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Understanding Screenings

When should you have your first colonoscopy?

Written By Hatem Shoukeir, NH Gastroenterology

January 13, 2020

Colorectal cancer is the second most common cause of cancer death in men in the U.S. and third most common cause of cancer death in women. But these rates have declined since 1990, largely due to an increase in colorectal cancer screening. Colorectal cancer can be cured if it’s caught early, and the screening options are more accurate and comfortable than ever. Screening methods include colonoscopy, CT colonography, and stool testing like the FIT test and Cologuard. 

When and how often you should be screened depends on your level of risk.
  • An average-risk screening is for a patient who has no symptoms and no personal or family history of colorectal cancer.
  • A high-risk screening is for someone who has a family history of polyps (small clumps of cells growing together) or colorectal cancer.
  • Surveillance colonoscopy is performed in someone with a personal history of polyps, colorectal cancer, or an inflammatory bowel disease like Crohn’s disease.
  • Diagnostic colonoscopy is performed after a positive screening test, such as FIT or Cologuard, or for symptoms such as rectal bleeding.
It’s generally recommended that average-risk patients have their first screening at age 50 and repeat once every ten years. However, organizations like the American Cancer Society have recently started to suggest testing as early as age 45. But it’s not clear whether the benefit of early testing outweighs the harm, cost, and inconvenience to the patient.

It can be argued that the benefit of screening at a younger age is to find cancer at its earliest stage, when it is easiest to cure. Cancerous polyps can be removed during the colonoscopy. Earlier detection lowers the need for surgery and chemotherapy, which also lowers the cost of medical expenses that come with more advanced-stage treatment.

Age remains the best predictor to determine the need for screening. Those who are 55-59 years old have a five-fold risk of colorectal cancer over those who are not yet 50. While highly effective at detecting and curing cancer, a colonoscopy may have limited benefit to younger populations. A major concern of unnecessary, early screening is that it diverts resources away from the older population who are at higher risk. The more efficient and cost effective approach might be to assess 45-49-year-olds for their personal risk factors and defer those who are low risk until age 50. March 2022 update: The guidelines have recently changed, and doctors now advise everyone to begin screening at age 45.

What’s your risk?
Questions to discuss with your provider:
  • Do you have a direct relative who has had colorectal cancer or Lynch syndrome-related cancer before age 50?
  • Have you had colorectal cancer or polyps before age 50?
  • Do you have three or more relatives with colorectal cancer?
  • Other important factors to discuss include: high body mass index, metabolic syndrome, cigarette smoking, diet and use of certain medications.