Background: Transanal total mesorectal excision (taTME) facilitates sphincter preservation in low rectal cancer. Preliminary results and functional outcomes from the North American multicenter phase II taTME trial (NCT03144765) have been published. Three-year outcomes are reported. Methods: Patients with stage I to III rectal adenocarcinoma were enrolled across 11 centers (2017–2022). Endpoints included TME grade, 3-year overall survival, disease-free survival, cancer-specific survival, recurrence, late (beyond 90 d) complications, and stoma-free survival. Surveillance followed National Comprehensive Cancer Network guidelines, with pelvic magnetic resonance imaging (MRI) at 3 years to assess for pelvic sidewall recurrence when possible. Kaplan–Meier analysis assessed oncologic outcomes. Results: One hundred patients underwent taTME for tumors at a median of 5.8 cm from the anal verge, with intersphincteric resection in 36% and handsewn anastomosis in 54%. Median follow-up was 50.9 months. Late complications occurred in 32 patients, including 21 severe (Clavien-Dindo ≥3). Late anastomotic complications occurred in 5 patients; one required surgical revision. Estimated 3-year overall survival, cancer-specific survival, and disease-free survival were 93.7%, 96.6%, and 84.6%, respectively. Distant recurrence occurred in 15 patients (median: 17.6 months), most commonly in the lung and liver. Locoregional recurrence occurred in 2 patients. Preoperative N stage, lymph node yield, tumor deposits, and perineural invasion were associated with recurrence. Among 100 patients diverted at taTME, 97% were stoma-free at 3 years; 4 patients later underwent secondary diversion. Conclusions: Three-year outcomes of this multicenter trial support the safety and efficacy of taTME in resectable mid and low rectal tumors, with outcomes comparable to contemporary studies. Longer-term oncologic and functional outcomes are needed.
Functional Outcomes After Transanal Total Mesorectal Excision (taTME) for Rectal Cancer
Objective: To investigate fecal incontinence and defecatory, urinary, and sexual functional outcomes after transanal total mesorectal excision (taTME). Background: Proctectomy for rectal cancer may result in alterations in defecatory, urinary, and sexual function that persist beyond 12 months. The recent multicenter phase II taTME trial demonstrated the safety of taTME in patients with stage I to III tumors. Methods: Prospectively registered self-reported questionnaires were collected from 100 taTME patients. Fecal continence [Fecal Incontinence Quality of Life (FIQL), Wexner], defecatory function [Colorectal Functional Outcome (COREFO)], urinary function (International Prostate Symptom Score), and sexual function (Female Sexual Function Index-female, International Index of Erectile Function-male) were assessed preoperatively (PQ), 3 to 4 months postileostomy closure (FQ1), and 12 to 18 months post-taTME [postoperative questionnaire 2 (FQ2)]. Results: Among 83 patients who responded at all 3 time points, FIQL, Wexner, and COREFO significantly worsened postileostomy closure. Between FQ1 and FQ2, FIQL lifestyle and coping, Wexner, and COREFO incontinence, social impact, frequency, and need for medication significantly improved, while FIQL depression and embarrassment did not change. International Prostate Symptom Score did not change relative to preoperative scores. For females, Female Sexual Function Index declined for desire, orgasm, and satisfaction between PQ and FQ1, and did not improve between FQ1 and FQ2. In males, International Index of Erectile Function declined with no change between FQ1 and FQ2. Conclusions: Although taTME resulted in initial decline in defecatory function and fecal continence, most functional domains improved by 12 months after ileostomy closure, without returning to preoperative status. Urinary function was preserved while sexual function declined without improvement by 18 months post-taTME. Our results address patient expectations and inform shared decision-making regarding taTME.
