Tumour-specific mesorectal excision for rectal cancer: Systematic review and meta-analysis of oncological and functional outcomes

BACKGROUND

Tumour-specific mesorectal excision (TSME) practice for rectal cancer only relies on small retrospective studies. This study aimed to perform a systematic review and meta-analysis to assess the oncological and functional outcomes of TSME practice.

METHODS

A systematic review protocol was drawn to include all the studies that compared partial versus total mesorectal excision (PME vs TME) practised for rectal adenocarcinoma up to 16 cm from the anal verge. A systematic literature search was conducted on EMBASE-Medline, Pubmed and Cochrane Library. Reports were screened for the study's outcomes: oncological radicality, postoperative anastomotic leak risk and functional outcomes. Included studies were appraised for risk-of-bias and meta-analysed. Evidence was rated with the GRADE approach.

RESULTS

Twenty-seven studies were included, consisting of 12325 patients (PME n = 4460, 36.2%; TME n = 7865, 63.8%). PME was performed for tumours higher than 10 cm from the anal verge in 54.5% of patients. There was no difference between PME and TME in circumferential resection margin positivity (OR 1.31, 95%CI 0.43-3.95, p = 0.64; I2 = 38%), and local recurrence risk (HR 1.05, 95%CI 0.52-2.10, p = 0.90; I2 = 40%). The postoperative leak risk (OR 0.42, 95%CI 0.27-0.67, p < 0.001; I2 = 60%) and the major low anterior resection syndrome risk (OR 0.34, 95%CI 0.28-0.40, p < 0.001; I2 = 0%) were lower after PME surgery. No difference was found in urinary incontinence (OR 0.68, 95%CI 0.13-3.67, p = 0.66) and urinary retention after early catheter removal (OR 2.00, 95%CI 0.24-16.51, p = 0.52).

CONCLUSIONS

Evidence from this meta-analysis shows that TSME for rectal cancer has good oncological results and leads to the best-fitted functional results possible for the patient's condition.

Impact of trans-anal versus laparoscopic total mesorectal excision on the surgical and pathologic outcomes of patients with rectal cancer: meta-analysis of randomized controlled trials

BACKGROUND

Despite its profound impact on the oncologic outcomes of rectal cancer, the most optimal surgical approach to total mesorectal excision (TME) has not been identified yet. All previous meta-analyses on this subject have been based on observational studies. This meta-analysis was conducted to assess the surgical and oncologic outcomes of laparoscopic TME (LaTME) compared to trans-anal TME (TaTME), utilizing only randomized controlled trials.

DESIGN

Systematic review and meta-analysis of randomized controlled trials.

METHODS

We searched electronic databases (MEDLINE, Cochrane CENTRAL, Clinicaltials.gov) from 2010 onwards, for all published clinical trials comparing TaTME to LaTME. Results are presented as risk ratios, with 95% CI, and pooled using the random effects model.

RESULTS

A total of 1691 patients, from 6 eligible randomized controlled trials, were included for analysis. Analyzed data showed no significant difference in morbidity (RR: 0.85, p = 0.15), mortality (RR: 0.50, p = 0.44), conversion to open (RR: 0.40, p = 0.07), or anastomotic leakage (RR: 0.73, p = 0.10) between TaTME and LaTME. There was also no difference in the rate of positive distal resection margin (DRM) (RR: 0.55, p = 0.10) or positive circumferential resection margin (CRM) (RR: 0.67, p = 0.30). Patients undergoing TaTME were more likely to have a complete TME (RR: 1.06, p = 0.002) and shorter hospital stays (RR: - 0.97, p < 0.00001).

CONCLUSIONS

Patients undergoing TaTME for rectal cancer were more likely to have a complete TME when compared to LaTME, though this did not translate into improved distal or circumferential resection margin. Additionally, TaTME and LaTME had similar surgical outcomes except for shorter length of stay with TaTME.

Transanal Total Mesorectal Excision for Rectal Cancer

Transanal total mesorectal excision (taTME) is a technique where rectal dissection is begun transanally in a "bottom-up" fashion. This technique facilitates dissection of the most distal part of the rectum and allows the establishment of the distal margin for rectal cancer. TaTME has proven its utility in facilitating low rectal dissection with significantly lower conversion rates and acceptable perioperative, oncological, and functional outcomes. However, taTME remains a challenging technique to learn and adopt. This article describes the technique, indications, and outcomes of taTME in rectal cancer during the last decade.

