BACKGROUND AND AIMS Controversy surrounds the risk of colorectal cancer (CRC) in ulcerative colitis (UC). Many studies have investigated this risk and reported widely varying rates. METHODS A literature search using Medline with the explosion of references identified 194 studies. Of these, 116 met our inclusion criteria from which the number of patients and cancers detected could be extracted. Overall pooled estimates, with 95% confidence intervals (CI), of cancer prevalence and incidence were obtained using a random effects model on either the log odds or log incidence scale, as appropriate. RESULTS The overall prevalence of CRC in any UC patient, based on 116 studies, was estimated to be 3.7% (95% CI 3.2–4.2%). Of the 116 studies, 41 reported colitis duration. From these the overall incidence rate was 3/1000 person years duration (pyd), (95% CI 2/1000 to 4/1000). The overall incidence rate for any child was 6/1000 pyd (95% CI 3/1000 to 13/1000). Of the 41 studies, 19 reported results stratified into 10 year intervals of disease duration. For the first 10 years the incidence rate was 2/1000 pyd (95% CI 1/1000 to 2/1000), for the second decade the incidence rate was estimated to be 7/1000 pyd (95% CI 4/1000 to 12/1000), and in the third decade the incidence rate was 12/1000 pyd (95% CI 7/1000 to 19/1000). These incidence rates corresponded to cumulative probabilities of 2% by 10 years, 8% by 20 years, and 18% by 30 years. The worldwide cancer incidence rates varied geographically, being 5/1000 pyd in the USA, 4/1000 pyd in the UK, and 2/1000 pyd in Scandinavia and other countries. Over time the cancer risk has increased since 1955 but this finding was not significant (p=0.8). CONCLUSIONS Using new meta-analysis techniques we determined the risk of CRC in UC by decade of disease and defined the risk in pancolitics and children. We found a non-significant increase in risk over time and estimated how risk varies with geography.

https://gut.bmj.com/content/gutjnl/48/4/526.full.pdf

The risk of colorectal cancer in ulcerative colitis: a meta-analysis

http://www.klinikcity.ru/wp-content/uploads/2012/03/Guidelines/Gastroenterology/Ulceral_Colitis_ACG_2010.pdf

Ulcerative colitis practice guidelines in adults: American College Of Gastroenterology, Practice Parameters Committee.

Background The risk of colorectal cancer is increased among patients with ulcerative colitis. The magnitude of this increase in risk and the effects of the length of follow-up, the extent of disease at diagnosis, and age at diagnosis vary substantially in different studies. Methods To provide accurate estimates of the risk of colorectal cancer among patients with ulcerative colitis, we studied a population-based cohort of 3117 patients given a diagnosis of ulcerative colitis from 1922 through 1983 who were followed up through 1984. Results Ninety-two cases of colorectal cancer occurred in 91 patients. As compared with the expected incidence, the incidence of colorectal cancer in the cohort was increased (standardized incidence ratio [ratio of observed to expected cases] = 5.7; 95 percent confidence interval, 4.6 to 7.0). Less extensive disease at diagnosis was associated with a lower risk; for patients with ulcerative proctitis, the standardized incidence ratio was 1.7 (95 percent confidence interval, 0.8 to 3.2); for those with left-sided colitis, 2.8 (95 percent confidence interval, 1.6 to 4.4); and for those with pancolitis (extensive colitis, or inflammation of the entire colon), 14.8 (95 percent confidence interval, 11.4 to 18.9). Age at diagnosis and the extent of disease at diagnosis were strong and independent risk factors for colorectal cancer. For each increase in age group at diagnosis (less than 15 years, 15 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, and greater than or equal to 60 years), the relative risk of colorectal cancer, adjusted for the extent of disease at diagnosis, decreased by about half (adjusted standardized incidence ratio = 0.51; 95 percent confidence interval, 0.46 to 0.56). The absolute risk of colorectal cancer 35 years after diagnosis was 30 percent for patients with pancolitis at diagnosis and 40 percent for those given this diagnosis at less than 15 years of age. Conclusions Close surveillance and perhaps even prophylactic proctocolectomy should be recommended for patients given a diagnosis of pancolitis, especially those who are less than 15 years of age at diagnosis.

https://www.nejm.org/doi/pdf/10.1056/NEJM199011013231802

Ulcerative colitis and colorectal cancer. A population-based study.

The British Society of Gastroenterology (BSG) and the Association of Coloproctology for Great Britain and Ireland (ACPGBI) commissioned this update of the 2002 guidance. The aim, as before, is to provide guidance on the appropriateness, method and frequency of screening for people at moderate and high risk from colorectal cancer. This guidance provides some new recommendations for those with inflammatory bowel disease and for those at moderate risk resulting from a family history of colorectal cancer. In other areas guidance is relatively unchanged, but the recent literature was reviewed and is included where appropriate.

https://gut.bmj.com/content/gutjnl/59/5/666.full.pdf

Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002)

https://www.spg.pt/wp-content/uploads/2015/11/2013-JCC_ECCO_Endoscopy_Consensus_10_2013_inPress.pdf

European evidence based consensus for endoscopy in inflammatory bowel disease

Cancer in universal and left-sided ulcerative colitis: factors determining risk.

The incidence of bowel cancer was studied in 132 patients who had undergone bypass surgery for Crohn's disease and who had been admitted to The Mount Sinai Hospital between 1960 and 1976. Seven patients (5.3 per cent) developed cancer (4 of 63 with ileocolitis and 3 of 69 with ileitis). All seven cancers appeared in excluded loops, four in small bowel and three in colon. Six of the cancers occurred at sites of previous active inflammatory disease and one in a relatively normal “skipped” area of cecum. Four were associated with fistulas: two with enterovesical; one with enterocutaneous; and one with both. In only one case was a tumor mass palpable. All seven patients in this series underwent operation and all showed metastatic spread to liver, lymph nodes, or adjacent organs. All patients died within two years of the diagnostic laparotomy. The mean latent period between onset of disease and appearance of cancer was twenty-seven years, and between bypass surgery and appearance of cancer thirteen years. Four of the seven cancers occurred relatively early, within four years of the bypass procedure, but all seven cases had one feature in common—a long duration of Crohn's disease prior to the development of cancer, ranging from seventeen to forty-four years. The diagnosis of cancer in excluded bowel was difficult to make and impossible to confirm prior to laparotomy. Among the large bowel cancers, a preoperative diagnosis was established, by sigmoidoscopy, in only one case. Cancer in a bypassed loop should be suspected in any case of Crohn's disease of long duration when a late recrudescence of symptoms occurs, especially when the symptoms are associated with the new appearance of fistula or mass.

A. Pucillo

Papers

Cancer in universal and left-sided ulcerative colitis: factors determining risk.

Cancer in Crohn's disease after diversionary surgery: A report of seven carcinomas occurring in excluded bowel

Cancer in universal and left-sided ulcerative colitis: clinical and pathologic features.