Discordance in Total Mesorectal Excision Specimen Grading in a Prospective Phase 2 Multicenter Rectal Cancer Trial
Objectives: To report the results of a rigorous quality control (QC) process in the grading of total mesorectal excision (TME) specimens during a multicenter prospective phase 2 trial of transanal TME. Background: Grading of TME specimens is based on the macroscopic assessment of the mesorectum and standardized through synoptic pathology reporting. TME grade is a strong predictor of outcomes with incomplete (IC) TME associated with increased rates of local recurrence relative to complete or near complete (NC) TME. Although TME grade serves as an endpoint in most rectal cancer trials, in protocols incorporating centralized review of TME specimens for quality assurance, discordance in grading and the management thereof has not been previously described. Methods: A phase 2 prospective transanal TME trial was conducted from 2017 to 2022 across 11 North American centers with TME quality as the primary study endpoint. QC measures included (1) training of site pathologists in TME protocols, (2) blinded grading of de-identified TME specimen photographs by central pathologists, and (3) reconciliation of major discordance before trial reporting. Cohen Kappa statistic was used to assess agreement in grading. Results: Overall agreement in grading of 100 TME specimens between site and central reviewer was rated as fair, (κ = 0.35; 95% CI: 0.10–0.61; P < 0.0001). Concordance was noted in 54%, with minor and major discordance in 32% and 14% of cases, respectively. Upon reconciliation, 13/14 (93%) major discordances were resolved. Pre versus postreconciliation rates of complete or NC and IC TME are 77%/16% and 7% versus 69%/21% and 10%. Reconciliation resulted in a major upgrade (IC–NC; N = 1) or major downgrade (NC/C–IC, N = 4) in 5 cases overall (5%). Conclusions: A 14% rate of major discordance was observed in TME grading between the site and central reviewers. The resolution resulted in a major change in final TME grade in 5% of cases, which suggests that reported rates or TME completeness are likely overestimated in trials. QC through a central review of TME photographs and reconciliation of major discordances is strongly recommended.
Genetic coding variant in complement factor B (CFB) is associated with increased risk for perianal Crohn’s disease and leads to impaired CFB cleavage and phagocytosis
Objective Perianal Crohn’s disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP in Complement Factor B ( CFB ). Design Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum from CFB risk, or protective CD or healthy subjects was assessed by flow cytometry. Results Perianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) in CFB , in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum. Conclusion pCD-associated rs4151651 in CFB is a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.
P107 Evolution of Imaging in the Preoperative Assessment of Patients Undergoing Ileal Pouch Surgery
BACKGROUND: Ileal pouch-anal anastomosis (IPAA) is the standard operative approach for ulcerative colitis (UC) or inflammatory bowel disease unclassified (IBDu) patients with medical refractory disease or dysplasia. Pouchitis or denovo Crohn’s disease are frequent adverse outcomes. The presence of small bowel (SB) mucosal inflammation before surgery might be an important predictor of these outcomes after surgery. Although small bowel follow through (SBFT) with barium has been the traditional imaging modality, cross sectional imaging using CT enterography (CTE) or MR enterography (MRE) have become increasingly utilized for preoperative SB assessment. The aim of this study was to assess changes in the utilization of SBFT versus CTE/MRE in UC and IBDu patients undergoing IPAA. METHODS: Prospectively generated clinical profiles on consecutive UC and IBDu patients undergoing IPAA between November 2006 and August 2019 were reviewed. Patients were classified into 2 groups: Group A (2006-2012) and Group B (2013-2019). Each patient was evaluated for preoperative SB imaging within their respective group. Baseline demographics were compared between groups. Imaging modalities included SBFT, CTE, MRE or ‘no imaging’. RESULTS: The study cohort of 354 patients had a mean age of 37.3 years (SD 17.1) years and included 50% males. Group A included 196 (55%) patients and Group B included 158 (45%) patients. Groups were comparable in terms of age, gender, and indication for surgery. Patients in Group A had a significantly longer disease duration (115 vs 85 months, P = 0.01) and greater number of IBDU patients (37% vs 22%, P < 0.01) versus UC patients (64% vs 77%, P < 0.01). When comparing imaging modalities, there was a significantly higher use of SBFT in Group A (44% vs 4%, P < 0.01), significantly higher use of CTE and MRE in Group B (11% vs 27%, P < 0.01 and 7% vs 40%, P < 0.01, respectively), and no difference in ‘no imaging’ between the two groups (32% vs 29%, P = 0.56). CONCLUSION(S): Cross sectional imaging using CTE or MRE has become the preferred modality of preoperative SB imaging in UC and IBDu patients undergoing IPAA.