Factors influencing the quality of total mesorectal excision

Laparoscopic surgery for rectal cancer, specimen extraction: transanal or transabdominal?

BACKGROUND

Comparison of natural orifice specimen extraction (NOSE) and transabdominal specimen extraction (TASE) in colorectal surgery remains controversial. Herein, we aimed to perform a retrospective analysis on surgical outcomes of NOSE and TASE at three hospitals in east of Iran.

METHOD

Consecutive locally advanced rectal adenocarcinoma patients who underwent laparoscopic surgery using either NOSE or TASE from 2011 to 2017 were recruited. These patients were followed-up till 2020. Data, including postoperative complications, long-term overall and recurrence-free survival were analyzed retrospectively.

RESULTS

239 eligible patients were included in this study. 169 (70.71%) patients underwent NOSE, and 70 (29.29%) patients underwent TASE. Although this study has achieved similar outcomes in terms of overall and recurrence-free survival, metastasis, circumferential margin involvement as well as complications of intra-operative bleeding, obstruction, anastomosis-fail, rectovaginal-fistula in women and pelvic collection/abscess in both groups, we observed higher rates of locoregional recurrence, incontinency, stenosis and the close distal margins involvement in NOSE group and also obstructed defecation syndrome in TASE cases.

CONCLUSION

According to our findings, NOSE laparoscopic surgery showed significantly higher incontinency, impotency, stenosis and involvement of the close distal margins rates. Nevertheless, considering the similarity of long-term overall and recurrence-free survival, metastasis, circumferential margin involvement, NOSE procedure is still could be considered as a second choice for lower rectal adenocarcinoma patients.

Laparoscopic intersphincteric resection vs. transanal total mesorectal excision in overweight patients with low rectal cancer

Objective

Anus-preserving surgery in overweight patients with low rectal cancer has been a challenge due to the narrow operating space. Intersphincteric resection (ISR) was once a standard therapeutic option for low rectal cancer. The effectiveness of transanal total mesorectal excision (taTME) in treating this group of patients remains uncertain as a new surgical strategy. The aim of this study was to evaluate the short-term effects of taTME with ISR in overweight patients with low rectal cancer.

Methods

A total of 53 patients with low rectal cancer were treated with taTME in 31 cases and ISR in 22 cases. The surgery-related data, pathological manifestations of surgical specimens, postoperative recovery, and postoperative complications were compared.

Results

Patients in both groups completed the surgery successfully. There were no significant differences in operative time, blood loss, anastomotic distance from the anal verge and ileostomy between the two groups (P > 0.05). TaTME group performed or virtually finished resection of the rectal mesentery, and no positive cases of Circumferential Resection Margin (CRM) or Distal Resection Margin (DRM) were detected in either group. The number of lymph nodes found in surgical specimens did not change significantly between the two groups (P = 0.391). In the subgroup analysis, however, more lymph nodes were detected in female patients undergoing taTME than in male patients (P = 0.028). The ISR group took less time to remove the drainage tubes (P = 0.013) and the same results were obtained in both groups of male patients in the subgroup analysis (P = 0.011). There were no statistically significant differences in time to start liquid diet, time to remove catheters, time to start flatus, time to begin ambulation, postoperative hospital stay, and readmission within 30 days after surgery between the two groups (P > 0.05). However, female patients in the taTME group were initiated ambulation earlier than males in the subgroup analysis (P = 0.034). The difference was insignificant in the occurrence of postoperative complications between the two groups (P > 0.05).

Conclusion

taTME is safe and feasible for the treatment of overweight patients with low rectal cancer.

From Dukes-MAC Staging System to Molecular Classification: Evolving Concepts in Colorectal Cancer

This historical review aimed to summarize the main changes that colorectal carcinoma (CRC) staging systems suffered over time, starting from the creation of the classical Duke’s classification, modified Astler–Coller staging, internationally used TNM (T—primary tumor, N—regional lymph nodes’ status, M—distant metastases) staging system, and ending with molecular classifications and epithelial–mesenchymal transition (EMT) concept. Besides currently used staging parameters, this paper briefly presents the author’s contribution in creating an immunohistochemical (IHC)-based molecular classification of CRC. It refers to the identification of three molecular groups of CRCs (epithelial, mesenchymal and hybrid) based on the IHC markers E-cadherin, β-catenin, maspin, and vimentin. Maspin is a novel IHC antibody helpful for tumor budding assessment, which role depends on its subcellular localization (cytoplasm vs. nuclei). The long road of updating the staging criteria for CRC has not come to an end. The newest prognostic biomarkers, aimed to be included in the molecular classifications, exert predictive roles, and become more and more important for targeted therapy decisions.

Artificial Intelligence-Based Total Mesorectal Excision Plane Navigation in Laparoscopic Colorectal Surgery

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.

CONCLUSION AND FUTURE DIRECTIONS

We successfully developed a total mesorectal excision plane image-guided navigation system based on an areolar tissue segmentation approach with high accuracy. This may aid surgeons in recognizing the total mesorectal excision plane for dissection.

Initial experience of Chinese surgical robot "Micro Hand S″ assisted versus open and laparoscopic total mesorectal excision for rectal cancer: Short-term outcomes in a single center

BACKGROUND

A Chinese surgical robot, Micro Hand S, was introduced for clinical use as a novel robotic platform. This study aimed to comprehensively compare the early experience of the Micro Hand S robot-assisted total mesorectal excision (TME) with conventional approaches.

