Colorectal, in full.

Polyposis syndromes are now governed by ACG 2026 (Mankaney G, Idos GE, Stoffel EM, Weiss JM, Shah S, Qayed E, Harnegie MP, Burke CA; Am J Gastroenterol 2026;121(9):2086-2120, GRADE). For polyposis, it replaces the 2015 ACG hereditary GI cancer guideline (Syngal et al.), Recommendations 10-11. Germline multigene panel testing is recommended for anyone with 20 or more cumulative lifetime colorectal adenomas (strong recommendation) and suggested for 10-19 adenomas (conditional, because the yield is lower). The 2015 polyposis testing trigger was more than 10 adenomas. Asymptomatic APC carriers, biallelic MUTYH carriers, and untested people at risk for AFAP or MAP should have a baseline colonoscopy by age 18-20. Colonoscopy then repeats every 1-3 years depending on the histology, size and number of polyps. It moves to every 3-6 months when there are many or large polyps, or high-grade dysplasia. This replaces the 2015 schedules of annual sigmoidoscopy/colonoscopy from puberty for classic FAP, colonoscopy every 1-2 years from the late teens for AFAP, and from age 25-30 for MAP. Whether at-risk children in classic-FAP families still start younger is not stated in the excerpt available at review; confirm against the full text. For FAP, AFAP and MAP, upper endoscopic surveillance that includes viewing the duodenal papilla is suggested over no surveillance (Recommendation 8, conditional). Duodenal management is still staged by Spigelman, which has acknowledged limits in sensitivity for duodenal and papillary cancer. The 2026 starting age and intervals for upper endoscopy are not stated in the excerpt available at review. The choice of operation (total colectomy with IRA, IPAA, or end ileostomy) is individualized by genotype, polyp distribution, cancer status, comorbidity and preference, with early referral to an experienced colorectal surgeon. IRA is generally favored with up to about 20 rectal adenomas and IPAA above that, though this is not a fixed cutoff. The rectum or pouch should be checked endoscopically every year after IRA or IPAA. Chemoprevention is recommended against as a substitute for colectomy when surgery is indicated. Whether 2026 keeps annual thyroid ultrasound is not stated in the excerpt available at review. Lynch syndrome and serrated polyposis syndrome are outside the 2026 document, so the Lynch and SPS parts of the standard on file were not re-verified here: Lynch colonoscopy every 1-2 years from age 20-25, gyn and upper-GI surveillance, and SPS colonoscopy every 1-3 years with removal of polyps over 5 mm.

