What is total mesorectal excision surgery?

1.

Elsevier ClinicalKey Clinical Overview

Treatment Subsubsection Title: Procedures: Subsubsection Title: Surgical resection: Subsubsection Title: General explanation: Surgical removal of tumor; approach depends on location and stage of lesion Extent of resection should correspond to lymphovascular drainage of site of colon cancer Resection of adherent or grossly involved adjacent organs should be en bloc Curative resection of rectal cancer also involves removing the blood supply and lymphatics from the origin of the superior rectal artery Synchronous colon cancers may be treated by 2 separate resections or subtotal colectomy Optimal bowel preparation for elective colorectal surgery consists of mechanical bowel preparation in combination with oral antibiotics Laparoscopic approach is associated with reduced morbidity and similar oncological outcomes Subsubsection Title: Indication: Polypectomy via colonoscopy may be sufficient for stage 0 or I colon or rectal lesions if no evidence of high-risk features exists, such as: Angiolymphatic invasion Positive margin of resection Unfavorable histologic features Transanal resection may be performed to remove small (less than 3 cm) rectal lesions located within 8 cm of anal verge Disadvantage is lack of regional node resection Transabdominal resection with total mesorectal excision is advised for other resectable rectal lesions (ie, larger or more proximal stage I lesions, stages II and III lesions) Transanal total mesorectal excision is a proposed alternative approach; however, this is subject to controversy regarding its technical learning curve, perioperative complications, and the lack of long-term data on oncologic outcomes British guidelines recommend this only in the context of research

2.

Chu, Edward (2024). In Goldman-Cecil Medicine (pp. 1343). DOI: 10.1016/B978-0-323-93038-3.00179-9

SurgerySurgical resection is the primary treatment for early-stage, locally confined colon cancer (stage 0 and stage I). Highly selected patients with site-limited metastatic disease (stage IV) also may undergo surgery with curative intent. Curative surgery aims to remove the primary tumor with tumor-free margins, as well as to remove the primary feeding arterial vessel and corresponding lymphatics en bloc. A minimum of 12 lymph nodes should be removed and examined microscopically for accurate staging. Synchronous colon cancers can be removed individually by subtotal colectomy. Any adjacent adherent structures should be resected en bloc. Prophylactic oophorectomy is not recommended, but if one ovary is grossly involved, the other should be removed as well given the risk of contralateral involvement. Laparoscopic resection is as safe and effective as open resection and requires a modestly shorter recovery time.For rectal cancer, the main goal of surgery is to preserve the function of the anal sphincter. For cancers involving the distal rectum, the recommendation is total mesorectal excision with en bloc removal of the lymphovascular and fatty envelope surrounding the rectum. For upper rectal tumors, by comparison, tumor-specific mesorectal excision (en bloc removal of the mesorectum 5cm distal to the tumor) is sufficient. For minimal-risk (T1 disease, size <3cm, well differentiated, within 8cm of the anal verge, no lymphovascular invasion, and less than one third circumferential) low rectal cancers, local transanal excision is acceptable. Postoperatively, increased bowel frequency is common, and some patients develop fecal incontinence or evacuation dysfunction (Chapter 131). As such, the main focus in patients with rectal cancer is to preserve the function of the anal sphincter.Obstructing tumors should be immediately resected with bowel re-anastomosis.

3.

Sun Myint A, Rao C, Barbet N, et al. The Safety and Efficacy of Total Mesorectal Excision (TME) Surgery Following Dose-Escalation: Surgical Outcomes From the Organ Preservation in Early Rectal Adenocarcinoma (OPERA) Trial, a European Multicentre Phase 3 Randomised Trial (NCT02505750). Colorectal Disease : The Official Journal of the Association of Coloproctology of Great Britain and Ireland. 2023;25(11):2160-2169. doi:10.1111/codi.16773.

Publish date: November 3, 2023.

Patients were assessed at 14, 20 and 24 weeks from the start of treatment. Watch and wait management was adopted for patients who achieved a clinical complete response (cCR) at 24 weeks following treatment. Either local excision (LE) or TME surgery was offered for residual disease or local regrowth, according to patient and surgeon preference. Surgical morbidity and mortality were recorded prospectively. RESULTS: Between July 2015 and June 2020, 148 patients were randomised of which 141 were evaluable in March 2022. At median follow-up of 38.2 months (range: 34.2-42.5), surgery was performed for 66 (47%) patients. A total of 27 (20%) patients had local excision and 39 (29%) had TME surgery, 22/39 (56%) underwent anterior resection and 17/39 (44%) underwent abdominoperineal excision of the rectum. The R0 resection rate was 87%. There were no deaths, and six patients (15%) had Clavien-Dindo IIIb complications.

4.

Igaki T, Kitaguchi D, Kojima S, et al. Diseases of the Colon and Rectum. 2022;65(5):e329-e333. doi:10.1097/DCR.0000000000002393.