METHODS

Between May 2017 and April 2018, 99 consecutive patients who underwent open, laparoscopic and Micro Hand S robot-assisted TME (O-/L-/RTME) for rectal cancer were included. Clinical and pathological outcomes were retrospectively analyzed. Surgical success as the primary endpoint was defined as the absence of (i) conversion, (ii) incomplete TME, (iii) involved circumferential and distal resection margins (CRM/DRM), (iv) severe complications.

RESULTS

The rate of surgical success was similar (89.7 vs. 86.4 vs. 84.6%, p = 0.851) in the three groups and the respective incidences were as follows: conversion (not applicable, 4.5 vs. 2.3%, p = 1.000), incomplete TME (6.9 vs. 6.8 vs. 3.8%, p = 0.980), involved CRM/DRM (0 vs. 2.3 vs. 3.8%, p = 0.592), severe complications (3.4 vs. 4.5 vs. 7.7%, p = 0.844). Compared with open and laparoscopic surgery, the robotic surgery was associated with longer operative time, less blood loss, earlier first flatus time and liquid intake time, and shorter length of hospital stay (p < 0.05).

CONCLUSIONS

The Micro Hand S assisted TME is safe and feasible, showing comparable outcomes than conventional approaches, with superiority in blood loss, recovery of bowel function, length of hospital stay, but with increased operative time.

T stage-dependent lymph node and distant metastasis and the accuracy of lymph node assessment in rectal cancer

Objective

To analyze data obtained in a representative number of patients with primary rectal cancer with respect to lymph node diagnostics and related tumor stages.

Methods

In pT2-, pT3-, and pT4 rectal cancer lesions, the impact of investigated lymph nodes on the frequency of pN+ status, the cumulative risk of metachronous distant metastases, and overall survival was studied by means of a prospective multicenter observational study over a defined period of time.

Results

From 2000 to 2011, the proportion of surgical specimens with ≥ 12 investigated lymph nodes increased significantly, from 73.6% to 93.2% (p < 0.001; the number of investigated lymph nodes from 16.2 to 20.8; p < 0.001). Despite this, the percentage of pN+ rectal cancer lesions varied only non-significantly (39.9% to 45.9%; p = 0.130; median, 44.1%). For pT2-, pT3-, and pT4 rectal cancer lesions, there was an increasing proportion of pN+ findings correlating significantly with the number of investigated lymph nodes up to n = 12 investigated lymph nodes. Only in pT3 rectal cancer was there a significant increase in pN+ findings in case of > 12 lymph nodes (p = 0.001), but not in pT2 (p = 0.655) and pT4 cancer lesions (p = 0.256). For pT3pN0cM0 rectal cancer, the risk of metachronous distant metastases and overall survival did not depend on the number of investigated lymph nodes.

Conclusion

In rectal cancer, at least n = 12 lymph nodes are to be minimally investigated. The investigation of fewer lymph nodes is associated with a higher risk of false-negative pN0 findings. In particular, in pT3 rectal cancer, the investigation of more than 12 lymph nodes lowers the risk of false-negative pN0 findings. An upstaging effect by the investigation of a possibly maximal number of lymph nodes could not be detected.

SP rTaTME: initial clinical experience with single-port robotic transanal total mesorectal excision (SP rTaTME)

BACKGROUND

The technical difficulty and steep learning curve of transanal total mesorectal excision (taTME) has limited widespread adoption. The single-port (SP) daVinci robot is designed to facilitate single-incision and natural-orifice transluminal endoscopic surgery (NOTES). This paper describes the first clinical experience of single-port robotic taTME (SP rTaTME).

METHODS

This was a prospective study on consecutive patients with rectal cancer who underwent SP rTaTME proctosigmoidectomy with handsewn coloanal anastomosis in December 2018 and January 2019. The primary outcome was technical feasibility of the procedure. The secondary outcomes include blood loss, intraoperative complications, length of hospital stay, quality of the TME specimen, short- and long-term morbidity and mortality, as well as short-term oncologic follow -up.

RESULTS

There were two patients, a 48-year-old male and a 38-year-old female. Both operations were completed successfully without complications or conversion. Estimated blood loss was 200 mL and 130 mL. In both cases the TME was completed transanally using the SP robot. In the first patient, the abdominal portion was completed through an abdominal single-incision; in the second patient the operation was entirely performed transanally as a pure NOTES procedure. In both cases, the final pathology report showed a complete TME with negative margins. Patients were discharged on postoperative day 3 and 4,respectively. There was no long-term morbidity or mortality.

CONCLUSIONS

SP rTaTME is feasible and can be safely performed. It provides excellent optics and dexterity to work in a limited space. Future studies are required to further define the safety profile and the ultimate utility of the SP robot for taTME.

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.

