Transanal endoscopic microsurgery for rectal carcinoids: the largest reported United States experience

Risk Factor Analysis of Lymph Node Metastasis for Rectal Neuroendocrine Tumors: Who Needs a Radical Resection in Rectal Neuroendocrine Tumors Sized 1-2 cm?

BACKGROUND

Rectal neuroendocrine tumors (NETs) have malignant potential, and lymph node (LN) or distant metastases can occur; however, treatment of NETs 1-2 cm in size is controversial.

OBJECTIVE

This study aimed to identify predictive factors for LN metastasis and prognostic factors for recurrence of rectal NETs, especially tumors 1‒2 cm in size.

METHODS

Between October 2004 and November 2020, 453 patients underwent endoscopic or surgical treatment for rectal NETs in Seoul National University Hospital. The data on these patients were prospectively collected in our database and reviewed retrospectively. In cases of local excision, we evaluated LN metastasis with radiologic imaging, including computed tomography or magnetic resonance imaging before treatment and during the follow-up periods.

RESULTS

LN metastasis was observed in 40 patients (8.8%). A higher rate of LN metastasis was observed in larger-sized tumors, advanced T stage, lymphovascular invasion (LVI), perineural invasion (PNI), and high tumor grade. In multivariable analysis, the significant risk factors for LN metastasis were tumor size (1 ≤ size < 2 cm: hazard ratio [HR] 64.07; size ≥2 cm: HR 102.37, p < 0.001) and tumor grade (G2: HR 3.63, p = 0.034; G3: HR 5.09, p = 0.044). In multivariable analysis for tumors 1-2 cm in size, the risk factor for LN metastasis was tumor grade (G2: HR 6.34, p = 0.013).

CONCLUSIONS

Tumor grade and size are important predictive factors for LN metastasis. In NETs 2 cm in size, tumor grade is also important for LN metastasis, and radical resection should be considered.

Trans-anal endoscopic microsurgery for non- adenomatous rectal lesions

BACKGROUND

Trans-anal endoscopic microsurgery (TEM) enables a good visualization of the surgical field and is considered the method of choice for excision of adenomas and early T1 rectal cancer. The rectum and retro-rectal space might be the origin of uncommon neoplasms, benign and aggressive, certain require radical trans-abdominal surgery, while others can be treated by a less aggressive approach. In this study we report outcomes in patients undergoing TEM for rare and non-adenomatous rectal and retro-rectal lesions over a period of 11 years.

AIM

To report outcomes in patients undergoing TEM for rare and non-adenomatous rectal and retro-rectal lesions over a period of 11 years.

METHODS

Between January 2008 to December 2019 a retrospective analysis was completed for all patients who underwent TEM for non-adenomatous rectal lesion or retro-rectal mass in our institution. Patients were discharged once diet was well tolerated and no complications were identified. They were evaluated at 3 wk post operatively, then at 3-mo intervals for the first 2 years and every 6 mo depending on the nature of the final pathology. Clinical examination and rectoscopy were performed during each of the follow-up visits.

RESULTS

Out of 198 patients who underwent TEM during the study period, 18 had non-adenomatous rectal or retro-rectal lesions. Mean age was 47 years. The mean size of the lesions was 2.9 mm, with a mean distance from the anal margin of 7.9 cm. Mean surgical time was 97.8 min. There were no intra-operative neither late post-operative complications. Mean length of stay was 2.5 d. Mean patient follow-up duration was 42 mo.

CONCLUSION

TEM allows for reduced morbidity given its minimally invasive nature. Surgeons should be familiar with the technique but careful patient selection should be considered. It can be used safely for uncommon rectal and selected retro-rectal lesions without compromising outcomes. We believe that it should be reasonably considered as one of the surgical methods when treating rare lesions.

Rectal neuroendocrine neoplasms: what the radiologists should know

Neuroendocrine neoplasms of the rectum (R-NENs) are rare; however, their incidence has increased almost threefold in the last few decades. Imaging of R-NENs includes two primary categories: anatomic/morphologic imaging comprised of endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI), and functional/molecular imaging comprising of planar scintigraphy, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). The management depends on stage, dimension, atypical features, histological grade, and lymphovascular invasion (LVI). Low-risk local R-NENs can be resected endoscopically, and high-risk or locally advanced neoplasms can be treated with radical surgery and lymphadenectomy and/or chemoradiation. The review article focuses on imaging illustrations and discusses applications of different imaging modalities in diagnosing and managing R-NENs.

