The 2014 commissioning guidelines of the Royal College of Surgeons and Association of Coloproctology in Great Britain and Ireland (ACPGBI) recommended routine luminal colonic screening by either endoscopy, barium enema or CT colonography following the resolution of the acute episode [5]. The latest guidelines by the American Gastroenterological Association Institute in 2015 suggest that colonoscopy should be performed after resolution of diverticulitis in appropriate candidates to exclude the misdiagnosis of a colonic neoplasm if a high-quality examination of the colon has not been recently performed [7]. The last practice parameter published by the task force of the American Society of Colon and Rectal Surgeons in 2014 recommended that a colonoscopy should be performed in 6 to 8 weeks following resolution of the acute episode [8]. However, these recommendations were based on a low quality of evidence. There is has been no evidence of a causal link between colonic diverticular disease and malignancy or IBD. This mis-association can be explicated by the fact that the diagnosis of diverticulitis in those studies was based on clinical examination and poor-quality imaging modalities such as ultrasonography, barium enemas and poorer quality CT scanners. The recent advances in the quality of MSCT scanners enhanced the accuracy of the diagnosis of diverticular disease with a high sensitivity and specificity of 99% and 95% respectively [9].
In 2015, An international Delphi study including expert colorectal surgeons advised against the practice of routine colonoscopy in all patients with uncomplicated diverticulitis. The consensus opinion was that endoscopy is advised only in selected patients [13]. The latest ACPGBI guidelines, in 2021, recommended that the routine interval colonoscopic investigations following uncomplicated diverticulitis is unnecessary. The indications for endoscopic investigations include patients who have complicated diverticulitis, the presence of suspicious colonic wall thickening on CT scan or having red flag bowel symptoms [6].
Several studies have analyzed the colon cancer detection rate in patients who underwent endoscopic investigations following acute diverticulitis. The reported incidence of colonic neoplasia varied significantly between different studies. Multiple meta-analysis and systematic reviews reported the rate of associated colonic malignancy between 0.25% and 0.78% in uncomplicated diverticulitis and 7.8–10.9% in complicated diverticulitis [14–23].
Our study is the largest single study investigating the yield of endoscopic investigations following acute diverticulitis. Our data shows that the incidence of colorectal cancer (CRC) or advanced adenomas (AA) in patients with uncomplicated (Hinchey 1A) diverticulitis is only 0.14%. The incidence of CRC/AA in patients with Hinchey 1b and Hinchey 2 is 1.4% and 4.4% respectively. Interestingly, 50% of diagnosed malignant lesions were detected in the non-disease colon. 18/98 patients (18.4%) out of the patients who underwent emergency colonic resection for suspected perforated diverticulitis had a diagnosis of colonic cancer with or without diverticulitis.
Amongst all cases that had an endoscopic procedure post diverticulitis, 11 patients (1.5%) were re-admitted with complications secondary to colonoscopy. This puts into question the need for an endoscopy procedure post diverticulitis, with its attendant risks and additional costs related to procedures that may not add to optimal patient care.
In conclusion, there is a lack of robust evidence regarding causal correlation between diverticulitis and CRC. Multiple recent studies including our study suggest that the cohort of patients who have a MSCT proven uncomplicated diverticulitis may have a risk of underlying or associated CRC or AA which is equivalent or less than the normal population risk. Therefore, those patients should follow the national bowel cancer screening pathway with no need for additional endoscopic investigations. Colonoscopy should be reserved to those patients who had complicated diverticulitis; Hinchey stage 1b or beyond and patients with uncomplicated diverticulitis who have high risk features and patients whose CT scan showed a suspicion of underlying mass lesion, in line with the latest ACPGBI consensus guidelines. We recommend that patients who are referred for endoscopic investigations should have a full colonoscopy, if possible, to rule out malignant lesions in the non-diseased colon. Surgeons should aim to perform an oncological colonic resection for perforated diverticulitis, when technically feasible, as the risk of concomitant malignancy is relatively high.