When should colon cancer be considered in a patient?

When to Consider Colon Cancer

Colon cancer should be considered in all adults beginning at age 45 years for average-risk individuals, with screening starting at age 40 or 10 years before the youngest affected relative's diagnosis in those with a family history of colorectal cancer. 1, 2

Screening by Age and Risk Category

Average-Risk Adults

Begin screening at age 45 years for all asymptomatic adults at average risk, defined as those without prior colorectal cancer, adenomatous polyps, inflammatory bowel disease, or known genetic syndromes. 1, 2

• The USPSTF provides a Grade A recommendation (substantial net benefit) for screening ages 50-75 years and a Grade B recommendation (moderate net benefit) for ages 45-49 years. 1
• The American Gastroenterological Association strongly recommends screening for age 50 and older based on high-quality evidence, with a weaker recommendation for ages 45-49 based on increasing colorectal cancer incidence in younger adults. 2
• This recommendation reflects that 10.5% of new colorectal cancer cases now occur in persons younger than 50 years, with incidence in adults aged 40-49 increasing by almost 15% from 2000-2002 to 2014-2016. 1

High-Risk Populations Requiring Earlier Consideration

Family History of Colorectal Cancer:

• Begin screening at age 40 or 10 years before the age of diagnosis of the youngest affected relative, whichever comes first, if a first-degree relative (parent, sibling, or child) had colorectal cancer or adenomatous polyps. 1, 2
• If the relative was diagnosed before age 55 with colorectal cancer or before age 60 with an adenomatous polyp, special efforts should be made to ensure screening occurs. 1
• Use colonoscopy every 5 years (not other screening modalities) for those with a first-degree relative diagnosed before age 60 or two first-degree relatives diagnosed at any age. 3

Hereditary Syndromes:

• Familial Adenomatous Polyposis (FAP): Offer flexible sigmoidoscopy annually beginning at puberty after genetic counseling and testing. 1
• Hereditary Nonpolyposis Colorectal Cancer (Lynch Syndrome): Begin colonoscopy every 1-2 years starting between ages 20-30, then annually after age 40, or 10 years before the youngest affected relative's diagnosis. 1, 2

Inflammatory Bowel Disease:

• Consider surveillance colonoscopy for dysplasia in patients with longstanding, extensive ulcerative colitis or Crohn's colitis beginning 8 years after onset of pancolitis or 12-15 years after onset of left-sided colitis. 1, 4

Personal History:

• Patients with prior adenomatous polyps (especially large >1 cm or multiple polyps) require colonoscopy 3 years after initial polypectomy. 1
• Patients with resected colorectal cancer need complete colonoscopy within 1 year after resection if not done preoperatively. 1

African American Patients

Begin screening at age 45 years due to higher incidence rates and earlier age of onset in this population. 5, 3, 4

When to Stop Screening

Stop screening at age 75 years for individuals who are up to date with screening and have had negative prior screening tests, particularly a negative colonoscopy. 1, 2, 5

• For adults aged 76-85 years who have never been screened, consider individualized screening decisions based on overall health status, life expectancy greater than 10 years, and absence of severe comorbidities. 1, 2, 5
• Discontinue screening after age 85 years as harms outweigh benefits regardless of prior screening history. 2, 5
• Stop screening when life expectancy falls below 10 years due to comorbidities, regardless of age. 1, 2, 6

Clinical Presentation Requiring Immediate Evaluation

Do not delay evaluation of symptomatic individuals regardless of age, especially those with:

• Rectal bleeding or hematochezia 2
• Iron deficiency anemia 1
• Change in bowel habits 1
• Unexplained weight loss 1
• Abdominal pain or obstruction 1

These symptoms warrant thorough diagnostic evaluation including colonoscopy, even in patients under age 45. 3

Screening Test Selection

First-tier options (strongest recommendation):

• Colonoscopy every 10 years 2, 3
• Annual fecal immunochemical test (FIT) 2, 3

Second-tier options for those declining first-tier tests:

• Flexible sigmoidoscopy every 5-10 years 2
• CT colonography every 5 years 2
• FIT-fecal DNA every 3 years 2

Use colonoscopy specifically (not other modalities) for high-risk patients with family history or hereditary syndromes. 1, 3

Common Pitfalls to Avoid

• Do not continue screening beyond age 85 when evidence consistently shows harms outweigh benefits. 2, 5
• Do not use serum tests, urine tests, or capsule endoscopy for routine colorectal cancer screening due to limited evidence. 1, 6
• Do not delay diagnostic evaluation in symptomatic young adults under age 45 with concerning symptoms, as colorectal cancer incidence is rising in this population. 1, 3
• Do not stop screening prematurely in healthy individuals aged 50-75 without prior screening, as 31% of eligible adults remain not up to date with screening. 1