Endorectal ultrasound in the identification of rectal tumors for transanal endoscopic surgery: factors influencing its accuracy

How to Study the Location and Size of Rectal Tumors That Are Candidates for Local Surgery: Rigid Rectoscopy, Magnetic Resonance, Endorectal Ultrasound or Colonoscopy? An Interobservational Study

1.

BACKGROUND

Preoperative staging of rectal lesions for transanal endoscopic surgery (TES) comprises digital rectal examination, intraoperative rigid rectoscopy (IRR), endorectal ultrasound (EUS), colonoscopy and rectal magnetic resonance imaging (rMRI). The gold standard for topographic features is IRR. Are the results of the other tests sufficiently reliable to eliminate the need for IRR? rMRI is a key test in advanced rectal cancer and is not operator-dependent. Description of anatomical landmarks is variable. Can we rely on the information regarding topographic features provided by all radiologists? 2.

MATERIALS AND METHODS

This is a concordance interobservational study involving four diagnostic tests of anatomical characteristics of rectal lesions (colonoscopy, EUS, rectal MRI and IRR), performed by four expert radiologists, regarding topographic rectal features with rMRI. 3.

RESULTS

Fifty-five rectal tumors were operated on by using TES. The distance of the tumor from the anal verge, location by quadrants, size by quadrants and size of tumor were assessed (IRR as gold standard). For most of the tumors, the correlation between IRR and colonoscopy or EUS was very good (ICC > 0.75); the correlation between rMRI and IRR in respect of the size by quadrants (ICC = 0.092) and location by quadrants (ICC = 0.292) was weak. Topographic landmarks studied by the expert radiologists had an excellent correlation, except for distance from the peritoneal reflection to the anal verge (ICC = 0.606). 4.

CONCLUSIONS

Anatomical description of rectal lesions by IRR, EUS, colonoscopy and rMRI is reliable. Topographic data obtained by EUS and colonoscopy can serve as a reference to avoid IRR. Determination of these topographic data by rMRI is less reliable. As performed by the expert radiologists, the anatomical study by rMRI is accurate and reproducible.

Magnifying chromoendoscopy is a reliable method in the selection of rectal neoplasms for local excision

PURPOSE

Adequate staging of early rectal neoplasms is essential for organ-preserving treatments, but magnetic resonance imaging (MRI) frequently overestimates the stage of those lesions. We aimed to compare the ability of magnifying chromoendoscopy and MRI to select patients with early rectal neoplasms for local excision.

METHODS

This retrospective study in a tertiary Western cancer center included consecutive patients evaluated by magnifying chromoendoscopy and MRI who underwent en bloc resection of nonpedunculated sessile polyps larger than 20 mm, laterally spreading tumors (LSTs) [Formula: see text] 20 mm, or depressed-type lesions of any size (Paris 0-IIc). Sensitivity, specificity, accuracy, and positive and negative predictive values of magnifying chromoendoscopy and MRI to determine which lesions were amenable to local excision (i.e., [Formula: see text] T1sm1) were calculated.

RESULTS

Specificity of magnifying chromoendoscopy was 97.3% (95% CI 92.2-99.4), and accuracy was 92.7% (95% CI 86.7-96.6) for predicting invasion deeper than T1sm1 (not amenable to local excision). MRI had lower specificity (60.5%, 95% CI 43.4-76.0) and lower accuracy (58.3%, 95% CI 43.2-72.4). Magnifying chromoendoscopy incorrectly predicted invasion depth in 10.7% of the cases in which the MRI was correct, while magnifying chromoendoscopy provided a correct diagnosis in 90% of the cases in which the MRI was incorrect (p = 0.001). Overstaging occurred in 33.3% of the cases in which magnifying chromoendoscopy was incorrect and 75% of the cases in which MRI was incorrect.

CONCLUSION

Magnifying chromoendoscopy is reliable for predicting invasion depth in early rectal neoplasms and selecting patients for local excision.