Involvement of tissue changes induced by neoadjuvant treatment in total mesorectal excision (TME): novel suggestions for determining TME quality

BACKGROUND

Few studies to date have investigated morphological changes after neoadjuvant treatment (NAT) and their implications in total mesorectal excision (TME). This study was primarily designed to evaluate whether tissue changes associated with NAT affected the quality of TME and additionally to suggest a more objective method evaluating TME quality.

METHODS

This study enrolled 1322 consecutive patients who underwent curative robot-assisted surgery for rectal cancer. Patients who did and did not receive NAT were subjected to propensity-score matching, yielding 402 patients in each group.

RESULTS

NAT independently reduced complete achievement of TME [odds ratio (OR) = 2.056, p = 0.017]. Intraoperative evaluation identified seven tissue changes significantly associated with NAT, including tumor perforation, mucin pool, necrosis, fibrosis, fat degeneration, and rectal or perirectal edema NAT (p < 0.001-0.05). Tumor perforation (OR = 5.299, p = 0.001) and mucin pool (OR = 14.053, p = 0.002) were independently associated with inappropriate (near-complete + incomplete) TME. Complete TME resulted in significantly reduced local recurrence (4.3% vs 15.3%, p = 0.003) and increased 5-year DFS rate (80.6% vs 67.6%, p = 0.047) compared with inappropriate one. By contrast, two tiers of complete and near-complete TMEs vs incomplete TME did not. Notably, among patients with complete TME, those who received NAT had a lower 5-year DFS than those who did not (77.8% vs 83.3%, p = 0.048).

CONCLUSIONS

NAT-associated tissue changes, somewhat interrupting complete TME, may provide unsolved clue to the relative inability of NAT to improve overall survival. The conventional three-tier grading of TME seems to be simplified into two tiers as complete and inappropriate.

Re-evaluation of controversial issues in the treatment of cT3N0-2 rectal cancer: a 10-year cohort analysis using propensity-score matching

BACKGROUND

Although neoadjuvant treatment is thought to provide optimal local control for stage II and III rectal cancers, many patients have been reported cured by total mesorectal excision (TME), alone or with additional chemotherapy (CTX).

METHODS

This study retrospectively evaluated outcomes in 2643 patients with cT3N0-2 rectal cancers undergoing curative TME during 2005-2015. Recurrence and survival outcomes were measured in three propensity-score matched groups, consisting of patients who underwent preoperative chemoradiotherapy (CRT) with postoperative CTX (NAPOC), postoperative CRT (POCRT), and exclusively postoperative CTX (EPOCT).

RESULTS

Near-complete or complete TME was conducted in more than 95.9% of patients and 80% of scheduled dose of postoperative CTX was completed in 99%. Except for higher SR rate in the POCRT group than the NAPOC group (p = 0.008), 5-year cumulative local and systemic recurrence (LR and SR) rates were 4.9% and 15.2% for cT3N0, and 4.2% and 21% for cT3N1-2 patients (LR, p = 0.703; SR, 0.065), respectively, with no significant differences associated with treatment exposure (p = 0.11-1). The 5-year cumulative disease-free (75.6% vs 65.7%, p = 0.018) and overall survival (87.1% vs 79.4%, p = 0.018 each) rates were higher in the NAPOC group than the POCRT group with cT3N1-2. However, any significant survival differences were not identified between the NAPOC and EPOCT groups according to tumor sub-stages or locations (p = 0.395-0.971).

CONCLUSIONS

We found any treatment modalities including competent TME and postoperative adjuvant CTX efficiently reducing LR generating robust survival outcome in the propensity-matched cohorts, demanding further randomized controlled trials by clinical sub-stages II-III.

