Background and Aim Although surveillance colonoscopy is recommended by several guidelines for Crohn's disease (CD), the evidence is insufficient to support the validity of this recommendation. Moreover, the efficacy of surveillance colonoscopy for anorectal cancer remains unclear. Therefore, we performed a systematic review of cancer in patients with CD before considering the proper surveillance methods. Methods We conducted a systematic review and meta‐analysis examining the incidence of intestinal cancer and a literature review to clarify the characteristic features of cancer in CD. We performed the systematic literature review of studies published up to May 2019. Results Overall, 7344 patients were included in eight studies. The standardized incidence ratios (95% confidence intervals) of colorectal cancer (CRC) and small bowel cancer (SBC) were 2.08 (1.43–3.02) and 22.01 (9.10–53.25), respectively. The prevalence of CRC and SBC was 57/7344 (0.77%) and 17/7344 (0.23%), respectively, during a median follow‐up of 12.55 years. Additionally, 54 studies reporting 208 anorectal cancer cases were identified. In patients with anorectal cancer, the prognosis for survival was 2.1 ± 2.3 years, and advanced cancer greater than stage T3 occurred in 46/74 patients (62.1%). Many more reports of anorectal cancer were published in Asia than in Western countries. Conclusion Although we were unable to state a recommendation for surveillance for SBC, we should perform cancer surveillance for CRC in patients with CD. However, the characteristics of cancer may differ according to geography or race. We must establish proper and effective surveillance methods that are independently suitable to detect these differences.

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T cells differentiate into highly diverse subsets and display plasticity depending on the environment. Although lymphocytes are key mediators of inflammation, functional specialization of T cells in inflammatory bowel disease (IBD) has not been effectively described. Here, we performed deep profiling of T cells in the intestinal mucosa of IBD and identified a CD4 + tissue-resident memory T cell (Trm) subset that is increased in Crohn’s disease (CD) showing unique inflammatory properties. Functionally and transcriptionally distinct CD4 + Trm subsets are observed in the inflamed gut mucosa, among which a CD-specific CD4 + Trm subset, expressing CD161 and CCR5 along with CD103, displays previously unrecognized pleiotropic signatures of innate and effector activities. These inflammatory features are further enhanced by their spatial proximity to gut epithelial cells. Furthermore, the CD-specific CD4 + Trm subset is the most predominant producer of type 1 inflammatory cytokines upon various stimulations among all CD4 + T cells, suggesting that the accumulation of this T cell subset is a pathological hallmark of CD. Our results provide comprehensive insights into the pathogenesis of IBD, paving the way for decoding of the molecular mechanisms underlying this disease.

Background and Aims Performing a mucosectomy with a hand-sewn ileal pouch-anal anastomosis [IPAA] for ulcerative colitis [UC] theoretically reduces the risk of carcinoma arising from the anal transitional zone [ATZ]. Although current guidelines suggest a stapled anastomosis due to the low incidence of cancer after pouch surgery in UC patients, only a few small series have addressed the oncological advantage of mucosectomy. Therefore, we aimed to investigate the incidence of ATZ/pouch cancer. Methods A total of 1970 UC patients who underwent surgery between April 1987 and December 2018 were included. We retrospectively analysed the incidences of primary ATZ cancer in the original operative specimen and de novo ATZ/pouch cancer after surgery. Possible risk factors for primary ATZ cancer and the pouch survival rate were assessed. Results Fourteen [6.4%] primary ATZ cancers developed in 220 UC-colorectal cancer [CRC] cases. Multiple (odds ratio [OR] = 8.79, 95% confidence interval [CI] 2.77–27.83, p < 0.01) and rectal [OR = 6.48, 95% CI 1.41–29.7, p = 0.01] cancers were identified as independent risk factors for primary ATZ cancer. Four of 1970 [0.2%] patients developed de novo ATZ/pouch cancer and dysplasia. The 10-year estimated cumulative pouch survival rate was not significantly different between stapled IPAA and hand-sewn IPAA cases [95.9% and 97.3%, p = 0.25]. Conclusion The risk of de novo ATZ/pouch cancer and dysplasia was rare. The decision to perform a hand-sewn or a stapled IAA should be made on a case-by-case basis. However, the relatively high incidence of primary ATZ cancer in UC patients with CRC suggests that mucosectomy should be recommended for this patient group.

Background/Aim: Ileal pouch anal anastomosis (IPAA) has become the surgical procedure of choice for patients with ulcerative colitis (UC). However, to date few studies have examined functional outcomes or quality of life (QOL) in elderly patients after pouch construction. Methods: In December 2017, we sent questionnaires to 224 patients aged 65 years and older at the time who underwent an IPAA at our hospital between June 1987 and May 2015 regarding issues related to QOL and functional outcomes. Responders aged 65-69 years old were defined as the elderly group (EG), while those 70 years old and over comprised the super-EG (SEG). Results: The response rate was 60.7% (136/224); 70 patients were classified as EG, and 66 were classified as SEG. The SEG were older at the time of the IPAA and during the follow-up period (p < 0.01). The stool frequency per day was 8 times in both groups (p = 0.21). There was no significant difference between the EG and SEG with regard to daytime (53 vs. 56%, p = 0.73) or nighttime (65.7 vs. 53%, p = 0.16) soiling. There was also no difference in the exacerbation of daytime or nighttime soiling compared to the first year after the operation (daytime 5.7 vs. 12.1%, p = 0.23; nighttime 7.1 vs. 9.1%, p = 0.76). QOL was evaluated using the modified fecal incontinence QOL (mFIQL) scale, with no significant difference between the EG and SEG (27 vs. 31 points). Since both groups had mFIQL scores < 50, QOL was considered to be maintained. Conclusion: In our analysis of elderly patients in the long-term period following surgery for UC, some noted fecal soiling, though QOL was largely maintained, and there were no serious effects on daily life.