Endoscopic submucosal dissection versus transanal endoscopic surgery for the treatment of early rectal tumor: a systematic review and meta-analysis

Comparison of endoscopic submucosal dissection and transanal endoscopic surgery for the treatment of rectal neoplasia: A systematic review and meta-analysis

BACKGROUND AND AIM

Minimally invasive techniques offer alternatives to conventional surgery in the treatment of early-stage colorectal cancer, reducing morbidity. Transanal Endoscopic Microsurgery (TEM) and Transanal Minimally Invasive Surgery (TAMIS) are widely used, while Endoscopic Submucosal Dissection (ESD) is gaining attention for its ability to achieve complete resection with low recurrence rates. This study compares the efficacy and safety of ESD with Transanal Endoscopic Surgery (TES).

METHODS

The authors performed a systematic review and meta-analysis of comparative studies involving patients with endoscopically resectable rectal lesions. Electronic searches were conducted in MEDLINE, EMBASE, Cochrane, and LILACS. Outcomes included recurrence rate, complete resection, en bloc resection, hospital stay, procedure time, and complication rate.

RESULTS

The analysis included ten observational studies and one Randomized Controlled Trial (RCT) involving 1,094 patients. No significant differences were found in terms of recurrence rate, en bloc resection, R0 resection, and complications between techniques. The RCT showed a shorter procedure time in the TES (RD = 16.6; 95 % CI 8.88 to 24.32; p < 0.0001), whereas observational studies found no significant difference. In addition, observational studies found a shorter hospital stay duration in the ESD (MD = -1.22; 95 % CI -2.11 to -0.33; I2 = 82 %; p < 0.007), while the RCT found no difference.

CONCLUSION

ESD and TES are safe and effective for the treatment of early-stage rectal tumors. Rates of local recurrence, block resection, R0 resection, complications, and procedure time were similar. However, the RCT showed a shorter procedure time with TES, while observational studies showed a shorter hospital stay with ESD.

Early Rectal Cancer: Advances in Diagnosis and Management Strategies

Colorectal cancer (CRC) is the second most prevalent cause of cancer-related death and the third most common cancer globally. Early-stage rectal cancer is defined by lesions confined to the bowel wall, without extension beyond the submucosa in T1 or the muscularis propria in T2, with no indication of lymph node involvement or distant metastasis. The gold standard for managing rectal cancer is total mesorectal excision (TME); however, it is linked to considerable morbidities and impaired quality of life. There is a growing interest in local resection and non-operative treatment of early RC for organ preservation. Local resection options include three types of transanal endoscopic surgery (TES): transanal endoscopic microsurgery (TEM), transanal endoscopic operations (TEO), and transanal minimally invasive surgery (TAMIS), while endoscopic resection includes endoscopic mucosal resection (EMR), underwater endoscopic mucosal resection (UEMR), and endoscopic submucosal dissection (ESD). Although the oncological outcome of local resection of early rectal cancer is debated in the current literature, some studies have shown comparable outcomes with radical surgery in selected patients. The use of adjuvant and neoadjuvant chemoradiotherapy in early rectal cancer management is also controversial in the literature, but a number of studies have reported promising outcomes. This review focuses on the available literature regarding diagnosis, staging, and management strategies of early rectal cancer and provides possible recommendations.

Artificial Intelligence to Predict the Risk of Lymph Node Metastasis in T2 Colorectal Cancer

OBJECTIVE

To develop and externally validate an updated artificial intelligence (AI) prediction system for stratifying the risk of lymph node metastasis (LNM) in T2 colorectal cancer (CRC).

BACKGROUND

Recent technical advances allow complete local excision of T2 CRC, traditionally treated with surgical resection. Yet, the widespread adoption of this approach is hampered by the inability to stratify the risk of LNM.

