Transanal Total Mesorectal Excision (TaTME) has recently been developed to overcome the difficulties associated with conventional laparoscopic or robotic TME. TaTME has gained popularity and becomes the center of attention among colorectal surgeons globally. The present review aims to update the literature, clarify the current status and perspectives of TaTME. Complete TaTME specimens were obtained in 85-97.1% of the case; the reported circumferential resection margin (CRM) ranged from 1.5% to 8.1%, whereas and distal resection margin (DRM) positive rates ranged from 0% to 3.2%. The conversion rate of TaTME occurred from 0 to 15%, and there was no difference between TaTME and laparoscopic or robotic TME. Intraoperative complications occurred in 5-6% of the case, which compared favorably to laparoscopic TME. The most serious intraoperative complication with this approach was urethral injury, although only small numbers were reported, which was possibly due to under-reporting. Clavien-Dindo I or II postoperative complications occurred in 22-24% of the case, and III or IV in 10-11% of the case, which did not differ between TaTME and laparoscopic or robotic TME. TaTME may be technically easier and more beneficial than laparoscopic, robotic or open TME in male patients with a narrow pelvis; in obese patients with a bulky tumor. At present two randomized controlled trials, COLOR III and GRECCAR, and comparing TaTME with laparoscopic TME are being conducted and their outcomes are awaited. TaTME is a complex procedure, but proved to be feasible, oncologically safe, and effective in difficult cases. Before this new technique is adopted, proper training with Proctor/mentorship is strongly advised. Careful case selection and audit of data are mandatory.

Objectives: We determined the outcomes of seton treatment through a series of techniques using biological agents (BIOs) in 18 patients with Crohn's disease (CD) who initially presented with perianal fistulas. Methods: The patients underwent seton drainage using three seton types: a Penrose tube for fistulas with massive purulent discharge, a vessel loop for a small amount of discharge, and a rubber band for unproductive fistulas. If the distal end of the fistula extended more than 4 cm from the anal orifice, the skin and subcutaneous tissue were dissected along the outer edge of the anal sphincter to divide the fistulous tract into two portions. One seton encircled the sphincter from the primary opening throughout the anal canal (medial seton), and the other was inserted through the distal tract outside the sphincter (lateral seton). A BIO was then introduced immediately. When discharge ceased, the Penrose tube or vessel loop was replaced sequentially with a rubber band, which was tied fittingly and subsequently removed in medial to lateral order. Results: The mean interval between fistula onset and CD diagnosis was 2.1 years, and that between CD diagnosis and introduction of BIOs was 0.5 years. The mean follow-up duration was 4 years. The BIOs currently used were infliximab in 10 patients, adalimumab in 7, and ustekinumab in 1. The overall success rate was 94.4%, including unproductive fistulas in 10 (55.6%) patients and fistula disappearance in 7 (38.9%). Conclusions: Our seton drainage techniques via the "top-down" approach represent a promising avenue for treating perianal fistulas in patients with CD.

Objectives: The aim of this study was to use magnetic resonance imaging (MRI) to elucidate the site and depth of the primary abscesses associated with deep posterior anal fistulas and their extension patterns. Methods: We analyzed 176 consecutive patients with deep posterior anal fistulas and classified the fistulas according to whether the MRI-detected site of the primary abscess was at a superficial or a deep external anal sphincter (EAS) level. Results: The distance between the anal center and the primary abscess center was significantly shorter than the length of the EAS and radius at an angle of 45°. In addition, deep posterior anal fistulas with primary abscesses located at the deep EAS level penetrated the EAS significantly more laterally and made external openings at a significantly more lateral site than when the primary abscess was located at a superficial EAS level. Conclusions: Primary abscesses associated with deep posterior anal fistulas are located in the posterior intersphincteric space or in the EAS muscle itself, not in Courtney's space, as had previously been claimed.

Objectives: Although various pelvic floor abnormalities are recognized to cause mucus discharge (MD), little is known about the exact distribution and frequency of diseases causing MD in evacuatory disorders. This study aimed to identify the most common diseases at evacuation proctography in patients with MD. Methods: Patients seen with symptoms of evacuatory disorder underwent proctography. Data for patients with MD who were not associated with fecal incontinence (FI) were prospectively entered into a database and analyzed retrospectively. The degree of MD was documented using FI Severity Index. Results: Sixty-two patients were included for analysis. Forty-nine (79%) had rectal intussusception (RI) or external rectal prolapse (ERP). Of those with RI, MD was observed more in patients with recto-anal intussusception (n = 22) than those with recto-rectal intussusception (n = 8). Of the 39 patients who were not associated with hemorrhoids or mucosal prolapse, 31 (79%) had RI or ERP. Meanwhile, of 582 patients who underwent proctography, 301 had RI and 96 had ERP. MD without FI was present in 13% (40/301) patients with RI and 9% (9/96) with ERP. Surgery was performed in 21 patients, and MD was cured in 20 (95%) postoperatively. Conclusions: RI and ERP were common at proctography in patients with MD.