Long-term clinical outcomes of endoscopic submucosal dissection in rectal neuroendocrine tumors based on resection margin status: a real-world study

BACKGROUND

Endoscopic submucosal dissection (ESD) has been widely adopted in treating rectal neuroendocrine tumors (NETs). However, clinical outcomes in rectal NETs after ESD with different resection margin status remain scanty, particularly in patients with positive resection margins. This study aimed to evaluate the long-term clinical outcomes of ESD in rectal NET based on the resection margin status.

METHODS

This retrospective study included 436 patients diagnosed with rectal NET who had undergone ESD. Clinical data, including age, sex, tumor size, stage, invasion, and the resection margin status, were collected. Further, the patients were assessed for complications, recurrence, distant metastasis, and long-term outcomes.

RESULTS

Among all 436 patients, 395 patients had their primary ESD in our hospital. Complete resection was achieved in 319 patients. Patients who did not achieve complete resection opted for follow-up (n = 73), salvage surgery (n = 1) and salvage ESD (n = 2). Another 41 had their primary ESD in other hospital with incomplete resection and had salvage ESD in our hospital. All 436 patients had a median follow-up period of 61.4 months (range 33.4-125.3 months). During the follow-up period, two patients developed recurrences, while three patients developed metastasis. There were no significant differences in the 5-year progression-free survival and overall survival between patients with incomplete resection opting for follow-up compared to the other two groups (P = 0.5/0.8). However, the complication rates were significantly higher in patients who received salvage ESD.

CONCLUSION

This study demonstrated that positive resection margins have no influence on survival in patients with rectal NET treated using ESD.

Spannungsfeld endoskopische Resektionsverfahren bei GEP-NET // Endoscopic resection for GEP-NET

Neuroendokrine Tumoren des Verdauungstraktes (GEP-NET) sind eine seltene Tumorentität, die häufig als Zufallsbefund diagnostiziert werden. Ein großer Teil dieser Zufallsdiagnosen wird im Rahmen einer endoskopischen Untersuchung gestellt. Während die vollständige Entfernung des Tumors im Sinne einer kurativen chirurgischen Resektion nach onkologischen Kriterien das Standardvorgehen für lokalisierte Tumorerkrankungen ist, kann bei kleinen Tumoren ohne Hinweis und Risiko für eine lymphogene Metastasierung eine endoskopische Abtragung in gleicher Intention erfolgen. Während dies für Magen-, Duodenum- und Rektum-NET der Standard ist, sollten NET des Jejunums und Ileums aufgrund der hohen Metastasierungsrate trotz geringer Tumorgröße regelhaft nicht endoskopisch angegangen werden. Die Grenze für eine endoskopische Resektion ergibt sich sowohl durch die technische Machbarkeit im Sinne des Erreichens einer R0-Resektion, der erwarteten Komplikationen im Sinne von Blutung und Perforationen als auch durch das vermutete Risiko für eine lymphogene Metastasierung. Generell wird eine endoskopische Resektion bei Befunden < 1 cm regelhaft empfohlen, da sowohl die gute technische Machbarkeit als auch das geringe Metastasierungsrisiko für eine endoskopische Resektion sprechen. Bei allen Befunden über 2 cm Größe sind sowohl die technischen Erfolgsaussichten so niedrig als auch das Metastasierungsrisiko so hoch, dass in dieser Situation regelhaft ein chirurgisches Vorgehen erfolgen sollte. Es bleibt somit ein Graubereich bei der Tumorgröße zwischen 1 und 2 cm, wo sowohl endoskopische, aber auch chirurgische Resektionsverfahren sinnvoll eingesetzt werden können. Zunehmend kommen auch gemeinsame Eingriffe im Sinne eines endoskopisch-laparoskopischen Rendezvous-Verfahrens zum Einsatz – insbesondere im Duodenum bieten sich diese Eingriffe an, um eine minimale Resektion mit größtmöglicher R0-Erfolgsrate und niedriger Perforationsrate zu erreichen.