METHODS

Data from patients with pT2 CRC undergoing surgical resection between April 2000 and May 2022 at one Japanese and one Italian center were analyzed. Primary goal was AI system development for accurate LNM prediction. Predictors encompassed 7 variables: age, sex, tumor size, tumor location, lymphovascular invasion, histologic differentiation, and carcinoembryonic antigen level. The tool's discriminating power was assessed through area under the curve, sensitivity, and specificity.

RESULTS

Out of 735 initial patients, 692 were eligible. Training and validation cohorts comprised of 492 and 200 patients, respectively. The AI model displayed an area under the curve of 0.75 in the combined validation data set. Sensitivity for LNM prediction was 97.8%, and specificity was 15.6%. The positive and the negative predictive value were 25.7% and 96%, respectively. The false negative rate was 2.2%, and the false positive was 84.4%.

CONCLUSIONS

Our AI model, based on easily accessible clinical and pathologic variables, moderately predicts LNM in T2 CRC. However, the risk of false negative needs to be considered. The training of the model including more patients across western and eastern centers - differentiating between colon and rectal cancers - may improve its performance and accuracy.

Safety and Efficacy of Endoscopic Submucosal Dissection for Rectal Neoplasms Extending to the Dentate Line: A Systematic Review and Meta-analysis

OBJECTIVE

Endoscopic submucosal dissection (ESD) is a superior, minimally invasive technique compared with other snare-based endoscopic resection techniques for rectal neoplasms extending to the dentate line (RNDLs). However, performing a successful ESD in the anal canal can be challenging due to vascularity and limited scope stability. In this meta-analysis, we aim to evaluate the safety and efficacy of ESD for RNDLs.

METHODS

We performed a comprehensive electronic database search from January 2005 through January 2024 for studies evaluating outcomes of ESD performed for managing RNDLs. Pooled proportions were calculated using random-effect models. Heterogeneity was evaluated using I2 and Q statistics.

RESULTS

Data were extracted from 11 studies comprising 496 patients. The pooled en bloc resection rates were 93.60% (95% CI = 90.70-95.70). The pooled R0 resection rate was 80.60% (95% CI = 70.50-87.80). The pooled recurrence rate was 4.00% (95% CI = 2.40-6.50). There was no evidence of significant heterogeneity calculated using the Q test and I2 statistic. The main adverse events were anal pain, postprocedural bleeding, and anal stricture with pooled rates of 20.20% (95% CI = 14.80-26.90), 8.20% (95% CI = 4.70-14.0), and 3.50% (95% CI = 2.10-5.70), respectively.

CONCLUSIONS

ESD is a safe and effective option for managing RNDLs with a low recurrence rate. Adverse events such as postprocedural perianal pain, postprocedural bleeding, and anal stenosis seem to be more common compared with colorectal ESD done for more proximal lesions. However, these can typically be managed conservatively or with minimally invasive endoscopic techniques.

Evaluation and Management of Malignant Colorectal Polyps

The detection rate of dysplastic colorectal polyps has significantly increased with improved screening programs. Treatment of dysplastic polyps attempt to limit morbidity of a procedure while also considering the risk of occult lymph node metastasis. Therefore, a variety of methods have been developed to predict the rate of lymph node metastasis to help identify the optimal treatment of patients. These include both the endoscopic and pathologic assessment of the lesion. In order to reduce the morbidity of surgery for patients with low-risk lesions, multiple endoscopic therapies have been developed, including endoscopic mucosal resection, endoscopic submucosal dissection, endoscopic intermuscular dissection, and transanal endoscopic surgery.

Robotic transanal minimally invasive surgery (r-TAMIS): perioperative and short-term outcomes for local excision of rectal cancers

BACKGROUND

Transanal minimally invasive surgery (TAMIS) is an advanced technique for excision of early rectal cancers. Robotic TAMIS (r-TAMIS) has been introduced as technical improvement and potential alternative to total mesorectal excision (TME) in early rectal cancers and in frail patients. This study reports the perioperative and short-term oncological outcomes of r-TAMIS for local excision of early-stage rectal cancers.