Publish date: May 0, 2022.

BACKGROUND: Total mesorectal excision is the standard surgical procedure for rectal cancer because it is associated with low local recurrence rates. To the best of our knowledge, this is the first study to use an image-guided navigation system with total mesorectal excision. IMPACT OF INNOVATION: The impact of innovation is the development of a deep learning-based image-guided navigation system for areolar tissue in the total mesorectal excision plane. Such a system might be helpful to surgeons because areolar tissue can be used as a landmark for the appropriate dissection plane. TECHNOLOGY, MATERIALS, AND METHODS: This was a single-center experimental feasibility study involving 32 randomly selected patients who had undergone laparoscopic left-sided colorectal resection between 2015 and 2019. Deep learning-based semantic segmentation of areolar tissue in the total mesorectal excision plane was performed. Intraoperative images capturing the total mesorectal excision scene extracted from left colorectal laparoscopic resection videos were used as training data for the deep learning model. Six hundred annotation images were created from 32 videos, with 528 images in the training and 72 images in the test data sets. The experimental feasibility study was conducted at the Department of Colorectal Surgery, National Cancer Center Hospital East, Chiba, Japan. Dice coefficient was used to evaluate semantic segmentation accuracy for areolar tissue. PRELIMINARY RESULTS: The developed semantic segmentation model helped locate and highlight the areolar tissue area in the total mesorectal excision plane. The accuracy and generalization performance of deep learning models depend mainly on the quantity and quality of the training data. This study had only 600 images; thus, more images for training are necessary to improve the recognition accuracy.

5.

Liu H, Chang Y, Li A, et al. International Journal of Surgery (London, England). 2022;99:106263. doi:10.1016/j.ijsu.2022.106263.

Publish date: March 2, 2022.

BACKGROUND: Total mesorectal excision (TME) is conventionally performed according to Heald's principles through the so-called 'holy plane', between the visceral and parietal fasciae. However, urinary and sexual dysfunctions remain frequent postoperative complications. We proposed to preserve urogenital fascia (UGF) in TME, and this study aimed to clarify the anatomical basis of this technique and evaluate its efficacy and safety. MATERIALS AND METHODS: Cadaveric dissection was performed on 26 pelvises, and laparoscopic TME with UGF preservation was performed in 212 patients with mid-low rectal cancer. The fasciae and spaces related to TME were observed and described, and the clinical effect of UGF-preserving TME was analyzed. RESULTS: In the 26 cadavers, fascia propria of the rectum (FPR) presents as a fibrous capsule enveloping the mesorectum. UGF extends postero-laterally to the rectum, enveloping the hypogastric nerves and ureters. We demonstrated that the visceral fascia is actually the UGF, and FPR and visceral fascia (i.e. UGF) are two independent layers of fascia. Thus, FPR, UGF and parietal fascia form two avascular spaces behind the rectum. The plane ventral to the UGF is the real 'holy plane' for TME, rather than that dorsal to the UGF as is traditionally thought.

6.

Glynne-Jones R, Wyrwicz L, Tiret E, et al. Annals of Oncology : Official Journal of the European Society for Medical Oncology. 2017;28(suppl_4):iv22-iv40. doi:10.1093/annonc/mdx224.

Publish date: July 6, 2017.

]. The standard of care for surgery is TME, implying that all of the mesorectal fat, including all lymph nodes, should be meticulously excised [III, A]. A partial mesorectal excision with a distal margin of at least 5 cm of mesorectum can be considered in high rectal cancer. In rare situations, local excision can be an option in patients with a cT1 tumour or in elderly or fragile patients. TEM is then the procedure of choice. In selecting laparoscopic or open surgery, the surgeon should take into account his/her experience with the technique, the stage and location of the cancer and patient factors such as obesity and previous open abdominal surgery. In the case of low rectal tumours, transanal TME (TaTME) may facilitate pelvic and distal mesorectal dissection, but standardisation and assessment of the technique are necessary []. If an abdominoperineal excision is planned and the tumour extends into the levators, a cylindrical specimen should be achieved, avoiding a ‘waist’ effect and minimising the risk of a positive CRM and/or an R1/2 resection [ In Japan, lateral node dissection (LND) is practised if the tumour is sited below the peritoneal reflection to reduce the risk of pelvic recurrence and improve overall survival (OS). Lateral pelvic nodes are often invaded if multiple mesorectal nodes are involved [ These early, favourable cases, which are not suitable for local excision, i.e. cT1-2 but with adverse pathological features (e.g. G3, V1, L1), and some cT3a/b without clear involvement of MRF (MRF-) according to MRI, when located above the levators, may be appropriate for surgery alone with TME [II, A], as the risk of local failure is very low. Although not prospectively assessed, EMVI on MRI, even in the case of cT3a/b tumours, confers a higher risk of local and distant recurrence [