For most adults, the typical recommendation is to start colonoscopy screening for colon cancer at age 45 if you are at average risk, and continue at regular intervals until about age 75.

Key ages at a glance

  • Start at 45 (average risk):
    Major guidelines now say adults at average risk should begin colorectal cancer screening at 45, lowered from the old standard of 50 because cancers are appearing more often in younger adults.
  • 45–75: routine screening years:
    In this age range, screening is strongly recommended because the benefit in preventing and catching cancer early is high.
  • 76–85: case‑by‑case decision:
    After 75, whether to continue depends on overall health, life expectancy, and how regularly you were screened before; it’s a shared decision with your doctor.
  • After 85: usually stop:
    Guidelines generally advise stopping routine screening after age 85, because the risks and burdens tend to outweigh the benefits for most people.

When to start earlier than 45

You may need screening before 45 if you are higher risk. Common reasons include:

  • A strong family history of colorectal cancer or advanced polyps (for example, a first‑degree relative diagnosed before 60).
  • Known genetic syndromes (such as Lynch syndrome or familial adenomatous polyposis).
  • Long‑standing inflammatory bowel disease affecting the colon (ulcerative colitis, Crohn’s colitis).
  • Certain hereditary cancer conditions or a history of abdominal radiation at a young age.

In these situations, doctors may suggest starting around age 40 or 10 years earlier than the age at which your youngest affected relative was diagnosed, whichever is first.

Colonoscopy vs other screening tests

“Colonoscopy age” often gets talked about as if colonoscopy is the only option, but guidelines now treat it as one of several screening tools:

  • Colonoscopy: Usually every 10 years if results are normal; lets doctors find and remove polyps in the same procedure.
  • Stool‑based tests: Such as FIT (yearly) or stool DNA‑FIT (every 1–3 years), with colonoscopy if anything abnormal shows up.
  • Imaging scopes: CT colonography or flexible sigmoidoscopy every 5 years in some strategies.

Even when you start with a home test, an abnormal result typically leads to a colonoscopy as the follow‑up step.

Why the age dropped from 50 to 45

In the last several years, experts have seen a sharp rise in colorectal cancer in people under 50 , including those in their 30s and early 40s.

  • Early‑onset colorectal cancer is now a leading cause of cancer death in people under 50.
  • Lowering the start age to 45 aims to catch and remove precancerous polyps earlier, before they turn into cancer.
  • At the same time, there is ongoing debate and research about whether to push screening even earlier for some groups (like starting at 40), balancing benefits, costs, and equity of access.

Mini “forum‑style” viewpoints

“I’m 44, no family history — should I wait?”
Many clinicians now say it’s reasonable to plan your first screening around your 45th birthday if you’re average risk, and to talk through whether a stool test or colonoscopy fits you best.

“My parent had colon cancer at 52. What about me?”
You may be advised to start 10 years earlier than their diagnosis age (around 42), or at 40, and then repeat on a schedule your doctor recommends.

“I’m over 75 and never had one.”
Screening can still be helpful in some healthy older adults, but it becomes a very individual decision, weighing your health, preferences, and how likely you are to benefit over the next 10+ years.

Simple rule of thumb

  • If you are average risk :
    • Plan to start screening at 45 , often with either a colonoscopy or a stool‑based test.
  • If you have risk factors or symptoms (blood in stool, unexplained weight loss, persistent change in bowel habits):
    • Do not wait for a “screening age” – contact a healthcare professional promptly for a diagnostic evaluation.

Information gathered from public forums or data available on the internet and portrayed here.