Prediction of lymph node metastasis in stage T1-2 rectal cancers with MRI-based deep learning

OBJECTIVES

This study aimed to investigate whether a deep learning (DL) model based on preoperative MR images of primary tumors can predict lymph node metastasis (LNM) in patients with stage T1-2 rectal cancer.

METHODS

In this retrospective study, patients with stage T1-2 rectal cancer who underwent preoperative MRI between October 2013 and March 2021 were included and assigned to the training, validation, and test sets. Four two-dimensional and three-dimensional (3D) residual networks (ResNet18, ResNet50, ResNet101, and ResNet152) were trained and tested on T2-weighted images to identify patients with LNM. Three radiologists independently assessed LN status on MRI, and diagnostic outcomes were compared with the DL model. Predictive performance was assessed with AUC and compared using the Delong method.

RESULTS

In total, 611 patients were evaluated (444 training, 81 validation, and 86 test). The AUCs of the eight DL models ranged from 0.80 (95% confidence interval [CI]: 0.75, 0.85) to 0.89 (95% CI: 0.85, 0.92) in the training set and from 0.77 (95% CI: 0.62, 0.92) to 0.89 (95% CI: 0.76, 1.00) in the validation set. The ResNet101 model based on 3D network architecture achieved the best performance in predicting LNM in the test set, with an AUC of 0.79 (95% CI: 0.70, 0.89) that was significantly greater than that of the pooled readers (AUC, 0.54 [95% CI: 0.48, 0.60]; p < 0.001).

CONCLUSION

The DL model based on preoperative MR images of primary tumors outperformed radiologists in predicting LNM in patients with stage T1-2 rectal cancer.

KEY POINTS

• Deep learning (DL) models with different network frameworks showed different diagnostic performance for predicting lymph node metastasis (LNM) in patients with stage T1-2 rectal cancer. • The ResNet101 model based on 3D network architecture achieved the best performance in predicting LNM in the test set. • The DL model based on preoperative MR images outperformed radiologists in predicting LNM in patients with stage T1-2 rectal cancer.

Short-term outcomes of chemoradiotherapy and local excision versus total mesorectal excision in T2-T3ab,N0,M0 rectal cancer: a multicentre randomised, controlled, phase III trial (the TAU-TEM study)

BACKGROUND

The standard treatment of T2-T3ab,N0,M0 rectal cancers is total mesorectal excision (TME) due to the high recurrence rates recorded with local excision. Initial reports of the combination of pre-operative chemoradiotherapy (CRT) and transanal endoscopic microsurgery (TEM) have shown reductions in local recurrence. The TAU-TEM study aims to demonstrate the non-inferiority of local recurrence and the improvement in morbidity achieved with CRT-TEM compared with TME. Here we describe morbidity rates and pathological outcomes.

PATIENTS AND METHODS

This was a prospective, multicentre, randomised controlled non-inferiority trial including patients with rectal adenocarcinoma staged as T2-T3ab,N0,M0. Patients were randomised to the CRT-TEM or the TME group. Patients included, tolerance of CRT and its adverse effects, surgical complications (Clavien-Dindo and Comprehensive Complication Index classifications) and pathological results (complete response in the CRT-TEM group) were recorded in both groups. Patients attended follow-up controls for local and systemic relapse.

TRIAL REGISTRATION

NCT01308190.

RESULTS

From July 2010 to October 2021, 173 patients from 17 Spanish hospitals were included (CRT-TEM: 86, TME: 87). Eleven were excluded after randomisation (CRT-TEM: 5, TME: 6). Modified intention-to-treat analysis thus included 81 patients in each group. There was no mortality after CRT. In the CRT-TEM group, one patient abandoned CRT, 1/81 (1.2%). The CRT-related morbidity rate was 29.6% (24/81). Post-operative morbidity was 17/82 (20.7%) in the CRT-TEM group and 41/81 (50.6%) in the TME group (P < 0.001, 95% confidence interval 42.9% to 16.7%). One patient died in each group (1.2%). Of the 81 patients in the CRT-TEM group who received the allocated treatment, 67 (82.7%) underwent organ preservation. Pathological complete response in the CRT-TEM group was 44.3% (35/79). In the TME group, pN1 were found in 17/81 (21%).