METHODS

Retrospective analysis of a prospectively collected r-TAMIS database (July 2021-July 2023). Demographics, clinicopathological features, short-term outcomes, recurrences, and survival were investigated.

RESULTS

Twenty patients were included. Median age and body mass index were 69.5 (62.0-77.7) years and 31.0 (21.0-36.5) kg/m2. Male sex was prevalent (n = 12, 60.0%). ASA III accounted for 66.7%. Median distance from anal verge was 7.5 (5.0-11.7) cm. Median operation time was 90.0 (60.0-112.5) minutes. Blood loss was minimal. There were no conversions. Median postoperative stay was 2.0 (1.0-3.0) days. Minor and major complication rates were 25.0% and 0%, respectively. Seventeen (85.0%) patients had an adenocarcinoma whilst three patients had an adenoma. R0 rate was 90.0%. Most tumours were pT1 (55.0%), followed by pT2 (25.0%). One patient (5.0%) had a pT3 tumour. Specimen and tumour maximal median diameter were 51.0 (41.0-62.0) mm and 21.5 (17.2-42.0) mm, respectively. Median specimen area was 193.1 (134.3-323.3) cm2. Median follow-up was 15.5 (10.0-24.0) months. One patient developed local recurrence (5.0%).

CONCLUSIONS

r-TAMIS, with strict postoperative surveillance, is a safe and feasible approach for local excision of early rectal cancer and may have a role in surgically unfit and elderly patients who refuse or cannot undergo TME surgery. Future prospective multicentre large-scale studies are needed to report the long-term oncological outcomes.

Endoscopic submucosal dissection vs transanal endoscopic surgery for rectal tumors: A systematic review and meta-analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) and transanal endoscopic submucosal dissection (TES) are widely employed surgical techniques. However, the comparative efficacy and safety of both remain inconclusive.

AIM

To comprehensively analyze and discern differences in surgical outcomes between ESD and TES.

METHODS

We conducted a systematic search of the electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials, Scopus, and CINAHL from inception till August 2023. We analyzed outcomes including recurrence rate, en bloc resection, R0 resection rate, perforation rate, procedure length, and hospital stay length applying a random-effects inverse-variance model. We assessed publication bias by conducting an Egger's regression test and sensitivity analyses.

RESULTS

We pooled data from 11 studies involving 1013 participants. We found similar recurrence rates, with a pooled odds ratio of 0.545 (95%CI: 0.176-1.687). En bloc resection, R0 resection, and perforation rate values were also similar for both ESD and TES. The pooled analysis for procedure length indicated a mean difference of -4.19 min (95%CI: -22.73 to 14.35), and the hospital stay was on average shorter for ESDs by about 0.789 days (95%CI: -1.671 to 0.093).

CONCLUSION

Both ESD and TES displayed similar efficacy and safety profiles across multiple outcomes. Our findings show that individualized patient and surgeon preferences, alongside specific clinical contexts, can be considered when selecting between these two techniques.

Dilemmas in the Clinical Management of pT1 Colorectal Cancer

Implementation of population-based colorectal cancer screening programs has led to increases in the incidence of pT1 colorectal cancer. These incipient invasive cancers have a very good prognosis and can be treated locally, but more than half of these cases are treated with surgery due to the presence of histological high-risk criteria. These high-risk criteria are suboptimal, with no consensus among clinical guidelines, heterogeneity in definitions and assessment, and poor concordance in evaluation, and recent evidence suggests that some of these criteria considered high risk might not necessarily affect individual prognosis. Current criteria classify most patients as high risk with an indication for additional surgery, but only 2-10.5% have lymph node metastasis, and the residual tumor is present in less than 20%, leading to overtreatment. Patients with pT1 colorectal cancer have excellent disease-free survival, and recent evidence indicates that the type of treatment, whether endoscopic or surgical, does not significantly impact prognosis. As a result, the protective role of surgery is questionable. Moreover, surgery is a more aggressive treatment option, with the potential for higher morbidity and mortality rates. This article presents a comprehensive review of recent evidence on the clinical management of pT1 colorectal cancer. The review analyzes the limitations of histological evaluation, the prognostic implications of histological risk status and the treatment performed, the adverse effects associated with both endoscopic and surgical treatments, and new advances in endoscopic treatment.