Re-evaluation of possible vulnerable sites in the lateral pelvic cavity to local recurrence during robot-assisted total mesorectal excision

BACKGROUND

Despite mechanical and technical improvements in laparoscopic and robot-assisted (LAR) rectal cancer procedures, the absence of prognostic disparities among various approaches cannot improve the quality of TME. The present study re-evaluated robot-assisted total mesorectal excision (TME) procedures to determine whether these procedures may reveal technical faults that may increase the rate of local recurrence (LR).

METHODS

This study enrolled 886 consecutive patients with rectal cancer, who underwent curative robot-assisted LAR at Asan Medical Center (Seoul, Korea) between July 2010 and August 2017 (the first vs second period; n = 399 vs 487). The quality of TME and lateral pelvic mesorectal excision (LPME) were analyzed, as were LR rates and survival outcomes.

RESULTS

Complete TME and LPME were achieved in 89.2% and 80.1% of these patients, respectively, with ≤ 1% having incomplete TME excluding intramesorectal excision. LR rates were 13.5 and 14.5 times higher in patients with incomplete TME and LPME, respectively, than in patients with complete TME and LPME (14.8% vs 1.1% and 8.7% vs 0.6%; p < 0.001 each by univariate analyses). Multivariate analyses showed that defective LPME was independently associated with incomplete TME and vice versa (p < 0.001). Cox regression analysis showed that defective LPME was independently correlated with reduced 5-year disease-free survival rate (hazard ratio, 1.563; 95% confidence interval, 1.052-2.323; p = 0.027).

CONCLUSIONS

LR in rectal cancer patients was largely due to incomplete LPME, which was significantly associated with incomplete TME. Complete LPME may enhance the likelihood of complete TME, reducing LR rates.

A comparative cost analysis of transanal and laparoscopic total mesorectal excision for rectal cancer

Despite proven clinical benefits in the short term, technical difficulties limit utilization of laparoscopy in rectal cancer surgery (RCS). Transanal Total Mesorectal Excision (taTME) overcomes many technical limitations of laparoscopic RCS. However, the costs of this procedure have not been addressed yet. Our goal was to perform a comparative cost analysis of taTME and laparoscopic TME (lapTME). Consecutive patients undergoing curative TME between 1 February 2014 and 31 October 2018 were selected from a prospectively maintained database and stratified, according to the type of procedure, into taTME and lapTME groups. Patient demographics, tumour characteristics, operative parameters, and short-term outcomes were analyzed. The main outcome measure was intraoperative costs of the two procedures. Secondary outcomes were short-term outcome and the utilization of hospital resources to manage the postoperative course. Hundred and fifty-two patients with rectal cancer (66 lapTME, 86 taTME) were included in the study. Surgical supplies required for taTME procedure exceeded the cost of lapTME of 754,54 €. The duration of surgery was not significantly different between the two approaches (266 ± 92.85 vs 271 ± 83.63, p = 0.50). Short-term outcomes were comparable including postoperative complication rate (17 vs 20%, p = 0.68), reintervention rate, and length of stay. There was no difference in hospital resources utilization to manage postoperative course including blood test, diagnostics, consultations, and medications. TaTME has higher intraoperative costs in terms of supplies with respect to lapTME. Short-term outcomes and hospital resources to manage postoperative course are comparable.

Comparative Evaluation of the Short-Term Treatment Outcomes Between Open, Laparoscopic- and Robotic-Assisted Surgical Approaches for Rectal Cancer Treatment