The prognostic role of tissue TLR2 and TLR4 in colorectal cancer

Colorectal cancer (CRC), the second most common cancer globally, resulted in 881,000 deaths in 2018. Toll-like receptors (TLRs) are crucial to detecting pathogen invasion and inducing the host’s immune response. This study aimed to explore the prognostic value of TLR2 and TLR4 tumor expressions in colorectal cancer patients. We studied the immunohistochemical expressions of TLR2 and TLR4 using tissue microarray specimens from 825 patients undergoing surgery in the Department of Surgery, Helsinki University Hospital, between 1982 and 2002. We assessed the relationships between TLR2 and TLR4 expressions and clinicopathological variables and patient survival. We generated survival curves using the Kaplan-Meier method, determining significance with the log-rank test. Among patients with lymph node–positive disease and no distant metastases (Dukes C), a strong TLR2 immunoactivity associated with a better prognosis (p < 0.001). Among patients with local Dukes B disease, a strong TLR4 immunoactivity associated with a worse disease-specific survival (DSS; p = 0.017). In the multivariate survival analysis, moderate TLR4 immunoactivity compared with strong TLR4 immunoactivity (hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.49–0.89, p = 0.007) served as an independent prognostic factor. In the multivariate analysis for the Dukes subgroups, moderate TLR2 immunoactivity (HR 2.63, 95% CI 1.56–4.44, p < 0.001) compared with strong TLR2 immunoactivity served as an independent negative prognostic factor in the Dukes C subgroup. TLR2 and TLR4 might be new prognostic factors to indicate which CRC patients require adjuvant therapy and which could spare from an unnecessary follow-up, but further investigations are needed.

Laparoscopic Versus Open Resection for Rectal Cancer: A Noninferiority Meta-analysis of Quality of Surgical Resection Outcomes

OBJECTIVE

To determine whether laparoscopic surgery is noninferior to open surgery for rectal cancer in terms of quality of surgical resection outcomes.

BACKGROUND

Randomized clinical trials (RCTs) have evaluated the oncologic safety of laparoscopic versus open surgery for rectal cancer with conflicting results. Prior meta-analyses comparing these operative approaches in terms of quality of surgical resection aimed to demonstrate if one approach was superior. However, this method is not appropriate and potentially misleading when noninferiority RCTs are included.

METHODS

MEDLINE, EMBASE, and Cochrane were searched to identify RCTs comparing these operative approaches. Risk differences (RDs) were pooled using random-effects meta-analyses. One-sided Z tests were used to determine noninferiority. Noninferiority margins (ΔNI) for circumferential resection margin (CRM), plane of mesorectal excision (PME), distal resection margin (DRM), and a composite outcome ("successful resection") were based on the consensus of 58 worldwide experts.

RESULTS

Fourteen RCTs were included. Laparoscopic resection was noninferior compared with open resection for the rate of positive CRM [RD 0.79%, 90% confidence interval (CI) -0.46 to 2.04, ΔNI = 2.33%, PNI = 0.026], incomplete PME (RD 1.16%, 90% CI -0.27 to 2.59, ΔNI = 2.85%, PNI = 0.025), and positive DRM (RD 0.15%, 90% CI -0.58 to 0.87, ΔNI = 1.28%, PNI = 0.005). For the rate of "successful resection" (RD 6.16%, 90% CI 2.30-10.02), the comparison was inconclusive when using the ΔNI generated by experts (ΔNI = 2.71%, PNI = 0.07), although no consensus was achieved for this ΔNI.

CONCLUSIONS

Laparoscopy was noninferior to open surgery for rectal cancer in terms of individual quality of surgical resection outcomes. These findings are concordant with RCTs demonstrating noninferiority for long-term oncologic outcomes between the 2 approaches.

Disease-free Survival and Local Recurrence After Laparoscopic-assisted Resection or Open Resection for Rectal Cancer: The Australasian Laparoscopic Cancer of the Rectum Randomized Clinical Trial

OBJECTIVE

The aim of the study was to determine the efficacy of laparoscopic rectal resection (Lap) versus open laparotomy and rectal resection (Open) for rectal cancer on locoregional recurrence (LRR) and disease-free survival (DFS) at 2 years.

SUMMARY BACKGROUND DATA

Although a Lap approach to colon cancer surgery may offer similar oncological outcomes to Open with potentially less morbidity, this remains to be clearly established for the treatment of rectal cancer.

METHODS

A randomized, multicenter noninferiority phase 3 trial of 475 patients with T1 to T3 rectal adenocarcinoma <15 cm from anal verge, given Lap or Open and followed for a minimum 2 years to assess LRR, DFS, and overall survival (OS).

RESULTS

Secondary endpoint analyses included 450 patients (95%) without metastases at baseline (mean age 64; 34% women) who received Lap (n = 225) or Open (n = 225). Median follow-up was 3.2 years (range: 0.1-5.4 yrs). LRR cumulative incidence at 2 years: Lap 5.4%; Open 3.1% [difference, 2.3%; 95% confidence interval (CI), -1.5% to 6.1%; hazard ratio (HR) 1.7; 95% CI, 0.74-3.9]. DFS at 2 years: Lap 80%; Open 82% (difference, 2.0%; 95% CI, -9.3% to 5.4%; HR for recurrence or death, 1.17; 95% CI, 0.81-1.68; P = 0.41). After adjustment for baseline factors HR = 1.07 (95% CI, 0.7-1.6). OS at 2 years: Lap 94%; Open 93% (difference 0.9%; 95% CI, -3.6% to 5.4%).

CONCLUSIONS

Laparoscopic surgery for rectal cancer did not differ significantly from open surgery in effects on 2-year recurrence or DFS and OS. Confidence intervals included potentially clinically important differences favoring open resection, so that the combination of primary and secondary study endpoints may not support laparoscopic resection of rectal cancer as a routine standard of care and further follow-up is required.