CONCLUSION

CRT-TEM treatment obtains high pathological complete response rates (44.3%) and a high CRT compliance rate (98.8%). Post-operative complications and hospitalisation rates were significantly lower than those in the TME group. We await the results of the follow-up regarding cancer outcomes and quality of life.

Transanal Local Excision or Endoscopic Dissection for Benign and Large Lesions of the Rectum

Since the introduction of transanal endoscopic microsurgery, local excision of "early" rectal lesions has offered the possibility to reduce the invasiveness of treatment for the limited disease. Flexible endoscopy techniques allow today different alternatives consisting of endoscopic mucosal resection or endoscopic submucosal dissection. The first is a straightforward and relatively easy technique, but it prevents a correct pathological staging of the lesion due to fragmentation and the verification of disease-free margins. The second relies on operators' audacity depending on their increasing experience due to the limited progress in technology. What is the preferable technique today is questionable. All the methods have pros and cons. The future certainly will see the use of ideal systems, allowing the possibility of precision surgery for partial- or full-thickness excision, depending on intraoperative findings, and the extension above the rectosigmoid junction. Miniaturized flexible robotic devices may represent the solution for both issues.

Preoperative Diagnostic Uncertainty in T2-T3 Rectal Adenomas and T1-T2 Adenocarcinomas and a Therapeutic Dilemma: Transanal Endoscopic Surgery, or Total Mesorectal Excision?

BACKGROUND

Endorectal ultrasound and rectal magnetic resonance are sometimes unable to differentiate between stages T2 and T3 in rectal adenomas that are possible adenocarcinomas, or between stages T1 and T2 in rectal adenocarcinomas. These cases of diagnostic uncertainty raise a therapeutic dilemma: transanal endoscopic surgery (TES) or total mesorectal excision (TME)?

METHODS

An observational study of a cohort of 803 patients who underwent TES from 2004 to 2021. Patients operated on for adenoma (group I) and low-grade T1 adenocarcinoma (group II) were included. The variables related to uncertain diagnosis, and to the definitive pathological diagnosis of adenocarcinoma stage higher than T1, were analyzed.

RESULTS

A total of 638 patients were included. Group I comprised 529 patients, 113 (21.4%) with uncertain diagnosis. Seventeen (15%) eventually had a pathological diagnosis of adenocarcinoma higher than T1. However, the variable diagnostic uncertainty was a risk factor for adenocarcinoma above T1 (OR 2.3, 95% CI 1.1-4.7). Group II included 109 patients, eight with uncertain diagnosis (7.3%). Two patients presented a definitive pathological diagnosis of adenocarcinoma above T1.

CONCLUSIONS

On the strength of these data, we recommend TES as the initial indication in cases of diagnostic uncertainty. Multicenter studies with larger samples for both groups should now be performed to further assess this strategy of initiating treatment with TES.

Long-term outcomes of endoscopic submucosal dissection and transanal endoscopic microsurgery for the treatment of rectal tumors

BACKGROUND AND AIM

Endoscopic submucosal dissection and transanal endoscopic microsurgery are good options for the treatment of rectal adenomas and early rectal carcinomas, but whether long-term outcomes of these procedures are comparable is not known. The aim of this study was to address this question.

METHODS

A retrospective single-center study evaluating 98 consecutive procedures between June 2008 and December 2017 was performed in a tertiary cancer center. Consecutive patients who had undergone either endoscopic submucosal resection or transanal endoscopic microsurgery for rectal adenomas and early rectal carcinomas were evaluated, and long-term recurrence and complication rates were compared.

RESULTS

Both groups were similar regarding sex, age, preoperative surgical risk, and en bloc resection rate (95.7% in the endoscopic and 100% in the surgical group, P = 0.81). Mean follow-up period was 37.6 months. Lesions resected endoscopically were significantly larger (68.5 mm) than those resected by transanal resection (44.5 mm), P = 0.003. Curative resections occurred in 97.2% of endoscopic resections and 85.2% of the surgical ones (P = 0.04). Comparing resections that fulfilled histologic curative criteria, there were no recurrences in the endoscopic group (out of 69 cases) and two recurrences in the transanal group (8.3% of 24 cases), P = 0.06. Late complications occurred in 12.7% of endoscopic procedures and 25.9% of surgical procedures (P = 0.13).