The open surgeries and more recently minimal invasive surgeries aided by laparoscopic or robotic approaches are employed for rectal cancer treatment procedures. The open approach is the most commonly opted technique, but recent studies have also shown that laparoscopic total mesorectal excision (TME) has become the standard of care. There are certain shortcomings of laparoscopic surgery such as long learning curve, inadequate counter traction, limited dexterity, lack of tactile feedback and limited two-dimensional visions. Robotic surgery also offers several benefits to overcome the drawbacks of laparoscopic procedures, such as providing better dexterity and a more stable visualization. This study aims to analyse the surgical results in terms of completion of TME, short-term surgical outcomes and hospital stay in after open, laparoscopic- and robotic-assisted rectal resections respectively. A retrospective review of prospectively maintained database of patients operated for carcinoma rectum between January 2013 and August 2018 at Manipal Comprehensive Cancer Centre, Manipal-Vattikuti Institute of Robotic Surgery, Bangalore, was analysed in this study. The surgical parameters like completion of total mesorectal excision; proximal, distal and circumferential resection margins; number of nodes retrieved; and total post operative hospital stay were analysed in the open, laparoscopic-assisted and robotic-assisted groups. A total of 100 patients were included in the study consisting of 25, 25 and 50 patients each in the open, laparoscopic and robotic arms respectively. In case the desired results were not obtained using the advanced technique the procedure was converted and open technique was adopted. The conversion rate to open procedure was 8% (2of 25) in the laparoscopic-assisted group and 2% (1/50) in the robotic-assisted group. The average post operative hospital stay was 7.4, 7.36 and 6 days in the open, laparoscopic- and robotic-assisted group (p = 0.01) respectively. Robotic rectal resections show a trend towards better surgical results in the form of improved circumferential resection margins, completeness of TME and lower conversion rates.

Transanal total mesorectal excision (TaTME): current status and future perspectives

Total mesorectal excision (TME) is the gold standard surgical treatment for mid- and low rectal cancer; however, it is associated with specific technical hurdles. Transanal TME (TaTME) is a new procedure developed to overcome these difficulties, through an enhanced visualization of the dissection plane. This potentially could result in a more accurate distal dissection with a lower rate of positive circumferential resection margins, increasing the rate of sphincter-saving procedures. The indications for TaTME are currently expanding, despite not being yet standardized, and structured training programs are ongoing to help overcome the steep learning curve related to the technique. The procedure is feasible and safe with similar intraoperative complications and readmission rates when compared with conventional open or laparoscopic TME. Favorable short-term oncologic results have been reported: in particular, TaTME is associated with mesorectal specimen of a better quality and a longer distal resection margin that is established at the beginning of the procedure under direct view. Robotics, when available, will probably overcome the steep learning curve related to the complexity of TaTME. Long-term follow-up and ongoing RCT trials data are awaited regarding functional results, local recurrence and survival, and to facilitate the comparison with standard laparoscopic or robotic rectal resections. The present review is focused on critically analyzing the theoretical benefits and risks of the procedure, its indications, short- and long-term results and future direction in the application of TaTME.

The quality of total mesorectal excision specimen: A review of its macroscopic assessment and prognostic significance

As a surgical procedure which could significantly lower the recurrence rate of cancers, total mesorectal excision (TME) has been the gold standard for middle and lower rectal cancer treatment. However, previous studies have shown that the procedure did not achieve the ideal theoretical local recurrence rates of rectal cancers. Some researchers pointed out it was very likely that not all so-called TME treatments completely removed the mesorectum, implying that some of these TME surgical treatments failed to meet oncological quality standards. Therefore, a suitable assessment tool for the surgical quality of TME is necessary. The notion of “macroscopic assessment of mesorectal excision (MAME)” was put forward by some researchers as a better assessment tool for the surgical quality of TME and has been confirmed by a series of studies. Besides providing rapid and accurate surgical quality feedbacks for surgeons, MAME also effectively assesses the prognosis of patients with rectal cancer. However, as a new assessment tool used for TME surgical quality, MAME has an only limited influence on the current guidelines and is yet to be widely applied in most countries. The aims of this review are to provide a detailed introduction to MAME for clinical practice and to summarize the current prognostic significance of MAME.

Non-inferiority multicenter prospective randomized controlled study of rectal cancer T2-T3s (superficial) N0, M0 undergoing neoadjuvant treatment and local excision (TEM) vs total mesorectal excision (TME)

PURPOSE

The standard treatment of rectal adenocarcinoma is total mesorectal excision (TME), in many cases requires a temporary or permanent stoma. TME is associated with high morbidity and genitourinary alterations. Transanal endoscopic microsurgery (TEM) allows access to tumors up to 20 cm from the anal verge, achieves minimal postoperative morbidity and mortality rates, and does not require an ostomy. The treatment of T2, N0, and M0 cancers remains controversial. Preoperative chemoradiotherapy (CRT) in association with TEM reduces local recurrence and increases survival. The TAU-TEM study aims to demonstrate the non-inferiority of the oncological outcomes and the improvement in morbidity and quality of life achieved with TEM compared with TME.

