Integrating artificial intelligence (AI) applications into colonoscopy practice is being accelerated as deep learning technologies emerge. In this field, most of the preceding research has focused on polyp detection and characterization, which can mitigate inherent human errors accompanying colonoscopy procedures. On the other hand, more challenging research areas are currently capturing attention: the automated prediction of invasive cancers. Colorectal cancers (CRCs) harbor potential lymph node metastasis when they invade deeply into submucosal layers, which should be resected surgically rather than endoscopically. However, pretreatment discrimination of deeply invasive submucosal CRCs is considered difficult, according to previous prospective studies (e.g., <70% sensitivity), leading to an increased number of unnecessary surgeries for large adenomas or slightly invasive submucosal CRCs. AI is now expected to overcome this challenging hurdle because it is considered to provide better performance in predicting invasive cancer than non-expert endoscopists. In this review, we introduce five relevant publications in this area. Unfortunately, progress in this research area is in a very preliminary phase, compared to that of automated polyp detection and characterization, because of the lack of number of invasive CRCs used for machine learning. However, this issue will be overcome with more target images and cases. The research field of AI for invasive CRCs is just starting but could be a game changer of patient care in the near future, given rapidly growing technologies, and research will gradually increase.

Objectives: Ligation and excision remain the commonly recognized standard surgical modality for treating hemorrhoids. Further, impediments to surgical treatment owing to social factors and the need for minimally invasive procedures and other confounders have resulted in the adoption of the mucopexy-recto anal lifting (MuRAL) method which is associated with favorable outcomes. The objective of this study was to describe the procedure and report the outcomes in patients who underwent MuRAL.

Methods: Between March 2016 and February 2018, 55 patients (26 males and 29 females) underwent MuRAL for hemorrhoids and rectal mucosal prolapse. The duration of the surgical procedure and hospitalization, postoperative complications, and satisfaction were evaluated.

Results: The mean age of the male patients (n = 26) was 61.5 ± 4.9 years and that of the female patients (n = 29) was 61.5 ± 3.2 years. The mean duration of surgery was 46 ± 23 minutes for males and 53 ± 28 minutes for females, and the mean observation duration was 317 ± 186 days. Intraoperative hemorrhage was low for males and females. The mean hospitalization period was 3.2 ± 1.5 days for males and 4.3 ± 2.1 days for females. Differences in several postoperative complications were observed between male and female patients. Postoperative satisfaction was rated high by the patients.

Conclusions: Risks of hemorrhage and pain associated with the MuRAL method were low because the procedure does not involve incision or excision. Other than ligation and excision, recurrence is favorable compared with that of other surgical modalities for the treatment of hemorrhoids.

Objectives: The necessary and sufficient length of the distal resection margin (l-DRM) for rectosigmoid cancer remains controversial. This study evaluated the validity of the 3-cm l-DRM rule for rectosigmoid cancer in the Japanese classification of colorectal cancer.

Methods: We retrospectively reviewed 1,443 patients with cT3 and cT4 rectosigmoid cancer who underwent R0 resection in Japanese institutions between 1995 and 2004. We identified the optimal cutoff point of the l-DRM affecting overall survival (OS) rate using a multivariate Cox regression analysis model. Using this cutoff point, the patients were divided into two groups after balancing the potential confounding factors of the l-DRM using propensity score matching, and the OS rates of the two groups were compared.

Results: A multivariate Cox regression analysis model revealed that the l-DRM of 4 cm was the best cutoff point with the greatest impact on OS rate (hazard ratio [HR], 1.37; 95% confidence interval [CI], 1.00-1.84; P = 0.0452) and with the lowest Akaike information criterion value. In the matched cohort study, the OS rate of patients who had l-DRM of 4 cm or more was significantly higher than that of patients who had l-DRM < 4 cm (n = 402; 5-year OS rates, 87.6% vs. 80.3%, respectively; HR, 1.60; 95% CI, 1.09-2.31; P = 0.0136).