Two 2026 AGA expert reviews now take precedence over the ACG 2021 guideline on several points. They are the AGA Clinical Practice Update on CDI in adults (Clin Gastroenterol Hepatol 2026; 14 best practice advice statements) and the AGA update on CDI in IBD (Gastroenterology 2026; 12 statements). Neither grades its statements with GRADE. DIAGNOSIS: CDI is a clinical diagnosis that needs compatible symptoms (about 3 or more unformed stools in 24 h) plus supportive lab testing. A multistep algorithm is preferred: a sensitive test (GDH or NAAT), then toxin EIA. A NAAT+/EIA- result should be read with caution, and patients with discordant results but high clinical suspicion should still be treated. SEVERITY: classify hospitalized patients at diagnosis. Severe is WBC >15,000/µL and/or creatinine >1.5 (ACG: >1.5 mg/dL; one secondary summary of the AGA text reports >1.5 times baseline). Fulminant is shock, ileus, or megacolon. INITIAL NONFULMINANT EPISODE (nonsevere or severe): fidaxomicin 200 mg twice daily for 10 days is favored first-line because of its narrower spectrum and lower recurrence. Oral vancomycin 125 mg four times daily for 10 days is an acceptable alternative. Metronidazole should not be used outside fulminant disease, which removes the ACG 2021 low-risk metronidazole option. Do not use cholestyramine or other bile-acid binders as monotherapy or alongside vancomycin or fidaxomicin. FULMINANT: manage with a multidisciplinary team. Give oral or enteral vancomycin 500 mg every 6 hours plus IV metronidazole 500 mg every 8 hours, and add rectal vancomycin 500 mg every 6 hours if ileus is present. Consider multi-dose FMT by lower endoscopy. The licensed products (fecal microbiota, live-jslm; fecal microbiota spores, live-brpk) are not approved for severe or fulminant CDI. After severe or fulminant CDI, keep the patient on suppressive vancomycin until a final outpatient FMT. FIRST RECURRENCE (within 8 weeks of finishing therapy): tapering/pulsed vancomycin or fidaxomicin, plus a recurrence-risk assessment and consideration of microbiota restoration. MICROBIOTA-BASED THERAPY (FMT or the licensed products): offer after treatment of a second recurrence. Consider it after an initial episode or first recurrence in patients at high risk of further recurrence or with a severe or refractory episode. SUPPRESSION: consider prolonged low-dose vancomycin 125 mg daily for patients with multiple recurrences who cannot receive or have failed microbiota-based therapy, have limited life expectancy or ongoing comorbidities, or need frequent systemic antibiotics. PREVENTION: do not use vancomycin prophylaxis during systemic antibiotics in the general population. Do not use probiotics for primary or secondary prevention. Encourage a high-fiber diet. Do not stop a PPI that has a legitimate indication, but review its use. Counsel patients with prior CDI to avoid unnecessary antibiotics. Use barrier precautions and EPA-approved sporicidal disinfection. No routine test of cure: retest only for persistent or worsening diarrhea. Bezlotoxumab does not appear in the AGA statements (Merck discontinued it in January 2025). IBD (AGA 2026): test for CDI in IBD patients with new or worsening diarrhea, including those with a pouch or ileostomy, using a multistep toxin-based assay. Treat a first episode preferentially with fidaxomicin, or vancomycin if fidaxomicin is unavailable or too costly. Never use metronidazole. Continue necessary IBD immunosuppression during CDI, and steroids may be used if needed. If symptoms persist after 48-72 h of treatment, consider endoscopy to assess IBD activity and CMV. Offer microbiome-based therapy after at least one recurrence. No probiotics. Oral vancomycin prophylaxis may be considered during systemic antibiotics in IBD patients with prior CDI. The summaries reviewed did not mention the ACG 14-day minimum vancomycin course in IBD.

U.S. Multi-Society Task Force (2017 guideline, revised by the 2022 focused update on age to start and stop): offer average-risk colorectal cancer screening to everyone aged 45-75. Screening at 45-49 is a weaker recommendation than at 50-75. Colonoscopy every 10 years and annual FIT are the Tier 1 cornerstones. Tier 2 alternatives are multi-target stool DNA every 3 years, CT colonography every 5 years, and flexible sigmoidoscopy every 5-10 years. Capsule colonoscopy every 5 years is Tier 3. Any abnormal non-colonoscopy test requires a diagnostic colonoscopy, and a stool test should not be offered to a patient who would decline follow-up colonoscopy. Patients who are up to date with negative prior screening, particularly a high-quality colonoscopy, may consider stopping at 75 or when life expectancy is under 10 years. Decisions at 76-85 are individualized by health and prior screening, and screening after 85 is not recommended. The American Cancer Society's May 2026 guideline agrees on the 45-75 range, no screening after 85, and colonoscopy as the preferred option. It adds the next-generation mt-sDNA test and the multitarget stool RNA test (ColoSense), both every 3 years, and it adds an FDA-approved blood-based cfDNA test (Shield) only for people who decline or do not complete visual or stool screening. ACS says a positive stool or blood test should be followed by colonoscopy, preferably within 6 months. The 2026 ASGE paper on follow-up after an abnormal stool test is an implementation review (navigation, tracking, direct-access colonoscopy), not a new screening guideline.