METHODS

Prospective, multicenter, randomized controlled non-inferiority trial includes patients with rectal adenocarcinoma less than 10 cm from the anal verge and up to 4 cm in size, staged as T2 or T3-superficial N0-M0. Patients will be randomized to two areas: CRT plus TEM or radical surgery (TME). Postoperative morbidity and mortality will be recorded and patients will complete the quality of life questionnaires before the start of treatment, after CRT in the CRT/TEM arm, and 6 months after surgery in both arms. The estimated sample size for the study is 173 patients. Patients will attend follow-up controls for local and systemic relapse.

CONCLUSIONS

This study aims to demonstrate the preservation of the rectum after preoperative CRT and TEM in rectal cancer stages T2-3s, N0, M0 and to determine the ability of this strategy to avoid the need for radical surgery (TME).

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01308190. Número de registro del Comité de Etica e Investigación Clínica (CEIC) del Hospital universitario Parc Taulí: TAU-TEM-2009-01.

Anterior resection for rectal cancer with mesorectal excision: institutional review

This study aims to compare the operative results and oncological outcomes of patients with total mesorectal excision (TME) for mid and distal cancer and partial mesorectal excision (PME) for proximal cancer. Anterior resection has become the preferred treatment option for rectal cancer. TME with sharp dissection has been shown to be associated with a low local recurrence rate. Controversies still exist as to the need for TME in more proximal tumor. Resection of primary rectal and rectosigmoid cancer was performed in 298 patients from January 2003 to November 2010. These 298 patients (163 men and 135 women; median age, 67 years) underwent anterior resection. The curative resection was performed in 269 patients (90.3 %). TME was performed in 202 patients (67.8 %). Significantly longer median operating time, more blood loss, and a longer hospital stay were found in patients with TME. The overall operative mortality and morbidity rates were 1.8 % and 32.6 %, respectively, and there were no significant differences between those of TME and PME. Anastomotic leak occurred in 8.1 % and 1.3 % of patients with TME and PME, respectively (P < 0.001). Independent factors for a higher anastomotic leakage rate were TME, the malegender, the absence of stoma, and increased blood loss. The advanced stage of the disease and the performance of coloanal anastomosis were independent factors for increased local recurrence. By performing TME in patients with mid and distal rectal cancer, the local control and survival of these patients are similar to those of patients with proximal cancers where adequate clearance can be achieved by PME.

Single-port laparoscopic total mesorectal excision with transanal resection (transabdominal transanal resection) for low rectal cancer: initial experience with 22 cases

BACKGROUND

Total mesorectal excisions (TME) with transanal resection and coloanal anastomosis (CAA) represent one of the standard surgical treatments for low rectal cancers. We report our initial experiences with trans-abdominal trans-anal resections (TATAR) with TME, performed using a single-port laparoscopic surgeries (SPLS) approach for low rectal cancers.

METHODS

Between June 2009 and April 2011, 22 low rectal cancer patients underwent SPLS TATAR with TME. SPLS was performed transumbilically or through predetermined stoma sites. Conventional laparoscopic instruments were used, and the intracorporeal procedures and range of operation did not differ. After a full laparoscopic TME to the pelvic floor muscles, the specimen was pulled through the anus. CAA was completed with transanal hand sewn sutures. Patient and tumor characteristics and operative, pathologic, and postoperative outcomes were studied.

RESULTS

SPLS TATAR with TME was successful in all patients. No additional incisions for trocars or conversions to open surgery were performed. The median incision length, operative time, and postoperative length of stay were 2.0 cm (range: 1.5-2.5), 260 min (range: 190-380), and 6 days (range: 4-16), respectively. The median number of harvested lymph nodes was 22 (range: 9-42). The median distal margin from the tumor was 2.0 cm (range: 0.3-4.0). No intraoperative complications were noted.

CONCLUSIONS

SPLS TATAR with TME was safe and feasible. In addition to cosmetic advantages, oncologic requirements for specimens, including adequate margins and sufficient lymph node harvesting could be fulfilled entirely. However, the technique and oncologic safety warrant further evaluation and prospective randomized studies.