[Transanal Tumor Resection: Indication, Surgical Technique and Management of Complications]

Transanal resection procedures are special operations for the minimally invasive treatment of rectal tumours. Apart from benign tumours, this procedure is suitable for the excision of low-risk T1 rectal carcinomas, if these can be completely removed (R0 resection). With stringent patient selection, very good oncological results are achieved. Various international trials are currently evaluating whether local resection procedures are oncologically sufficient if there is a complete or near complete response after neoadjuvant radio-/chemotherapy. Numerous studies have shown that the functional results and the postoperative quality of life after local resection are excellent, especially considering the well-known functional deficits of alternative operations, such as low anterior or abdominoperineal resection.Severe complications are very rare. Most complications, such as urinary retention or subfebrile temperatures, are minor in nature. Suture line dehiscences are usually clinically unremarkable. Major complications comprise significant haemorrhage and the opening of the peritoneal cavity. The latter must be recognized intraoperatively and can usually be managed by primary suture. Infection, abscess formation, rectovaginal fistula, injury of the prostate or even urethra are extremely rare complications.

Post-Surgical Imaging Assessment in Rectal Cancer: Normal Findings and Complications

Rectal cancer (RC) is one of the deadliest malignancies worldwide. Surgery is the most common treatment for RC, performed in 63.2% of patients. The type of surgical approach chosen aims to achieve maximum residual function with the lowest risk of recurrence. The selection is made by a multidisciplinary team that assesses the characteristics of the patient and the tumor. Total mesorectal excision (TME), including both low anterior resection (LAR) and abdominoperineal resection (APR), is still the standard of care for RC. Radical surgery is burdened by a 31% rate of major complications (Clavien-Dindo grade 3-4), such as anastomotic leaks and a risk of a permanent stoma. In recent years, less-invasive techniques, such as local excision, have been tested. These additional procedures could mitigate the morbidity of rectal resection, while providing acceptable oncologic results. The "watch and wait" approach is not a globally accepted model of care but encouraging results on selected groups of patients make it a promising strategy. In this plethora of treatments, the radiologist is called upon to distinguish a physiological from a pathological postoperative finding. The aim of this narrative review is to identify the main post-surgical complications and the most effective imaging techniques.

Long-term results of minimally invasive transanal surgery for rectal tumors in 249 consecutive patients

PURPOSE

To delineate the long-term results of minimally invasive transanal surgery (MITAS) for selected rectal tumors.

METHODS

We analyzed data, retrospectively, on consecutive patients who underwent MITAS between 1995 and 2015, to establish the feasibility, excision quality, and perioperative and oncological outcomes of this procedure.

RESULTS

MITAS was performed on 243 patients. The final histology included 142 cancers, 47 adenomas, and 52 neuroendocrine tumors (NET G1). A positive margin of 1.6% and 100% en bloc resection were achieved. The mean operative time was 27.4 min. Postoperative morbidity occurred in 7% of patients, with 0% mortality. The median follow-up was 100 months (up to ≥ 5 years or until death in 91.8% of patients). Recurrence developed in 2.9% of the patients. The 10-year overall survival rate was 100% for patients with NET G1 and 80.3% for those with cancer. The 5-year DFS was 100% for patients with Tis cancer, 90.6% for those with T1 cancer, and 87.5% for those with T2 or deeper cancers. MITAS for rectal tumors ≥ 3 cm resulted in perioperative and oncologic outcomes equivalent to those for tumors < 3 cm.

