___________________________________________________________________________ Colorectal Cancer
Note: The National Cancer Institute states that history of colorectal cancer in a first-degree relative, especially before 55 years of age, approximately doubles the risk [1]. The Institute suggests that the benefit of screening might be improved by tailoring the recommended screening test to the patient’s degree of risk [1]. In response to rising rates of colorectal cancer among persons younger than 50 years of age, the U.S. Preventive Services Task Force (USPSTF) lowered its recommended age of initiation of screening to all adults 45 years of age, though the strength of recommendation is slightly lower than for those 50 years of age and older [122]. Clinical Considerations and Best Practice Advice for Colorectal Cancer Screening Based on limited evidence, the USPSTF does not make a sepa- rate, specific recommendation on colorectal cancer screening in Black adults, and modeling results also do not support dif- ferent screening strategies by race [122]. Other organizations, such as the U.S. Multi-Society Task Force, recommend start- ing screening in Black adults at 45 years of age while starting screening at age 50 years for persons of other races [166]. The USPSTF recognizes the higher colorectal cancer incidence and mortality in Black adults and strongly encourages clinicians to ensure their Black patients receive recommended colorectal cancer screening, follow-up, and treatment [122]. Recommended Colorectal Cancer Screening Intervals Clinicians should select the screening test with the patient on the basis of a discussion of benefits, harms, costs, availability, frequency, and patient preferences. The ACP recommends that patients between 50 and 75 years of age with average risk should be screened [85]: • Every 10 years for colonoscopy • Every 10 years for flexible sigmoidoscopy, plus iFOBT every 2 years • Every 2 years for high-sensitivity gFOBT or iFOBT These recommended intervals, especially for colonoscopy, are based on the assumption of optimal patient preparation and operator performance in the initial screen, allowing removal and biopsy of all polyps and detection of any precancerous lesion. Inadequate colonoscopy performance and resultant failure to detect adenomas or precancerous lesions places the patient at much greater risk of developing colorectal cancer (referred to as interval colorectal cancer) and renders the recommended interval unsafe [133]. Recommended Colonoscopy Surveillance after Screening and Polypectomy The timing of follow-up surveillance colonoscopy after initial colorectal cancer screening colonoscopy is an essential compo- nent of colorectal cancer prevention ( Table 5 ). Adenomatous polyps are cancer precursor lesions and the most common neoplasm found during colorectal cancer screening. Their detection and removal reduces colorectal cancer incidence
RECOMMENDED SURVEILLANCE INTERVALS FOR AVERAGE-RISK PATIENTS a Baseline Colonoscopy Findings Surveillance Interval No polyps (normal) 10 years 1–2 tubular adenomas <10 mm 7 to 10 years 3–10 tubular adenomas <10 mm 3 to 5 years 5-10 tubular adenomas <10 mm 3 years One or more tubular adenomas ≥10 mm 3 years One or more villous adenomas 3 years Adenoma with high-grade dysplasia 3 years <10 adenomas on single examination 1 year Piecemeal resection of adenoma ≥20 mm 6 months Serrated lesions
Sessile serrated polyp(s) <10 mm with no dysplasia ≤20 hyperplastic polyps in rectum or sigmoid colon <10 mm Piecemeal resection of sessile serrated polyp(s) ≥20 mm
10 years
6 months
a Strong recommendation Source: [167]
Table 5
and mortality, but patients with adenomas have heightened risk of developing interval cancers (metachronous adenomas or colorectal cancer) within three to five years of colonoscopy and polypectomy [167]. The basis for recommended time intervals between screening and surveillance colonoscopy should involve evidence that examinations prevent interval cancers and cancer-related mortality. Interval diagnosis of advanced adenomas has been used as a surrogate marker for colorectal cancer incidence or mortality. The U.S. Multi-Society Task Force guidelines for post-polypectomy surveillance in average-risk patients empha- size use of baseline colonoscopy findings for risk stratification, which is clustered into two groups [168]: • Low-risk adenomas: One to two tubular adenomas <10 mm • High-risk adenomas: Adenoma with villous histology, high-grade dysplasia, size ≥10 mm, or numbering three or more The British Society of Gastroenterology surveillance guidelines categorizes patients into three risk groups [169]: • Low risk: One to two adenomas <10 mm • Intermediate risk: Three or four small adenomas, or one adenoma ≥10 mm • High risk: More than five small adenomas, or three or more adenomas with at least one ≥10 mm
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