CONCLUSIONS

In our experience, endoscopic submucosal resection seems to have advantages over transanal endoscopic microsurgery, with similar en bloc resection rate and lower rate of late complications and recurrences. Multicenter randomized controlled trials are needed to support our findings.

Completion Surgery in Unfavorable Rectal Cancer after Transanal Endoscopic Microsurgery: Does It Achieve Satisfactory Sphincter Preservation, Quality of Total Mesorectal Excision Specimen, and Long-term Oncological Outcomes?

BACKGROUND

Unfavorable adenocarcinoma after transanal endoscopic microsurgery requires "completion surgery" with total mesorectal excision. The literature on this procedure is very limited.

OBJECTIVE

This study aims to assess the percentage of transanal endoscopic microsurgery that will require completion surgery.

DESIGN

This is an observational study with prospective data collection and retrospective analysis from patients who were operated on consecutively.

SETTINGS

The study was conducted at a single academic institution.

PATIENTS

Patients undergoing transanal endoscopic microsurgery from June 2004 to December 2018 who later required total mesorectal excision were included.

MAIN OUTCOME MEASURES

All the patients followed the same protocol: preoperative study, indication of transanal endoscopic microsurgery with curative intent, performance of transanal endoscopic microsurgery, and completion surgery indication 3 to 4 weeks after transanal endoscopic microsurgery.

RESULTS

Seven hundred seventy-four patients underwent transanal endoscopic microsurgery, 622 with curative intent (group I: adenoma, 517; group II: adenocarcinoma, 105). Completion surgery was indicated in 64 of 622 (10.3%) patients: group I, 40 of 517 (7.7%) and group II, 24 of 105 (22.9%). After applying exclusion criteria, completion surgery was performed in 55 patients (8.8%). Abdominoperineal resection was performed in 23 (45.1%); the initial lesion was within 6 cm of the anal verge in 19 of these 23 (82.6%). The clinical morbidity rate (Clavien Dindo> II) was 3 of 51 (5.9%). Total mesorectal excision was graded as complete in 42 of 49 (85.7%). The circumferential resection margin was tumor-free in 47 of 50 (94%). Median follow-up was 58 months. Local recurrence was recorded in 2 of 51 (3.9%) and systemic recurrence was recorded in 7 of 51 (13.7%); 5-year disease-free survival was 86%.

LIMITATIONS

The limitations are defined by the study's observational design and the retrospective analysis.

CONCLUSION

The indication of completion surgery after transanal endoscopic microsurgery is low, but is higher in the indication of adenocarcinoma. Compared with initial total mesorectal excision, completion surgery requires a higher rate of abdominoperineal resection, but has similar postoperative morbidity, total mesorectal excision quality, and oncological results. See Video Abstract at http://links.lww.com/DCR/B423.

CIRUGA COMPLEMENTARIA EN CNCER DE RECTO DESFAVORABLE DESPUS DE UNA TEM SE OBTIENE SATISFACTORIAMENTE PRESERVACIN DEL ESFNTER, CALIDAD DE MUESTRA DE ETM Y RESULTADOS ONCOLGICOS A LARGO PLAZO