Objectives: One of the characteristics of colorectal cancer complicating Crohn's disease (CD) in the Japanese population is that it frequently occurs in the lower anorectal site. This study aimed to examine CD patients biopsied in the lower anorectal sites to investigate the significance and problems associated with this method of cancer surveillance. Methods: Among 116 patients with CD duration of ≥10 years, we examined patients diagnosed with cancer using histological examination of the lower anorectal site (287 times). We also evaluated the detection rates of cancer and atypical cells using this method.Results: Of the 116 patients, neoplastic lesions were detected through biopsy in 22 (19.0%), of which 18 had carcinomas and 4 had atypical cells. The clinicopathological traits of the cancer patients were early-age onset and chronic disease duration of CD before cancer diagnosis. Histologic findings were characterized by a high frequency of poorly differentiated adenocarcinoma and mucinous carcinoma. The 18 patients with cancer were assigned to groups A and B depending on the presence or absence of cancer-related symptoms, and their characteristics were compared. Of these, 5 patients whose cancer was detected without symptoms (group A) had better prognosis than those detected with symptoms (group B) based on survival curves. We next examined 103 patients for surveillance after excluding 13 patients who were diagnosed with cancer-related symptoms from the 116 patients and found a 5.8% (6 patients) detection rate of cancer and atypical cells.Conclusions: Our results suggest the effectiveness of transanal histological testing for the surveillance of anorectal cancer with CD.

Objectives: Colonoscopy is the first-line modality to examine the colon even in the very elderly but may have an increased risk of complications. This study aimed to evaluate the efficacy and safety of colonoscopy in the very elderly. Methods: Patients ≥85y old, who underwent colonoscopy between September 2010 and August 2012 in two tertiary-care hospitals in Japan were enrolled. Main outcome measures were cecal intubation rate, detection rate of adenomas and cancers, treatment, adverse events, and long-term outcomes. Results: A total of 207 colonoscopies were performed in 177 patients (females 72, males 105; maximum age 95 years). Of these, 202 attempted to reach the cecum, with success in 92%. Excluding patients with known colorectal neoplasms, invasive cancers were detected in 12%, including T1 lesions in 2% and T2 or deeper in 9%. No cancers were detected in patients referred for surveillance or mild abdominal symptoms. Cancers were found in 25% of patients with positive fecal immunochemical tests, 22% with altered bowel habits, 21% with anemia, and 18% with hematochezia. Treatment of 29 patients with cancer included surgery in 22, endoscopic resection in two and no treatment (due to comorbidities) in five. There were no complications. During 730 days (mean) of follow up, 27 patients died but only three died from recurrent colorectal cancer. Conclusions: Colonoscopy for patients aged ≥85 years is safe. A relatively high detection rate of cancers was found, and most were treatable and even curable. (UMIN000018575)

Objectives: Fecal incontinence (FI) is a multifactorial disorder, the etiology of which is not fully understood. Recent data have shown the significance of rectoanal intussusception (RAI) in the evaluation of FI. The present study aimed to determine the incidence of RAI in patients with FI. Methods: Between June 2010 and February 2016, 74 patients, who were evaluated using evacuation proctography, anorectal manometry, ultrasound, and incontinence scores, were included in this study. RAI was diagnosed when the apex of the rectal intussusception (RI) impinged on the internal anal orifice or was intra-anal, based on the images taken during maximal straining defecation at evacuation proctography. The characteristics of RAI patients were further analyzed. Results: There were 59 women (80%) and 15 men, with a median age of 74 (52-93) years. Sixty patients (81%) had RI, and 56 (76%) showed RAI. The incidence of RAI among the 32 patients with FI alone and the 42 patients with FI and symptoms of obstructed defecation (OD) was 72% (23/32) and 79% (33/42), respectively. The incidence of RAI was not significantly different between the patients with normal manometry (maximum resting pressure [MRP] ≥55 cmH₂O and maximum squeeze pressure [MSP] ≥150 cmH₂O, n=26) and those with subnormal manometry (MRP <55 cmH₂O and/or MSP <150 cmH₂O, n=48). Conclusion: RAI is common in patients with FI. Evacuation proctography should be taken into account as a part of the regular study of FI patients.

Objectives: This study aimed to evaluate the long-term outcomes of neoadjuvant chemoradiotherapy with S-1 in patients with locally advanced rectal cancer. Methods: A multi-institutional, prospective, phase II trial was conducted between April 2009 and August 2011. The study enrolled 37 patients with histologically proven rectal carcinoma (T3-4 N0-3 M0) who underwent neoadjuvant chemoradiotherapy with S-1. Total mesorectal excision with D3 lymphadenectomy was performed 4-8 weeks after completion of neoadjuvant chemoradiotherapy with S-1 in 36 patients. We then analyzed late adverse events, overall survival, and disease-free survival. Results: The median patient age was 59 years (range: 32-79 years); there were 24 men and 13 women. Ten patients had Stage II disease, and 27 had Stage III disease. Severe late adverse events occurred in 7 patients (18.9%). The 5-year disease-free survival was 66.7%, and the 5-year overall survival was 74.7%. The median follow-up period was 57 months. Local recurrences developed in 5 patients (13.5%), and distant metastases developed in 8 (21.6%). Conclusion: Neoadjuvant-synchronous chemoradiotherapy with S-1 for locally advanced rectal cancer is feasible in terms of adverse events and long-term outcomes. (UMIN Clinical Trial Registry: UMIN000003396)