Impact of complete colonoscopy after ischaemic colitis onset on colorectal neoplasm detection in patients without suspected coexistence of colorectal cancer on computed tomography: a retrospective analysis.

Objective: Ischaemic colitis is the most prevalent form of ischaemic enteritis and represents a major cause of acute lower gastrointestinal bleeding. Although the American College of Gastroenterology's clinical guidelines recommend colonoscopy after ischaemic colitis to screen for colorectal cancer, the actual detection rate of neoplastic lesions in patients without suspected malignancies on CT remains unclear. This study aimed to assess the efficacy of colonoscopy in detecting colorectal neoplasms after the resolution of ischaemic colitis.

Methods: This retrospective, single-centre, observational study included patients diagnosed with ischaemic colitis at the Isesaki Municipal Hospital in Japan between 2014 and 2023. Patients with CT-confirmed ischaemic colitis without a suspicion of colorectal cancer were eligible. Clinical data, colonoscopic findings and histopathological results were extracted from medical records. Comparative analyses were conducted between patients who underwent complete colonoscopy and those who did not.

Results: Among the 418 patients diagnosed with ischaemic colitis, 396 underwent CT imaging, and 116 underwent subsequent complete colonoscopy. Colorectal polyps were identified in 34.5% (40/116) of the patients, with 75 lesions predominantly located in the right-sided colon. Invasive colorectal carcinoma was detected in 3.4% (4/116) of the patients, along with an additional case of intramucosal carcinoma. Notably, one invasive adenocarcinoma was located proximal to the site of the ischaemic injury. Between the complete colonoscopy and incomplete/no colonoscopy groups, the patients in the incomplete/no colonoscopy group were significantly older, had a higher proportion of poor performance status and were more likely to have used saline laxatives.

Conclusion: Colonoscopy after ischaemic colitis revealed a non-negligible prevalence of colorectal neoplasms even in the absence of CT findings suggestive of malignancies. These results underscore the importance of colonoscopy after recovery, particularly in patients without a poor performance status. Further prospective, multicentre studies are warranted to validate these findings and optimise postischaemic colitis management strategies.