Conclusions: For cT3 and cT4 rectosigmoid cancer, l-DRM of 4 cm may be an appropriate landmark for a curative intent surgery, and we were unable to definitively confirm the validity of the Japanese 3-cm l-DRM rule.

Objectives: Cold polypectomy (CP) is widely used because of its safety profile. This systematic review and meta-analysis aimed to clarify the indications for CP based on polyp size.

Methods: We searched PubMed and the Cochrane Library for randomized controlled trials that compared cold snare polypectomy (CSP) and other procedures for polyps ≤10 mm. Large-scale prospective observational studies were also searched to assess delayed bleeding rates. The studies were integrated to assess the risk ratio for incomplete resection rates according to polyp size. The Cochrane risk of bias tool was used to evaluate the study bias. The certainty of cumulative evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation system.

Results: We found 280 articles and reviewed their eligibility. We selected and extracted 12 randomized controlled trials and 3 prospective observational studies. The risk ratio of incomplete resection of polyps ≤10 mm using CSP compared with hot snare polypectomy (HSP) was 1.36 (95% confidence interval [CI], 0.92-2.01). The risk ratio for incomplete removal using CSP compared with cold forceps polypectomy (CFP) was 0.50 (95% CI, 0.31-0.82). For polyps ≤3 mm, the risk ratio of CSP compared with CFP was 1.40 (95% CI, 0.39-4.95). Certainty of cumulative evidence was considered low. No delayed bleeding after CP was reported after the treatment of 3446 polyps.

Conclusions: CSP and HSP may result in the same complete resection rates for polyps ≤10 mm. For polyps ≤3 mm, CFP and CSP may have the same resection rates (PROSPERO registration number: CRD42019122132).

Objectives: In recent years, CapeOX therapy for patients with colorectal cancer is widely used. We previously reported that a multidisciplinary approach decreases the worsening of adverse events and increases patient satisfaction. In this study, we conducted a multicenter, prospective, observational study to evaluate the incidence of adverse events, health-related quality of life (HRQOL) of the patient, and efficacy of a management (intervention) according to the support system (SMILE study).

Methods: As the interventional method, the following more than one method was carried out in each institute, 1: support with telephone, 2: dosing instruction by a pharmacist, 3: skin care instruction by a nurse, and 4: patient instruction by a doctor. The primary endpoint was the incidence of hand-foot syndrome (HFS) of more than grade 2. The secondary endpoint was the HRQOL evaluation and efficacy. The questionnaire (HADS) was administered before the start of the chemotherapy and in 1, 2, 4, 5, and 8 courses to evaluate quality of life (QOL).

Results: From April 2011 to September 2012, 80 patients were enrolled from 14 sites, and all patients were the subjects of analysis. The demographic background was as follows: man/woman: 46/34, age median: 63 (36-75), and management interventional method 1/2/3/4: 36/68/73/78. The overall percentage of HFS that exceeded grade 2 within 6 months was 16.3%. It was 11.1% with the telephone support group and 20.5% without the telephone support group (p = 0.26).

Conclusions: A multi-professional telephone support may reduce the deterioration of HFS. Further study which includes larger cohort is needed in the future.

A 60 year-old male was referred to the authors' hospital with a persistent urge to defecate. The patient had undergone stapled hemorrhoidopexy (SH) for the treatment of prolapsed hemorrhoids approximately 10 years earlier. He started to have difficulty with defecation and a false sense of urgency shortly after the surgery. Computed tomography showed a diverticulum-like fistula along the circumference of the rectum. Colonoscopy revealed communication between the diverticular cavity and the rectal lumen. The cavity contained a thumbnail-sized fecalith. When the fecalith was removed, the patient's urge to defecate dissipated. The patient was diagnosed with rectal pocket syndrome secondary to SH. The lower rectum was transected, and the remaining rectum and the anal canal were anastomosed by manual suture. Temporary ileostomy with double orifices was performed. The ileostomy was closed 3 months later. The patient experienced no subsequent difficulty with defecation or urgency.