From the Guidelines
Colonoscopy screening should generally begin at age 45 for average-risk individuals, as recommended by the most recent guidelines from the National Comprehensive Cancer Network (NCCN) in 2024 1. This recommendation is based on the increasing incidence of colorectal cancer in individuals under 50, with approximately 43% of early-onset diagnoses occurring in those aged 45-49 years. The NCCN guidelines also suggest that individuals with a family history of colorectal cancer or advanced polyps in a first-degree relative should start screening earlier, typically at age 40 or 10 years before the age of diagnosis of the youngest affected relative, whichever comes first. Some key points to consider when determining when to start colonoscopy screening include:
- Average-risk adults should begin screening at age 45, with a strong recommendation to screen adults between ages 50 and 75 years 1
- Individuals with a family history of colorectal cancer or advanced polyps should start screening earlier, at age 40 or 10 years before the age of diagnosis of the youngest affected relative 1
- African Americans have higher colorectal cancer rates and may benefit from starting screening at age 45 or earlier 1
- Patients with inflammatory bowel disease like Crohn's or ulcerative colitis should begin screening 8-10 years after disease onset The preparation for colonoscopy typically involves a clear liquid diet the day before, followed by a bowel-cleansing solution like polyethylene glycol (GoLYTELY, MoviPrep) or sodium picosulfate. These guidelines aim to detect colorectal cancer early when treatment is most effective, as this cancer typically develops slowly from precancerous polyps that can be removed during colonoscopy.
From the Research
Guidelines for Colonoscopy
- The U.S. Multi-Society Task Force on Colorectal Cancer recommends that screening for colorectal cancer should begin at age 50 years in average-risk persons, except in African Americans in whom limited evidence supports screening at 45 years 2.
- For individuals with a family history of colorectal cancer or a documented advanced adenoma in a first-degree relative, screening by colonoscopy every 5 years is recommended, beginning 10 years before the age at diagnosis of the youngest affected relative or age 40, whichever is earlier 2.
- Patients with long-standing inflammatory bowel disease (IBD) involving at least one-third of the colon are at increased risk for developing colorectal cancer and should undergo surveillance colonoscopy using new approaches and techniques 3, 4, 5.
- The use of chromoendoscopy with targeted biopsies of visible lesions is supported by recent practice guidelines, rather than traditional random biopsies 3, 4, 5.
- Endoscopists are encouraged to endoscopically resect visible dysplasia and only recommend surgery when a complete resection is not possible 4.
Special Considerations
- For persons up to date with screening, who have prior negative screening (particularly colonoscopy), discontinuation of screening should be considered when they reach age 75 or have <10 years of life expectancy 2.
- Persons without prior screening should be considered for screening up to age 85, depending on age and comorbidities 2.
- Patients with IBD at increased risk for developing colorectal cancer should undergo surveillance colonoscopy using new approaches and techniques, and the management of patients with IBD who have a history of or ongoing active malignancy is an unmet need 6.