Colorectal cancer screening aims to find cancer early or detect polyps before they turn into cancer. Options include stool-based tests, colonoscopy and CT colonography. Many guidelines recommend average-risk adults begin screening around age 45 to 50. People with a family history or certain conditions may need earlier and more frequent screening.
Why Screen?
- Most colorectal cancers start as polyps
- Removing polyps prevents cancer
- Early cancers are easier to treat
- Many early cancers have no symptoms
Screening Options
Faecal immunochemical test (FIT)
- Detects hidden blood in stool
- Done at home
- Usually repeated every year
- A positive result needs colonoscopy
Stool DNA test
- Detects blood and abnormal DNA
- Done every one to three years where available
Colonoscopy
- Examines the entire colon
- Polyps can be removed during the test
- Needs bowel preparation and often sedation
- Usually every ten years if normal
CT colonography
- Uses a CT scan to create images of the colon
- Needs bowel preparation but no sedation
- Usually every five years
- Abnormal results need colonoscopy
Flexible sigmoidoscopy
- Examines the lower part of the colon
- Less commonly used alone
When Should Screening Start?
- Average risk: often from 45 to 50
- Family history: often earlier, such as 40 or ten years before the youngest affected relative
- Genetic syndromes or inflammatory bowel disease: much earlier and more frequently
Who Is at Higher Risk?
- Family history of colorectal cancer or polyps
- Lynch syndrome or familial adenomatous polyposis
- Ulcerative colitis or Crohn's disease
- Previous polyps or colorectal cancer
Symptoms Mean Testing, Not Screening
If you have rectal bleeding, change in bowel habits, weight loss or anaemia, you need diagnostic tests, not routine screening. See a doctor promptly.
Key Takeaways
- Screening prevents and detects colorectal cancer early.
- FIT is simple and done yearly.
- Colonoscopy can remove polyps.
- Screening often starts at 45 to 50.
- Higher-risk people need earlier screening.
Final Thoughts
Colorectal cancer is one of the most preventable cancers through screening. Choose a test with your doctor and stay on schedule. For colorectal assessment, you can consult Dr. Varadharajan, a surgical oncologist in Chennai.