Hybrid abdominal robotic approach with conventional transanal total mesorectal excision (TaTME) for rectal cancer: feasibility and outcomes from a single institution

Total mesorectal excision (TME) is currently recognised as the standard of care for patients with rectal cancer. Complete TME is known to be associated with lower rates of recurrence. Robotic and endoscopic TaTME approaches are reported to offer excellent proximal and distal rectal dissection into the TME plane, however, combining both approaches in a hybrid procedure could potentially optimise visualisation of the dissection plane and confer improved circumferential and distal margin rates. The aim of this study was to analyse the feasibility of a hybrid robotic abdominal approach with conventional TaTME for rectal cancer. Furthermore, pathological and patient outcomes were assessed. A review of prospectively maintained databases was undertaken to assess all patients undergoing robotic TME surgery for rectal tumours from August 2016 to October 2017. Patient demographics, tumour characteristics and outcomes were collated from patient charts and hospital databases. All patients underwent a modified Cecil approach after multidisciplinary team discussion. Eight patients (7 male, 1 female) underwent a combined hybrid approach with a median age of 60 years (range 47-73) and BMI of 29.5 (range 20-39.1) kg/m². Median distance from the anorectal junction (ARJ) was 7.5 (range 4-13) cm. Six patients underwent neoadjuvant treatment with chemoradiotherapy. Patients had a median length of stay (LOS) of 9 (range 4-33) days. There were no intra-operative complications encountered and no patients required a conversion to an open procedure. Complications included one anastomotic leak and one presacral collection. All patients had a complete TME with RO resection with a median number of lymph nodes harvested was 22 (range 6-37) lymph nodes. This hybrid technique is a feasible, practical and operatively favourable approach to rectal cancer surgery with initial pathological outcomes and complication profile equivalent to other approaches.

The Time Between Chemoradiation and Surgery for Rectal Carcinoma Negatively Influences Mesorectal Excision Quality

Total mesorectal excision quality (TMEq) is a prognostic factor associated with local recurrence in rectal adenocarcinoma. Neoadjuvant chemoradiotherapy (NCRT) reduces the risk of tumor recurrence, but may compromise TMEq. The time between NCRT and surgery (TTS) and how it influences TMEq and tumor control were evaluated. In prospective registry, 236 patients after NCRT and TME were analyzed. NCRT involved radiotherapy with 45 Gy to the pelvis, plus tumor boost dose 5.4 Gy with concurrent 5-fluorouracil infusion. NCRT was followed by TME after 9 weeks on average (median 9.4 ± SD 2.5). TMEq was parametrically analyzed by standard three-grade system. With median follow-up of 47.5 months, 3-year overall survival (OS) was 83.8%, disease-free survival (DFS) was 77.7%, and 6.4% was the rate of local recurrence (LR). TTS was not associated with OS, DFS, or LR. TMEq was found to be associated with LR in univariate analysis, but not in multivariate, where pathological tumor stage and resection margins remained dominant predictors. TMEq was negatively influenced by inferior location of the tumor, longer TTS, higher tumor and nodal stage, presence of tumor perforation, perineural invasion, and close/positive resection margins. Nonetheless, TTS remained a strong predictor of TMEq in multivariate analyses. TTS was proven to be an independent predictor of TMEq. With longer TTS, fewer complete TME with intact mesorectal plane were observed. However, TTS was not associated with survival deterioration or tumor recurrence. These were negatively influenced by other factors interfering with TMEq, especially by pathological tumor stage and resection margins.

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.

St.Gallen consensus on safe implementation of transanal total mesorectal excision

Background

The management of rectal cancer has evolved over the years, including the recent rise of Transanal Total Mesorectal Excision (TaTME). TaTME addresses the limitations created by the bony confines of the pelvis, bulky tumours, and fatty mesorectum, particularly for low rectal cancers. However, guidance is required to ensure safe implementation and to avoid the pitfalls and potential major morbidity encountered by the early adopters of TaTME. We report a broad international consensus statement, which provides a basis for optimal clinical practice.

Methods

Forty international experts were invited to participate based on clinical and academic achievements. The consensus statements were developed using Delphi methodology incorporating three successive rounds. Consensus was defined as agreement by 80% or more of the experts.

Results

A total of 37 colorectal surgeons from 20 countries and 5 continents (Europe, Asia, North and South America, Australasia) contributed to the consensus. Participation to the iterative Delphi rounds was 100%. An expert radiologist, pathologist, and medical oncologist provided recommendations to maximize relevance to current practice. Consensus was obtained on all seven different chapters: patient selection and surgical indication, perioperative management, patient positioning and operating room set up, surgical technique, devices and instruments, pelvic anatomy, TaTME training, and outcomes analysis.

Conclusions

This multidisciplinary consensus statement achieved more than 80% approval and can thus be graded as strong recommendation, yet acknowledging the current lack of high level evidence. It provides the best possible guidance for safe implementation and practice of Transanal Total Mesorectal Excision.

Meta-analysis of the impact of surgical approach on the grade of mesorectal excision in rectal cancer

BACKGROUND

The subspecialization of colorectal surgeons, and improvements in the quality of mesorectal excision have revolutionized rectal cancer surgery. With the increasing use of minimally invasive techniques, the completeness of the mesorectal excision has been questioned. This study aimed to assess the pathological outcomes of open versus laparoscopic rectal resection.

