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In the treatment of ulcerative colitis (UC), accurate evaluation of UC activity is important to achieve mucosal healing. We sought to investigate the clinical utility of linked color imaging (LCI) for the evaluation of endoscopic activity and prediction of relapse in UC patients. We enrolled 72 consecutive UC patients in remission who underwent colonoscopy at our institution between September 2016 and October 2018. The relationship between the presence of redness in white light imaging (WLI) and LCI and histopathological inflammation (Geboes score: GS) at 238 biopsy sites was examined. We also assessed the presence or absence of planar redness in the entire rectum as ± and classified the patients into three groups according to the combination of WLI/LCI: A: WLI-/LCI-, B: WLI-/LCI+, and C: WLI+/LCI+. The relationship between WLI/LCI classification and relapse in 64 patients followed up for more than 12 months from initial colonoscopy was assessed and compared to the Mayo endoscopic subscore (MES). A GS of 0 or 1 accounted for 89% of WLI/LCI non-redness sites, while a GS of 2 or 3 accounted for 42% of WLI non-redness/LCI redness sites. LCI findings were significantly correlated with GS. During follow-up, 10 patients in group C and four patients in group B relapsed, but none in group A. Non-relapse rates were significantly correlated with WLI/LCI classification, but not with MES. LCI is a useful modality for accurate assessment of endoscopic activity and prediction of relapse in UC by detecting mild inflammation unrecognizable by WLI.

Transanal endoscopic microsurgery (TEM) is a technique that was introduced in the 1980s for improved exposure to upper rectal polyps. This technique, though initially difficult to master due to new skill acquisition for surgeons, has spared many patients proctectomy. There are many benign indications for transanal endoscopic surgery which has led to in vivo operating room training with fewer undesirable effects to the patient. With the explosion of laparoscopic technology this transanal technique is no longer limited to intraluminal pathology, but is now being used to remove the entire rectum. In transanal total mesorectal excision (taTME), benign indications are less common, translating to potentially more severe oncologic patient consequences during the early phase of adoption. For this reason, strict training criteria consensus guidelines have been developed by the experts in taTME. The current consensus statements agree that training surgeons should have performed a minimum of 10 laparoscopic TME procedures and should have some experience with transanal surgery. Surgeons need to attend a formal training course and should start clinically on benign or early malignant pathology without threated circumferential resection margins. Surgeons also need to have their first cases proctored until deemed proficient by the proctor and monitor their morbidity, oncologic, and functional outcomes prospectively.

Purpose To compare the fits of normal-tissue complication probability (NTCP) models based on rectal dose–wall histograms (DWHs) vs. dose–volume histograms (DVHs) when the two are used to analyze a common set of late rectal toxicity data. Methods and materials Data were analyzed from 128 prostate cancer patients treated with 3-dimensional conformal radiotherapy (3D-CRT) at The University of Texas M.D. Anderson Cancer Center (UTMDACC). The DVH for total rectal volume, including contents, was obtained for each patient from the treatment-planning system. A DWH was also computed, using the outer rectal contour plus an autogenerated inner contour that corresponds to an assumed 3-mm rectal wall thickness. The endpoint for analysis was Grade 2 or higher late rectal bleeding within 2 years of treatment; all patients had at least 2 years of follow-up. Four different NTCP models were fitted to the response data by using either the DVH or the DWH to describe the dose distribution to rectum or rectal wall, respectively. The 4 models considered were the Lyman model, the mean dose model, the parallel-architecture model, and a model based on the volume of a organ receiving more than a specified dose (the “cutoff-dose” model). Results For each of the models, the fit to the late rectal bleeding data was slightly improved when the analysis was based on the rectal DWH instead of on the DVH. In addition, the results of the cutoff dose and parallel architecture models were consistent with one another for the DWH data but not for the DVH data. For the DWH data, both models predict a 50% or higher incidence of Grade 2 or worse late rectal bleeding within 2 years if 80% or more of the rectal wall is exposed to doses greater than 32 Gy. A 50% or higher incidence of rectal bleeding is also predicted if the mean dose to rectal wall exceeds 53.2 Gy. Conclusions A consistent, although modest, improvement occurs in the fits of NTCP models to the UTMDACC 2-year late rectal bleeding data when the fit is based on the rectal dose–wall histogram instead of on the dose–volume histogram for entire rectum, including contents.

BACKGROUND AND PURPOSE: To develop a method to project surface elements of a bent tubular organ, e.g. the rectum, in order to create a two-dimensional (2D) map and to use this method to quantify on a local scale shape and position variations of the rectum. PATIENTS AND METHODS: For this study we used data of 19 patients, who each received a planning CT scan and 9-13 repeat CT scans that were considered representative for the radiotherapy course. We combined maps from multiple CT scans of the same patient to quantify local rectal wall displacements. To make a map we first computed a central axis through the rectum and divided it into segments of equal length assuming that the length of these segments was invariant under rectum shape and position changes. Next, we constructed for each segment a planar cross section through the rectum, which was oriented orthogonally to that segment. The amount of rectal wall tissue was assumed to be constant in all orthogonal cross sections throughout the entire rectum. We unfolded the cross-sected rectal wall at the dorsal side and projected either the associated dose or the coordinates onto the map. RESULTS: The largest variation in the position of the rectal wall during the treatment course occurred at the upper anterior, left and right side (1 SD=5-7 mm). Near the anus the variation was

Transanal endoscopic microsurgery (TEM) is a relatively new, minimally invasive technique for removing broad-based villous adenomas and “low-risk” carcinomas throughout the entire rectum. Using stereooptic and surgical proctoscopes, the tumor is accessible to both the eye and microsurgical instruments (Fig. 23.1). This method was developed more than 10 years ago by Buess et al. [4, 5], first in Cologne and later in Tubingen. It has now become widely established in Germany, England, the United States, and Switzerland [22–27].

Although there is no standard terminology for the various lesions that are grouped together under this heading, most surgeons loosely define the term “prolapse” as the protrusion of either mucous membrane or the entire muscular wall of the rectum outside the anus. To be more specific, one should use the term “mucosal prolapse” or “procidentia,” which is defined as the extrusion of the entire rectum including the muscular wall.

While villous adenomas of the rectum are common, they rarely encompass the entire rectum to the dentate line. It is even more unusual to find a tumor of this size to be benign. Fluid and electrolyte deficits associated with this tumor add to the difficulty in management. The experienced surgeon should be aware of the various modes of treatment and be able safely to use the appropriate operation. It is as grave an injustice to the patient to treat a benign lesion as a malignancy as it is to remove the rectum for a benign villous adenoma.