in the stool, a potential sign of cancer or polyps. This non-invasive, at-home test is typically performed every year. The multi-target stool DNA test (Cologuard) analyzes the stool sample for both blood and specific abnormal DNA markers shed by colon cells. This test is generally recommended every three years.
Direct visualization tests, which examine the colon’s structure, also offer alternatives to a full colonoscopy.
Direct Visualization Tests
A Flexible Sigmoidoscopy involves inspecting only the lower part of the colon and rectum. It is usually performed every five years, sometimes combined with an annual Fecal Immunochemical Test (FIT).
Computed Tomography (CT) Colonography, sometimes called a virtual colonoscopy, uses X-rays and computer technology to create images of the colon’s interior. This test is typically recommended every five years.
A key difference is that while these structural tests are effective for screening, only a colonoscopy allows for the removal of polyps during the procedure, making it both a screening and therapeutic intervention.