METHODS

A meta-analysis of RCTs was undertaken. The primary endpoint was the adequacy of the mesorectal excision. Secondary endpoints included circumferential resection margin and distance to resection margins.

RESULTS

Four studies were included, reporting on 2319 patients; 972 (41·9 per cent) had open and 1347 (58·1 per cent) had laparoscopic resections. Meta-analysis of adequacy of the mesorectal excision showed a small difference in achieving an intact mesorectum in favour of open surgery (risk ratio (RR) 1·06, 95 per cent c.i. 1·02 to 1·10; P = 0·001). Superficial defects were more common in laparoscopic surgery (RR 0·70, 0·54 to 0·89; P = 0·004). Deep mesorectal defects (RR 0·78, 0·51 to 1·20; P = 0·256), circumferential margin (CRM) positivity (RR 0·85, 0·62 to 1·16; P = 0·310), and distance to radial (mean difference (MD) -0·06, 95 per cent c.i. -0·10 to 0·23; P = 0·443) and distal (MD 0·03, -0·06 to 0·12; P = 0·497) margins were all similar. A complete resection (intact mesorectum, negative CRM and distal margin) was achieved in 350 of 478 patients (73·2 per cent) in the laparoscopic group and 372 of 457 (81·4 per cent) in the open group (risk difference (RD) 8 (95 per cent c.i. 3 to 13) per cent; P = 0·003). However, an acceptable mesorectum (intact or superficial defects only) was present in 1254 of 1308 (95·9 per cent) and 916 of 949 (96·5 per cent) in the laparoscopic and open groups respectively (RD 1 (-1 to 3) per cent; P = 0·263).

CONCLUSION

Small differences in mesorectal quality were evident between open and laparoscopic rectal resections. This may be attributable to use of laparoscopic instruments; however, to date minor defects have not affected oncological outcomes.

Simple instruments facilitating achievement of transanal total mesorectal excision in male patients

AIM

To assess the efficacy of a modified approach with transanal total mesorectal excision (taTME) using simple customized instruments in male patients with low rectal cancer.

METHODS

A total of 115 male patients with low rectal cancer from December 2006 to August 2015 were retrospectively studied. All patients had a bulky tumor (tumor diameter ≥ 40 mm). Forty-one patients (group A) underwent a classical approach of transabdominal total mesorectal excision (TME) and transanal intersphincteric resection (ISR), and the other 74 patients (group B) underwent a modified approach with transabdominal TME, transanal ISR, and taTME. Some simple instruments including modified retractors and an anal dilator with a papilionaceous fixture were used to perform taTME. The operative time, quality of mesorectal excision, circumferential resection margin, local recurrence, and postoperative survival were evaluated.

RESULTS

All 115 patients had successful sphincter preservation. The operative time in group B (240 min, range: 160-330 min) was significantly shorter than that in group A (280 min, range: 200-360 min; P = 0.000). Compared with group A, more complete distal mesorectum and total mesorectum were achieved in group B (100% vs 75.6%, P = 0.000; 90.5% vs 70.7%, P = 0.008, respectively). After 46.1 ± 25.6 mo follow-up, group B had a lower local recurrence rate and higher disease-free survival rate compared with group A, but these differences were not statistically significant (5.4% vs 14.6%, P = 0.093; 79.5% vs 65.1%, P = 0.130).

CONCLUSION

Retrograde taTME with simple customized instruments can achieve high-quality TME, and it might be an effective and economical alternative for male patients with bulky tumors.

Tumour-associated macrophages correlate with microvascular bed extension in colorectal cancer patients

Tumour‐associated macrophages (TAMs) represent pivotal components of tumour microenvironment promoting angiogenesis, tumour progression and invasion. In colorectal cancer (CRC), there are no conclusive data about the role of TAMs in angiogenesis‐mediated tumour progression. In this study, we aimed to evaluate a correlation between TAMs, TAM immunostained area (TAMIA) microvascular density (MVD), endothelial area (EA) and cancer cells positive to VEGF‐A (CCP‐VEGF‐A) in primary tumour tissue of locally advanced CRC patients undergone to radical surgery. A series of 76 patients with CRC were selected and evaluated by immunohistochemistry and image analysis. An anti‐CD68 antibody was employed to assess TAMs and TAMIA expression, an anti‐CD34 antibody was utilized to detect MVD and EA expression, whereas an anti‐VEGF‐A antibody was used to detect CCP‐VEGF‐A; then, tumour sections were evaluated by image analysis methods. The mean ± S.D. of TAMs, MVD and CCP‐VEGF‐A was 65.58 ± 21.14, 28.53 ± 7.75 and 63% ± 37%, respectively; the mean ± S.D. of TAMIA and EA was 438.37 ± 124.14μ² and 186.73 ± 67.22μ², respectively. A significant correlation was found between TAMs, TAMIA, MVD and EA each other (r ranging from 0.69 to 0.84; P ranging from 0.000 to 0.004). The high level of expression of TAMs and TAMIA in tumour tissue and the significant correlation with both MVD and EA illustrate that TAMs could represent a marker that plays an important role in promoting angiogenesis‐mediated CRC. In this context, novel agents killing TAMs might be evaluated in clinical trials as a new anti‐angiogenic approach.

