Colonoscopy, Colorectal Cancer Screening, and Surveillance
Colonoscopy and surveillance
Colonoscopy quality is measured, not assumed. Cecal intubation should exceed 90% (85% in screening), with photo documentation of the appendiceal orifice and ileocecal valve; terminal ileum intubation is desirable in selected cases. Withdrawal should take at least 6 minutes in screening, with careful mucosal washing and inspection behind folds, in the flexures, and in the rectum on retroflexion.
Polypectomy technique depends on size and morphology. Cold snare is preferred for sessile lesions under 10 mm; cold forceps alone is inadequate because it leaves residual tissue. Larger lateral spreading lesions are removed by piecemeal EMR, with margin ablation or snare-tip soft coagulation, and surveillance at 3-6 months for piecemeal resections. Paris and LST classifications guide resection choice.
Screening options for average-risk adults starting at 45 include colonoscopy every 10 years, annual FIT, FIT-DNA every 3 years, CT colonography every 5 years, and flexible sigmoidoscopy every 5 years. A positive FIT mandates colonoscopy regardless of a repeat FIT result. Family history of colorectal cancer in a first-degree relative before age 60 means starting at 40 or 10 years before the relative diagnosis, whichever is earlier, and repeating every 5 years. Lynch syndrome and serrated polyposis require syndrome-specific programs.
Surveillance after polypectomy follows baseline findings: 1-2 tubular adenomas under 10 mm, 7-10 years; 3-4 small adenomas, 3-5 years; 5 or more, or any lesion at least 10 mm, or high-grade dysplasia, about 3 years. Serrated lesions have separate intervals.
Worked example: a 55-year-old has three 5 mm tubular adenomas-surveillance at 3-5 years, not 10. A 6 mm sessile polyp should be cold-snared, not cold-biopsied.