CONCLUSION

MITAS is feasible for the local excision (LE) of selected rectal tumors, including tumors ≥ 3 cm. It reduces operative time and secures excision quality and long-term oncological outcomes.

Long-term oncological outcomes after local excision of T1 rectal cancer

BACKGROUND

A growing proportion of patients with early rectal cancer is treated by local excision only. The aim of this study was to evaluate long-term oncological outcomes and the impact of local recurrence on overall survival for surgical local excision in pT1 rectal cancer.

METHODS

Patients who only underwent local excision for pT1 rectal cancer between 1997 and 2014 in two Dutch tertiary referral hospitals were included in this retrospective cohort study. The primary outcome was the local recurrence rate. Secondary outcomes were distant recurrence, overall survival and the impact of local recurrence on overall survival.

RESULTS

A total of 150 patients (mean age 68.5 ± 10.7 years, 57.3% males) were included in the study. Median length of follow-up was 58.9 months (range 6-176 months). Local recurrence occurred in 22.7% (n = 34) of the patients, with a median time to local recurrence of 11.1 months (range 2.3-82.6 months). The vast majority of local recurrences were located in the lumen. Five-year overall survival was 82.0%, and landmark analyses showed that local recurrence significantly impacted overall survival at 6 and 36 months of follow-up (6 months, p = 0.034, 36 months, p = 0.036).

CONCLUSIONS

Local recurrence rates after local excision of early rectal cancer can be substantial and may impact overall survival. Therefore, clinical decision-making should be based on patient- and tumour characteristics and should incorporate patient preferences.

Minimally Invasive Endoscopic and Surgical Management of Rectal Neoplasia

Rectal cancer demonstrates a characteristic natural history in which benign rectal neoplasia precedes malignancy. The worldwide burden of rectal cancer is significant, with rectal cancer accounting for one-third of colorectal cancer cases annually. The importance of early detection and successful management is essential in decreasing its clinical burden. Minimally invasive treatment of rectal neoplasia has evolved over the past several decades, which has led to reduced local recurrence rates and improved survival outcomes. The approach to diagnosis, staging, and selection of appropriate treatment modalities is a multidisciplinary effort combining interventional endoscopy, surgery, and radiology tools. This review examines the currently available minimally invasive endoscopic and surgical management options of rectal neoplasia.

Endoscopic submucosal dissection in tumors extending to the dentate line compared to proximal rectal tumors: a systematic review with meta-analysis

Endoscopic submucosal dissection (ESD) is a validated treatment for early rectal tumors, but whether this therapy is efficient or not for rectal tumors extending to the dentate line (RTDL) remains unclear. We performed a systematic review and meta-analysis to assess the effectiveness and safety of ESD in RTDL compared to non-RTDL. A search in PubMed, Scopus and the Cochrane library up to April 2020 was conducted to identify studies that compared ESD in both localizations (RTDL and non-RTDL), reporting at least one main outcome (en bloc, complete resection, recurrence). Secondary outcomes were adverse event occurrence. Five observational studies including 739 patients with a total of 201 RTDL and 538 non-RTDL were considered. The proportion of female sex (66% vs. 36.9%, P < 0.001) and tumor size [mean difference = 7.75, 95% confidence interval (CI): 3.01-12.49, P = 0.001] were higher in the RTDL group. There were no differences in en bloc resection rates between RTDL and non-RTDL groups [odds ratio (OR): 0.95, 95% CI: 0.50-1.79, P = 0.087]. The complete resection rate was significantly higher in the non-RTDL group (OR: 1.72, 95% CI: 1.18-2.53, P = 0.005, I2 = 0%). However, recurrence rates were comparable (RD: -0.04, 95% CI: -0.07 to 0.00, P = 0.06, I2 = 0%). Concerning adverse events, there were no differences in terms of perforation (OR: 0.9, 95% CI: 0.26-3.08, P = 0.86, I2 = 0%) or delayed bleeding (OR: 0.64, 95% CI: 0.17-2.42, P = 0.51, I2 = 35%). Anal pain rate was 28% (95% CI: 21.4-35.8%). ESD is an effective and safe therapeutic approach for RTDL with comparable recurrence rate to non-RTDL. The lower complete resection rate in RTDL needs to be clarified in studies.