Mast cells positive to tryptase and tumour-associated macrophages correlate with angiogenesis in locally advanced colorectal cancer patients undergone to surgery

OBJECTIVE

The density of mast cells positive to tryptase (MCDPT) and tumor-associated macrophages (TAMs) were evaluated in a series of 87 patients with stage B and C colorectal cancer who had undergone radical surgery.

METHODS

MCDPT, TAMs, microvascular density (MVD), endothelial area (EA) and CD8(+) tumor infiltrating lymphocytes (CD8(+) TILs) were evaluated in tumor tissue samples by immunohistochemistry and image analysis. Each of the above parameters was correlated with the others and with the main clinico-pathological features.

RESULTS

A significant correlation between MCDPT, TAMs, MVD and EA was found by Pearson t-test analysis. With special references to the clinico-pathological features a minimal correlation using univariate analysis was found but it was not retained at multivariate analysis.

CONCLUSIONS

Our data suggest that MCDPT and TAMs are linked in the tumor microenvironment and play a role in CRC angiogenesis in a synergistic manner. The assessment of the combination MCDPT and TAMs could be evaluated as a target of novel anti-angiogenic therapies in colorectal cancer patients.

Laparoscopic Colorectal Cancer Resection in High-Volume Surgical Centers: Long-Term Outcomes from the LAPCOLON Group Trial

BACKGROUND

Strong evidence has confirmed the benefit of laparoscopy in colorectal cancer resection but remains a challenging procedure. It is not clear that such promising results in selected patients translate into a favorable risk-benefit balance in real practice. We conducted a multicenter national observational registry to assess operative and oncologic long-term outcomes following laparoscopic colorectal cancer resection.

METHODS

All patients with laparoscopic colorectal cancer resection between 2001 and 2004 were included. Data were extracted from the prospective Italian national database of 10 high-volume centers (≥40 colorectal cancer laparoscopic resections per year). Surgical technique and follow-up were standardized. Survivals were analyzed by Kaplan-Meier method.

RESULTS

We reported 1832 patients with colon (58.5%) and rectal cancer (41.5%). TNM stage was 0-I-II in 1044 patients (57%) and III-IV in 788 patients (43%). Surgery included a totally laparoscopic procedure in 1820 patients (99.3%). Conversion was 10.5%. Postoperative morbidity and 30-day mortality rates were 17 and 1.2%, respectively. Clinical anastomotic leakage rate was 8.3% (n=152). R0 resection was 95%. With a median follow-up of 54.2 months, cancer recurrence rate was 13.3%. At 5 years, cancer-free survival was 86.7%. Upon multivariate analysis, age (P=0.001) and TNM stage (P<0.001) were associated with cancer-free survival. Predictive factors of cancer recurrence were gender (P=0.029) and TNM stage (P<0.001).

CONCLUSIONS

In high-volume centers and non-selective patients, laparoscopic colorectal resection for cancer achieves good operative results with satisfactory long-term oncologic results. Even in the laparoscopy era, age, gender, and TNM stage remain the most powerful predictor of oncologic outcomes.

Which Patients With Rectal Cancer Do Not Need Radiotherapy?

According to current guidelines, the standard treatment for locally advanced rectal cancer patients is preoperative (chemo)radiotherapy followed by total mesorectal excision surgery and adjuvant chemotherapy. Improvements in surgical techniques, imaging modalities, chemotherapy regimens, and radiotherapy delivery have reduced local recurrence rates to less than 10%. The current challenge in rectal cancer treatment lies in the prevention of distant metastases, which still occur in more than 25% of the patients. The decrease in local recurrence rates, the need for more effective systemic treatments, and the increased awareness of treatment-induced toxicity raise the question as to whether a more selective use of radiotherapy is advocated.

Transanal total mesorectal excision in rectal cancer: why, how and when

Down-to-up total mesorectal excision (TME) or transanal TME (taTME) has gained worldwide popularity. taTME is one of the most promising innovations of the last years in the field of gastrointestinal surgery. Due to the better view of the dissection planes even in difficult patients (i.e., narrow pelvis or low rectal cancer), taTME seems to achieve both better TME quality reducing the rate of incomplete TME and lower rates of positive circumferential resection margins. taTME has overall morbidity and anastomotic leak rates comparable with the up-to-down TME. Mid-term results of taTME seems to be comparable with those of the up-to-down approach but definitive conclusions cannot be drawn since the short follow-up and small cohort of patients of the present studies.

Quality assurance in MR image guided adaptive brachytherapy for cervical cancer: Final results of the EMBRACE study dummy run

PURPOSE

Upfront quality assurance (QA) is considered essential when starting a multicenter clinical trial in radiotherapy. Despite the long experience gained for external beam radiotherapy (EBRT) trials, there are only limited audit QA methods for brachytherapy (BT) and none include the specific aspects of image guided adaptive brachytherapy (IGABT).

METHODS AND MATERIALS

EMBRACE is a prospective multicenter trial aiming to assess the impact of (MRI)-based IGABT in locally advanced cervical cancer. An EMBRACE dummy run was designed to identify sources and magnitude of uncertainties and errors considered important for the evaluation of clinical, and dosimetric parameters and their relation to outcome. Contouring, treatment planning and dose reporting was evaluated and scored with a categorical scale of 1-10. Active feedback to centers was provided to improve protocol compliance and reporting. A second dummy run was required in case of major deviations (score <7) for any item.

