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.

ACG 2026 (Peery AF et al.; Am J Gastroenterol 2026;121(7):1549-1561; published 1 July 2026) is now the current US guideline. Its clinical content matches the standard on file. Classify diverticulitis by phenotype. UNCOMPLICATED is localized inflammation of colonic diverticula without abscess, perforation, stricture or fistula. CHRONIC/SMOLDERING is inflammation lasting weeks to months that partly or fully improves on antibiotics, then relapses soon after they stop. COMPLICATED means phlegmon, abscess or perforation, graded by the CT-based modified Hinchey scale (0, Ia, Ib, II, III, IV); strictures and fistulas are delayed complications. Hinchey 0-I is usually managed without surgery. Obtain CT at first presentation and in severe cases. Repeat CT may be unnecessary for a typical recurrence after a CT-confirmed prior episode without concerning features (severe pain, fever, vomiting, chills, abnormal exam). Keep a low threshold to image immunocompromised patients. ANTIBIOTICS: suggest against routine antibiotics for low-risk patients with acute uncomplicated diverticulitis (conditional, moderate certainty; four RCTs showed no effect on complications, recurrence, surgery, readmission or mortality). Low-risk means immunocompetent, hemodynamically stable, tolerating oral intake without SIRS, not frail, and able to follow up reliably as an outpatient. Give antibiotics for high-risk clinical or imaging features, immunocompromise, frailty or medical complexity, inability to tolerate oral intake, clinical worsening or prolonged symptoms, systemic inflammatory findings, or when safe outpatient management cannot be ensured. When used, give 4-7 days of oral therapy: amoxicillin-clavulanate 875/125 mg q12h or moxifloxacin 400 mg daily as monotherapy, or metronidazole 500 mg q8h plus TMP-SMX DS q12h, ciprofloxacin 500 mg q12h or levofloxacin 500 mg q24h. COLONOSCOPY after recovery: recommended after COMPLICATED diverticulitis to exclude a missed cancer or premalignant lesion (strong, moderate), usually about 6-8 weeks after recovery. After UNCOMPLICATED diverticulitis it is suggested only with alarm symptoms (unintentional weight loss, change in bowel habits, iron-deficiency anemia, bloody stools, persistent abdominal pain) or when colorectal cancer screening is not up to date (conditional, low). Colonoscopy can be deferred if a recent high-quality exam has excluded neoplasia. Do not scope routinely during the acute phase, but move earlier for alarm features such as ongoing bleeding, obstruction, or imaging concerning for malignancy. SURGERY: suggest surgical referral to discuss elective resection when recurrent uncomplicated diverticulitis significantly impairs quality of life (conditional, low). Base the decision on symptom burden, not episode count or preventing emergency surgery, and confirm the diagnosis by CT first. Resection lowers but does not eliminate recurrence: about 15% vs about 60% at 5 years. Without surgery, recurrence is at least 22% at 10 years after a first episode and at least 55% at 10 years after a second, and stays high after 3 or more. Risk of complicated disease is highest at the first episode and falls with recurrences. PREVENTION (all conditional): a healthy high-fiber diet (fruits, vegetables, whole grains, legumes; limit red meat, refined grains, trans fats, sweets); do not avoid nuts, corn, seeds or popcorn; avoid regular NSAID use unless clinically indicated; moderate heavy alcohol use; lose weight if overweight or obese; regular physical activity; stop smoking. Recommend AGAINST mesalamine (strong, moderate), probiotics (conditional, very low) and rifaximin (conditional, very low) to reduce recurrence.