ANTECEDENTES:El adenocarcinoma con evolución desfavorable luego de una de microcirugía endoscópica transanal (TEM) requiere "cirugía de finalización" con la excisión total del mesorecto. La literatura sobre este procedimiento es muy limitada.OBJETIVO:Evaluar el porcentaje de microcirugía endoscópica transanal que requerió cirugía completa.DISEÑO:Estudio observacional con recolección prospectiva de datos y análisis retrospectivo de pacientes operados consecutivamente.AJUSTES:El estudio se realizó en una sola institución académica.PACIENTES:Aquellos pacientes sometidos a microcirugía endoscópica transanal desde junio de 2004 hasta diciembre de 2018 que luego requirieron excisón toztal del mesorecto.PRINCIPALES MEDIDAS DE RESULTADO:Todos los pacientes siguieron el mismo protocolo: estudio preoperatorio, indicación de microcirugía endoscópica transanal con intención curativa, realización de microcirugía endoscópica transanal e indicación de cirugía complementaria 3-4 semanas después de la microcirugía endoscópica transanal.RESULTADOS:Setecientos setenta y cuatro pacientes fueron sometidos a microcirugía endoscópica transanal, 622 con intención curativa (grupo I, adenoma: 517, grupo II, adenocarcinoma: 105). la cirugía complementaria fué indicada en 64/622 (10.3%), grupo I: 40/517 (7.7%) y grupo II 24/105 (22.9%). Después de aplicar los criterios de exclusión, la cirugía complementaria se realizó en 55 pacientes (8,8%). La resección abdominoperineal fué realizada en 23 (45,1%); en 19 de estos casos 23 (82,6%) la lesión inicial se encontraba dentro los 6 cm del margen anal. La tasa de morbilidad clínica (Clavien-Dindo > II) fue de 3/51 (5,9%). La excisión total del mesorecto se calificó como completa en 42/49 (85,7%). El margen de resección circunferencial se encontraba libre de tumor en 47/50 (94%). La mediana de seguimiento fue de 58 meses. La recurrencia local se registró en 2/51 (3.9%) y la recurrencia sistémica en 7/51 (13.7%); La supervivencia libre de enfermedad a 5 años fue del 86%.LIMITACIONES:Todas definidas por el diseño observacional y el análisis retrospectivo del mismo.CONCLUSIÓN:La indicación de completar la cirugía después de una TEM es baja, pero es más alta cuando la indicación es por adenocarcinoma. En comparación con la excisión total del mesorecto inicial, la cirugía complementaria requiere una tasa más alta de resección abdominoperineal, pero tiene una morbilidad postoperatoria, una calidad de excisión total del mesorecto y resultados oncológicos similares. ConsulteVideo Resumen en http://links.lww.com/DCR/B423. (Traducción-Dr. Xavier Delgadillo).

Comparison of Clinical Efficacy and Safety Between da Vinci Robotic and Laparoscopic Intersphincteric Resection for Low Rectal Cancer: A Meta-Analysis

Background and Aims: The intersphincteric resection (ISR) is beneficial for saving patients' anus to a large extent and restoring original bowel continuity. Laparoscopic ISR (L-ISR) has its drawbacks, such as two-dimensional images, low motion flexibility, and unstable lens. Recently, da Vinci robotic ISR (R-ISR) is increasingly used worldwide. The purpose of this article is to compare the feasibility, safety, oncological outcomes, and clinical efficacy of R-ISR vs. L-ISR for low rectal cancer. Methods: PubMed, EMBASE, Cochrane Library, and Web of Science were searched to identify comparative studies of R-ISR vs. L-ISR. Demographic, clinical, and outcome data were extracted. Mean difference (MD) and risk ratio (RR) with their corresponding confidence intervals (CIs) were calculated. Results: Five studies were included. In total, 510 patients were included, of whom 273 underwent R-ISR and 237 L-ISR. Compared with L-ISR, R-ISR has significantly lower estimated intraoperative blood loss (MD = -23.31, 95% CI [-41.98, -4.64], P = 0.01), longer operative time (MD = 51.77, 95% CI [25.68, 77.86], P = 0.0001), hospitalization days (MD = -1.52, 95% CI [-2.10, 0.94], P < 0.00001), and postoperative urinary complications (RR = 0.36, 95% CI [0.16, 0.82], P = 0.02). Conclusions: The potential benefits of R-ISR are considered as a safe and feasible alternative choice for the treatment of low rectal tumors.

Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

BACKGROUND

Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up.

METHOD

Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence.

RESULTS

TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis.

CONCLUSION

TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.