RESULTS

Overall 27/30 centers passed the dummy run. 16 centers had to repeat the dummy run in order to clarify major inconsistencies to the protocol. The most pronounced variations were related to contouring for both EBRT and BT. Centers with experience in IGABT (>30 cases) had better performance as compared to centers with limited experience.

CONCLUSION

The comprehensive dummy run designed for the EMBRACE trial has been a feasible tool for QA in IGABT of cervix cancer. It should be considered for future IGABT trials and could serve as the basis for continuous quality checks for brachytherapy centers.

Transanal total mesorectal excision (taTME) for cancer located in the lower rectum: short- and mid-term results

BACKGROUND

Laparoscopic trans-abdominal total mesorectal excision is technically demanding. Transanal Total Mesorectal Excision (taTME) is a new technique which seems to provide technical advantages. This study describes the results of taTME in a consecutive series of patients with low rectal cancer.

METHODS

From January 2012 to December 2013, a consecutive series of 26 patients with low rectal cancer underwent laparoscopic taTME with coloanal anastomosis. cT4 or Type II-III rectal cancer (according to Rullier's classification) were contraindications to taTME. After anal sleeve mucosectomy, the rectal wall was transected at the ano-rectal junction. A single-access multichannel port was inserted in the anal canal. taTME was performed from down to up until the sacral promontory posteriorly and the Pouch of Douglas anteriorly were reached. A laparoscopic trans-abdominal approach was used to complete the left colon mobilization.

RESULTS

Sixteen patients (61.5%) were male. The mean distance of the rectal cancer from the anal verge was 4.4 cm (range 3-6). Nineteen patients (73.1%) received long-course neoadjuvant radiotherapy. At final pathology, resection margins were negative in all the patients: the mean distal and radial resection margins were 19 mm and 11.2 mm, respectively. TME was complete in 23 patients (88.5%) and nearly complete in three. Postoperative mortality was 3.8%. The overall morbidity rate was 26.9% (7 patients): two patients (7.7%) had an anastomotic leakage (Dindo I-d). After a mean follow up of 23 months, no patients have developed a local recurrence.

CONCLUSIONS

laparoscopic taTME allow wide resection margins and good quality TME.

Predicting the pathological features of the mesorectum before the laparoscopic approach to rectal cancer

Pelvic anatomy and tumour features play a role in the difficulty of the laparoscopic approach to total mesorectal excision in rectal cancer. The aim of the study was to analyse whether these characteristics also influence the quality of the surgical specimen. We performed a prospective study in consecutive patients with rectal cancer located less than 12 cm from the anal verge who underwent laparoscopic surgery between January 2010 and July 2013. Exclusion criteria were T1 and T4 tumours, abdominoperineal resections, obstructive and perforated tumours, or any major contraindication for laparoscopic surgery. Dependent variables were the circumferential resection margin (CMR) and the quality of the mesorectum. Sixty-four patients underwent laparoscopic sphincter-preserving total mesorectal excision. Resection was complete in 79.1% of specimens and CMR was positive in 9.7%. Univariate analysis showed tumour depth (T status) (P = 0.04) and promontorium-subsacrum angle (P = 0.02) independently predicted CRM (circumferential resection margin) positivity. Tumour depth (P < 0.05) and promontorium-subsacrum axis (P < 0.05) independently predicted mesorectum quality. Multivariate analysis identified the promontorium-subsacrum angle (P = 0.012) as the only independent predictor of CRM. Bony pelvis dimensions influenced the quality of the specimen obtained by laparoscopy. These measurements may be useful to predict which patients will benefit most from laparoscopic surgery and also to select patients in accordance with the learning curve of trainee surgeons.

Correlation between serum tryptase, mast cells positive to tryptase and microvascular density in colo-rectal cancer patients: possible biological-clinical significance

Background

Tryptase is a serin protease stored and released from mast cells (MCs) that plays a role in tumour angiogenesis. In this study we aimed to evaluate serum tryptase levels in colo-rectal cancer (CRC) patients before (STLBS) and after (STLAS) radical surgical resection. We also evaluated mast cell density positive to tryptase (MCDPT) and microvascular density (MVD) in primary tumour tissue.

Methods

A series of 61 patients with stage B and C CRC (according to the Astler and Coller staging system) were selected. Serum blood samples were collected from patients one day before and one day after surgery. Tryptase levels were measured using the UniCAP Tryptase Fluoroenzymeimmunoassay (Pharmacia, Uppsala, Sweden). Tumour sections were immunostained with a primary anti-tryptase antibody (clone AA1; Dako, Glostrup, Denmark) and an anti CD-34 antibody (QB-END 10; Bio-Optica Milan, Italy) by means of immunohistochemistry and then evaluated by image analysis methods.

Results

The mean ± s.d. STLBS and STLAS was 5.63±2.61 µg/L, and 3.39±1.47 µg/L respectively and a significant difference between mean levels was found: p = 0.000 by t-test. The mean ± s.d. of MCDPT and MVD was 8.13±3.28 and 29.16±7.39 respectively. A strong correlation between STLBS and MVD (r = 0.83, p = 0.000); STLBS and MCDPT (r = 0.60, p = 0.003); and MCDPT and MVD (r = 0.73; p = 0.001) was found.