AGA Clinical Practice Update on Surveillance After Pathologically Curative Endoscopic Submucosal Dissection of Early Gastrointestinal Neoplasia in the United States: Commentary

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update was to review the available evidence and provide expert advice regarding surveillance using endoscopy and other relevant modalities after removal of dysplastic lesions and early gastrointestinal cancers with endoscopic submucosal dissection deemed to be pathologically curative. This Clinical Practice Update was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Gastroenterology. This expert commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors, who are advanced endoscopists with high-level expertise in performing endoscopic submucosal dissection to treat dysplasia and early cancers in the luminal gastrointestinal tract.

Transanal endoscopic microsurgical submucosal dissection (TEM-ESD): A novel approach to the local treatment of early rectal cancer

BACKGROUND

Complete local resection is currently the treatment of choice for low-risk early rectal cancer; however, the ideal resection technique for such tumours is still debated. Transanal endoscopic microsurgical submucosal dissection (TEM-ESD) is a new technique which combines the ergonomic advantages of transanal endoscopic microsurgery (TEM) with the minimally invasive approach of endoscopic submucosal dissection (ESD). The aim of our study was to assess the feasibility, safety, and long-term outcomes of TEM-ESD in treating early rectal cancer.

MATERIALS AND METHODS

We retrospectively analysed all cases of rectal adenocarcinomas treated with TEM-ESD in Karlsruhe Municipal Hospital between 2012 and 2019, as well as the perioperative and follow-up data of the patients.

RESULTS

We identified 40 cases (19 low-risk and 21 high-risk carcinomas) matching our criteria. The median size of the lesions was 3.8 cm and the median operating time 48.5 min. En bloc resection was possible in all cases, while histologically complete resection was confirmed in 18 of 19 low-risk tumours and in 30 out of all lesions. The resection was curative in 19 cases. No scarring of the mesorectum was reported during the completion of total mesorectal excision for high-risk tumours. There was only 1 case of local recurrence among patients treated with curative intent, with an overall survival rate of 100% and a disease-free survival rate of 96% at both 2 and 5 years for these patients.

CONCLUSION

TEM-ESD is a safe and feasible therapeutic option for resecting early rectal cancer, offering very good long-term outcomes.

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.

Clinical outcomes of cap-assisted endoscopic resection for small rectal subepithelial tumors

OBJECTIVE

To assess the effectiveness and safety of cap-assisted endoscopic resection and the usefulness of endoscopic ultrasonography (EUS) for managing small rectal subepithelial tumors (SETs).

PATIENTS AND METHODS

Patients with small rectal SETs≤10mm in diameter were enrolled in this study at our hospital from October 2014 to December 2017. First, EUS was performed to evaluate the lesions. Then, cap-assisted endoscopic resection was performed by suctioning the SET into a transparent cap, ligating with a metal snare and then resecting the tumor. The wound was closed using endoclips if necessary.

RESULTS

Forty patients were enrolled in the study. EUS showed lesions originating from muscularis mucosa or submucosa with an average diameter of 5.4×3.1mm. The en bloc resection rate was 85.0% obtained by cap-assisted endoscopic resection, with a mean total procedure time of 17.6min. No immediate perforation happened. Immediate bleeding occurred in five patients; all cases were managed successfully by endoscopy. No delayed bleeding was observed. Pathology examination showed that 70.0% of the lesions were neuroendocrine tumors (G1). One case of recurrence was seen in follow-up; it was managed successfully by endoscopic submucosal dissection. There was no tumor recurrence in a median follow-up period of 41 months in the remaining 39 patients.