Rectal neuroendocrine tumors: Current advances in management, treatment, and surveillance

Rectal neuroendocrine neoplasms (r-NENs) are considered among the most frequent digestive NENs, together with small bowel NENs. Their incidence has increased over the past few years, and this is probably due to the widespread use of endoscopic screening for colorectal cancer and the advanced endoscopic procedures available nowadays. According to the current European Neuroendocrine Tumor Society (ENETS) guidelines, well-differentiated r-NENs smaller than 10 mm should be endoscopically removed in view of their low risk of local and distant invasion. R-NENs larger than 20 mm are candidates for surgical resection because of their high risk of distant spreading and the involvement of the muscularis propria. There is an area of uncertainty regarding tumors between 10 and 20 mm, in which the metastatic risk is intermediate and the endoscopic treatment can be challenging. Once removed, the indications for surveillance are scarce and poorly codified by international guidelines, therefore in this paper, a possible algorithm is proposed.

Comparison of endoscopic submucosal dissection and transanal endoscopic microsurgery for T1 rectal neuroendocrine tumors: a propensity score-matched study

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) are the most effective endoscopic resection methods for T1 rectal neuroendocrine tumors (NETs). We aimed to compare the efficacy and safety of ESD and TEM for rectal NETs ≤20 mm.

METHODS

Patients with rectal NETs ≤20 mm who underwent ESD or TEM were enrolled in this retrospective observational study. ESD and TEM groups were matched for pathologic tumor size and EMR history. We evaluated between-group differences in R0 resection rate, adverse event rate, procedure time, and hospital stay.

RESULTS

We included 285 patients (ESD = 226, TEM = 59) in the final cohort, with 104 patients in the matched groups (ESD = 52, TEM = 52). The R0 resection rate was significantly higher for TEM (ESD 71.2% vs TEM 92.3%, P = .005). However, the median procedure time (ESD 22 [range, 11-65] vs TEM 35 [17-160] minutes, P < .001) and hospital stay (ESD 2.5 range 1-5] vs TEM 4 [3-8] days, P < .001) were significantly shorter for ESD. In the subgroup analysis of patients divided by tumor size <10 mm (ESD = 218, TEM = 49) and 10 to 20 mm (ESD = 8, TEM = 10)], there was no significant between-group difference in the R0 resection rate (83.5% vs 93.9%, P = .063 and 37.5% vs 80%, P = .145, respectively) or the rate of recurrence.

CONCLUSIONS

Although TEM showed a better overall R0 resection rate for rectal NETs ≤20 mm, ESD could be a viable treatment modality concerning adverse events, procedure time, and hospital stay for rectal NETs <10 mm with similar R0 resection rates in comparison with TEM.

Non-conventional applications for Transanal endoscopic microsurgery. A single centre experience and a systematic review of literature

BACKGROUND

Transanal endoscopic microsurgery (TEM) and Transanal endoscopic operation (TEO) have been initially described for local excision of rectal adenomas and selected cases of rectal carcinomas. In the past decade, however, several new indications raised, and others could raise in the future. The aim of this review was to evaluate, both in the literature and in our personal experience, the use of TEM and TEO for nonconventional applications, different from rectal tumors.

METHODS

We conducted a systematic review of published papers and we selected articles reporting patients who underwent endoscopic surgery for other medical reason than polyp cancer resection, with TEM or TEO. PubMed, MEDLINE, EMBASE and bibliographies of the selected studies were searched for articles in English published up to May 2020 to identify all relevant articles. We excluded articles reporting TEM and TEO used for classical indications. We finally report our experience of non-conventional use of TEO in 5 patients with different diseases.

RESULTS

The research revealed 800 papers and among them we selected 52 articles for a total of 697 patients. Of all patients, only 52 had intraoperative or postoperative complications, with only 10 patients requiring major surgery.

CONCLUSIONS

Our study suggest that TEM and TEO may be valid alternatives to traditional surgery in situations other than its classical indication. These findings can positively impact on the care of patients, who could benefit from less invasive surgical procedures associated with lower morbidity.

Oncological outcomes according to the treatment modality based on the size of rectal neuroendocrine tumors: a single-center retrospective study

BACKGROUND

Owing to an increased number of colonoscopy screenings, the incidence of diagnosed rectal neuroendocrine tumors (NETs) has also increased. Tumor size is one of the most frequently regarded factors when selecting treatment; however, it may not be the determinant prognostic variable. We aimed to evaluate oncological outcomes according to the treatment modality based on the size of rectal NETs.