Conclusion

Results demonstrated higher STLBS in CRC patients, indicating an involvement of MC tryptase in CRC angiogenesis. Data also indicated lower STLAS, suggesting the release of tryptase from tumour-infiltrating MCs. Serum tryptase levels may therefore play a role as a novel bio-marker predictive of response to radical surgery. In this context tryptase inhibitors such as Gabexate and Nafamostat Mesilate might be evaluated in adjuvant clinical trials as a new anti-angiogenic approach.

Do t3 rectal cancers always need radiochemotherapy?

The limitation of the traditional method of stratifying patients with rectal cancer for prognosis using magnetic resonance imaging (MRI) and computerised tomography (CT)-TNM staging-is that cT3 tumors comprise the vast majority of rectal cancers. There is a wide variability in outcomes for cT3. Despite this observation, many still advocate routine short course preoperative radiotherapy (SCPRT) or chemoradiation (CRT) for all patients staged as cT3N0 regardless of tumour location, proximity to other structures or extent, despite the fact that advances in imaging with MRI now offer the ability to predict potential outcomes in terms of the risk of local and metastatic recurrence for the individual. Preoperative CRT is designed to reduce local recurrence. The majority of local recurrences historically reflected inadequate quality of the mesorectal resection. Currently, optimal quality-controlled surgery in terms of total mesorectal excision (TME) in the trial setting can be associated with much lower local recurrence rates of less than 10 % whether patients receive radiotherapy or not. Because of the high risk of metastatic disease in selected patients, integrating more active chemotherapy is now attractive. Chemoradiotherapy (CRT) achieves shrinkage and sometimes eradication of tumour-i.e. a pathological complete response (pCR), and reduces local recurrence, but has no impact on overall survival. CRT also increases surgical morbidity and impacts on anorectal, urinary and sexual function with an increased risk of second malignancies. Hence, the predominant aims of CRT have been to shrink/downstage a tumour to allow an R0 resection to be performed, or to increase the chances of performing sphincter-sparing surgery. However, it remains unclear why shrinkage/downstaging is meaningful to a patient unless the tumour is initially borderline resectable or unresectable (i.e. the CRM is threatened) or the aim is to perform a lesser operation (i.e. sphincter-sparing or local excision) or for organ-sparing, i.e. to avoid surgery altogether. If it is important to shrink the cancer-ie there is a predicted threat to the CRM, then CRT is currently the treatment of choice. If the cancer is resectable and the aim is simply to lower the risk of local recurrence and preoperative CRT does not impact on survival, can CRT be omitted in selected cases? The answer is yes-with the proviso that we are using good quality MRI and the surgeon is performing good quality TME surgery within the mesorectal plane.

Extent and completeness of mesorectal excision evaluated by postoperative magnetic resonance imaging

BACKGROUND

The major advance in rectal cancer management over the past 20 years has been the standardization of mesorectal excision. The aim of this study was to determine the prevalence and localization of inadvertent residual mesorectum detected on magnetic resonance imaging (MRI) after rectal cancer surgery.

METHODS

Postoperative T2-weighted MRI of the pelvis was performed on patients following mesorectal excision. A multidisciplinary team radiologist evaluated the images with regard to residual mesorectum and distal margin. Only mesorectum above the level of the anastomosis perpendicular to the bowel was regarded as inadvertent residual mesorectum after partial mesorectal excision. Histopathological records, standardized photographs and clinical records were assessed. The pathology and MRI findings were evaluated independently in a blinded fashion.

RESULTS

MRI-detected residual mesorectum was identified in 54 (39·7 per cent) of 136 patients. There was agreement with the pathology findings in 88 patients (64·7 per cent). Residual mesorectum was more frequent in patients treated with partial mesorectal excision (63 per cent) than those who had total mesorectal excision (36 per cent) or abdominoperineal resection (13 per cent) (P < 0·001). Pathology and MRI findings both showed that the distal resection margin after partial mesorectal excision was less than 5 cm in more than three-quarters of patients, and less than 3 cm in more than one-third.

CONCLUSION

Inadvertent residual mesorectum was commonly found on postoperative MRI, especially after partial mesorectal excision.

Mast cell positivity to tryptase correlates with metastatic lymph nodes in gastrointestinal cancer patients treated surgically

BACKGROUND

Angiogenesis has been found to be a reliable prognostic indicator for several types of malignancies. Tryptase is a serine protease stored in mast cell (MC) granules, which plays a role in tumor angiogenesis. MCs can release tryptase following c-Kit receptor activation.

METHOD

In this study, immunohistochemistry, image analysis methods and clinical aspects were employed in a series of 41 gastrointestinal cancer patients with stage T3-4N2a-bM0 (by the American Joint Committee on Cancer, AJCC, for colorectal cancer, 7th edition) and T3N2-3M0 (by AJCC for gastric cancer, 7th edition) to evaluate the possible correlation between MCs positive to tryptase (MCPT) in tumor tissue and the number of metastatic lymph nodes harvested.

RESULTS

Data demonstrated a positive correlation between MCPT in tumor tissue and the number of metastatic lymph nodes; the validity of these data needs confirmation in larger patient cohorts.

CONCLUSION

This is the first report considering MCPT in tumor tissue as a potential tool for a valid indication of the type of surgical treatment and its radicality, and it might be considered for the prognosis of patients before radical surgical treatment. Our pilot data need confirmation in a larger patient cohort.