CONCLUSIONS

Most small rectal SETs arising from the muscularis mucosa or submucosa are neuroendocrine tumors and require proper treatment. Cap-assisted endoscopic resection is simple, effective and safe for resecting such lesions, and EUS is useful for case screening.

Impact of haptic feedback on applied intracorporeal forces using a novel surgical robotic system-a randomized cross-over study with novices in an experimental setup

Background

Most currently used surgical robots have no force feedback; the next generation displays forces visually. A novel single-port robotic surgical system called FLEXMIN has been developed. Through an outer diameter of 38 mm, two instruments are teleoperated from a surgeon’s control console including true haptic force feedback. One additional channel incorporates a telescope, another is free for special instrument functions.

Methods

This randomized cross-over study analyzed the effect of haptic feedback on the application of intracorporeal forces. In a standardized experiment setup, the subjects had to draw circles with the surgical robot as gently as possible. The applied forces, the required time spans, and predefined error rates were measured.

Results

Without haptic feedback, the maximum forces (median/IQR) were 6.43 N/2.96 N. With haptic feedback, the maximum forces were lower (3.57 N/1.94 N, p < 0.001). Also, the arithmetic means of the force progression (p < 0.001) and their standard deviations (p < 0.001) were lower. Not significant were the shorter durations and lower error rates. No sequence effect of force or duration was detected. No characteristic learning or fatigue curve was observed.

Conclusions

In the experiment setup, the true haptic force feedback can reduce the applied intracorporeal robotic force to one-half when considering the aspects maximum, means, and standard deviation. Other test tasks are needed to validate the influence of force feedback on surgical efficiency and safety.

Transanal minimally invasive surgery (TAMIS) versus endoscopic submucosal dissection (ESD) for resection of non-pedunculated rectal lesions (TRIASSIC study): study protocol of a European multicenter randomised controlled trial

BACKGROUND

In the recent years two innovative approaches have become available for minimally invasive en bloc resections of large non-pedunculated rectal lesions (polyps and early cancers). One is Transanal Minimally Invasive Surgery (TAMIS), the other is Endoscopic Submucosal Dissection (ESD). Both techniques are standard of care, but a direct randomised comparison is lacking. The choice between either of these procedures is dependent on local expertise or availability rather than evidence-based. The European Society for Endoscopy has recommended that a comparison between ESD and local surgical resection is needed to guide decision making for the optimal approach for the removal of large rectal lesions in Western countries. The aim of this study is to directly compare both procedures in a randomised setting with regard to effectiveness, safety and perceived patient burden.

METHODS

Multicenter randomised trial in 15 hospitals in the Netherlands. Patients with non-pedunculated lesions > 2 cm, where the bulk of the lesion is below 15 cm from the anal verge, will be randomised between either a TAMIS or an ESD procedure. Lesions judged to be deeply invasive by an expert panel will be excluded. The primary endpoint is the cumulative local recurrence rate at follow-up rectoscopy at 12 months. Secondary endpoints are: 1) Radical (R0-) resection rate; 2) Perceived burden and quality of life; 3) Cost effectiveness at 12 months; 4) Surgical referral rate at 12 months; 5) Complication rate; 6) Local recurrence rate at 6 months. For this non-inferiority trial, the total sample size of 198 is based on an expected local recurrence rate of 3% in the ESD group, 6% in the TAMIS group and considering a difference of less than 6% to be non-inferior.

DISCUSSION

This is the first European randomised controlled trial comparing the effectiveness and safety of TAMIS and ESD for the en bloc resection of large non-pedunculated rectal lesions. This is important as the detection rate of these adenomas is expected to further increase with the introduction of colorectal screening programs throughout Europe. This study will therefore support an optimal use of healthcare resources in the future.

TRIAL REGISTRATION

Netherlands Trial Register, NL7083 , 06 July 2018.