No Symptoms Doesn’t Mean No Risk: Colon Cancer Screening Options You Should Know
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Colon cancer can develop quietly. Many people feel completely well, have no pain, no bleeding and no change in bowel habits — and still have precancerous polyps or early colorectal cancer. That is exactly why screening matters. Screening gives physicians the opportunity to find cancer earlier, when treatment is more effective, and in many cases, to prevent cancer by finding and removing precancerous polyps before they become dangerous.
Colorectal cancer remains one of the most important preventable cancers in the United States. The good news is that patients have more screening options than ever. The best test is the one that is appropriate for your risk level and actually gets completed on schedule.
Neal Kaushal, M.D., MBA, a board-certified gastroenterologist with INTEGRIS Health Medical Group Gastroenterology Edmond and gastroenterology section chief for INTEGRIS Health, explains what patients should know about colon cancer screening, when to start and how to choose the right option.
What is colon cancer screening?
Colon cancer screening is a preventive health strategy used to look for colorectal cancer or precancerous polyps before symptoms develop. A polyp is a growth that can form on the lining of the colon or rectum. Some polyps are harmless, but others can slowly turn into cancer over time.
That timeline creates an important opportunity. When polyps are found and removed during a colonoscopy, cancer may be prevented before it starts. When cancer is found early, treatment is typically more effective and outcomes are better.
Screening is not reserved for people who feel sick. In fact, the entire point is to evaluate patients before warning signs appear.
When should you start screening?
For adults at average risk, routine colorectal cancer screening should begin at age 45. Average risk generally means you do not have a personal history of colorectal cancer or certain types of polyps, inflammatory bowel disease, a known hereditary colorectal cancer syndrome or a strong family history of colorectal cancer.
Adults ages 45 to 75 should be screened regularly. For adults ages 76 to 85, the decision should be individualized based on overall health, prior screening history and patient preference. Some people in this age range may still benefit from screening, while others may not.
Patients at higher risk may need to start earlier than 45 or be screened more often. A family history is one of the most important reasons to talk with your physician early. In many cases, screening is recommended 10 years before the age at which a first-degree relative was diagnosed, or at age 40, whichever comes first.
Who is at higher risk?
Several factors can increase a person’s risk for colorectal cancer. Some are not under your control, such as age, family history and inherited genetic syndromes. Others are lifestyle-related and may be modified over time.
- A parent, sibling or child with colorectal cancer or advanced polyps
- A personal history of colorectal cancer or precancerous polyps
- Inflammatory bowel disease, including ulcerative colitis or Crohn’s disease involving the colon
- Certain inherited syndromes, such as Lynch syndrome or familial adenomatous polyposis
- A diet high in processed meats or frequent heavy intake of red meat
- Tobacco use, heavy alcohol use, obesity, diabetes and physical inactivity
Risk factors do not guarantee that someone will develop cancer, and having no obvious risk factors does not guarantee protection. That is why guideline-based screening is important even for healthy people.
Is colon cancer becoming more common in younger adults?
Yes. Colorectal cancer is increasingly being diagnosed in adults younger than 50. The reasons are not fully understood, and the medical community is still working to determine why this shift is happening.
Likely contributors include changes in diet, obesity, metabolic health, sedentary behavior, the gut microbiome and environmental exposures. Researchers are also studying possible links between colorectal cancer and emerging exposures such as microplastics, but that area remains investigational. It is important to discuss these possibilities carefully: they are reasonable research questions, not settled explanations.
For younger adults, the practical message is simple: do not ignore symptoms because of age. Rectal bleeding, persistent change in bowel habits, unexplained iron-deficiency anemia, unexplained weight loss, ongoing abdominal pain or a feeling that the bowel does not empty completely should be evaluated. Hemorrhoids are common, but they should not automatically be blamed for bleeding without appropriate medical assessment.
What screening options are available?
There are several accepted colorectal cancer screening options. Each has advantages, limitations and different follow-up requirements. Your doctor can help match the test to your risk level, medical history and preferences.
Colonoscopy
Colonoscopy is considered the most complete screening option because it allows the physician to examine the entire colon and remove polyps during the same procedure. For average-risk patients with a normal exam, colonoscopy is typically repeated every 10 years.
Colonoscopy requires bowel preparation and sedation, and patients need someone to drive them home afterward. The preparation is not anyone’s favorite part, but a high-quality bowel prep is critical. If the colon is not clean, small or flat lesions can be missed, and the exam may need to be repeated sooner.
FIT test
The fecal immunochemical test, or FIT, is a stool-based test that looks for hidden blood. It is done at home and typically repeated every year. FIT is convenient and does not require sedation or bowel prep.
The tradeoff is that FIT is primarily a cancer detection test, not a polyp-removal strategy. If the test is positive, a colonoscopy is required to identify the source of bleeding and remove polyps if present.
Stool DNA testing
Stool DNA testing looks for abnormal DNA markers and hidden blood in the stool. It is also completed at home and is generally repeated every three years for average-risk patients when results are negative.
Like FIT, a positive stool DNA test must be followed by colonoscopy. Stool-based tests are not intended for patients at high risk, including many patients with a strong family history, prior advanced polyps or inflammatory bowel disease.
CT colonography and flexible sigmoidoscopy
CT colonography, sometimes called virtual colonoscopy, uses imaging to evaluate the colon and is typically repeated every five years when used for screening. Flexible sigmoidoscopy examines only the lower part of the colon and may be an option in certain settings.
These tests may be useful for selected patients, but they have limitations. If a suspicious finding is seen, a traditional colonoscopy is still needed to remove polyps or biopsy tissue.
How should you prepare for screening?
Preparation depends on the test. Stool-based tests usually require minimal preparation. Colonoscopy requires dietary changes and a bowel cleansing regimen. Patients should follow the instructions closely and contact their care team if they have questions about medications, diabetes management, blood thinners or prior difficulty with bowel prep.
A successful screening strategy is not just about choosing a test. It is about completing the test correctly and following through on the next step if results are abnormal.
The bottom line
No symptoms does not mean no risk. Colorectal cancer often develops silently, and waiting for symptoms can mean waiting too long. Screening beginning at age 45 for average-risk adults is a key preventive step. People with a family history, concerning symptoms or higher-risk medical conditions should talk with their physician about whether they need earlier or more frequent testing.
Colonoscopy remains the most comprehensive option because it can detect cancer, find precancerous polyps and remove those polyps during the same procedure. Stool-based and imaging-based tests can also play an important role for appropriate average-risk patients, as long as abnormal results are followed by colonoscopy.
The best next step is to have a clear conversation with your doctor about your risk, your options and the screening plan that makes sense for you.
This article was medically reviewed by Neal Kaushal, M.D., MBA, a board-certified gastroenterologist in Oklahoma.