METHODS

A retrospective analysis was performed on patients who were treated for rectal NETs between March 2000 and January 2016 at the Asan Medical Center, Seoul, Korea. Patients who underwent endoscopic removal, local surgical excision, and radical resection were included. The primary outcome was recurrence-free survival (RFS). Data were specified and analyzed following the 2019 World Health Organization classification (WHO).

RESULTS

A total of 644 patients were categorized under three groups according to the treatment modality used: endoscopic removal (n = 567), surgical local excision (n = 56), and radical resection (n = 21). Of a total of 35 recurrences, 27 were local, whereas eight were distant. The RFS rate did not differ significantly between the treatment groups in the same tumor-size group ([Formula: see text]1 cm group: P = .636, 1-2 cm group: P = .160). For T1 tumors, RFS rate was not different between local excision and radical resection ([Formula: see text]1 cm group: P = .452, 1-2 cm group: P = .700). Depth of invasion, a high Ki-67 index, and margin involvement were confirmed as independent risk factors for recurrence. Among patients treated with endoscopic removal, endoscopic biopsy was a significant factor for worse RFS (P < .001), while tumor size did not affect the RFS.

CONCLUSION

The current guideline recommends treatment options according to tumor size. However, more oncologically important prognostic factors include muscularis propria invasion and a higher Ki-67 index.

Endoscopic full thickness resection vs. transanal endoscopic microsurgery for local treatment of rectal neuroendocrine tumors - a retrospective analysis

PURPOSE

Local treatment of small well-differentiated rectal neuroendocrine tumors (NETs) is recommended by current guidelines. However, although several endoscopic methods have been established, the highest R0 rate is achieved by transanal endoscopic microsurgery (TEM). Since a recently published study about endoscopic full thickness resection (eFTR) showed a R0 resection rate of 100%, the aim of this study was to evaluate both methods (eFTR vs. TEM).

METHODS

We retrospectively analyzed all patients with rectal NET treated either by TEM (1999-2018) or eFTR (2016-2019) in two tertiary centers (University Hospital Wuerzburg and Ulm). We analyzed clinical, procedural, and histopathological outcomes in both groups.

RESULTS

Twenty-eight patients with rectal NET received local treatment (TEM: 13; eFTR: 15). Most tumors were at stage T1a and grade G1 or G2 (in the TEM group two G3 NETs were staged T2 after neoadjuvant chemotherapy). In both groups, similar outcomes for en bloc resection rate, R0 resection rate, tumor size, or specimen size were found. No procedural adverse events were noted. Mean procedure time in the TEM group was 48.9 min and 19.2 min in the eFTR group.

CONCLUSION

eFTR is a convincing method for local treatment of small rectal NETs combining high safety and efficacy with short interventional time.

Endoscopic, transanal, laparoscopic, and transabdominal management of rectal neuroendocrine tumors

Rectal neuroendocrine tumors (RNET) are rare tumors but their prevalence is constantly increasing due to a prolonged survival and rising incidence related to a growing number of colonoscopies and improved knowledge. Their main prognostic determinant is tumor stage. While most RNET are localized, their management should be tailored depending on the presence or absence of the factors predictive of lymph-node metastases including tumor size, endoscopic aspect, T stage, grade and lymphovascular invasion. Endoscopic ultrasonography is the most relevant technique for locoregional assessment. Low-risk RNET can be treated using advanced endoscopic resection techniques or transanal endoscopic microsurgery, in expert centers because they require technicity and experience. Conversely, radical surgery with lymphadenectomy should be proposed in the presence of any pejorative factor. The long-term evolution of RNET remains to be specified, and prospective studies should be conducted in order to determine the relevance of the current management strategies.

Prevalence of metastasis and survival of 788 patients with T1 rectal carcinoid tumors

BACKGROUND AND AIMS

Prevalence of rectal carcinoids is increasing, partly because of increased colorectal cancer screening. Local excision (endoscopic or transanal excision) is usually performed for small (<1-2 cm) rectal carcinoids, but data on clinical outcomes from large population-based U.S. studies are lacking. The aims of this study were to determine the prevalence of metastasis of resected small rectal carcinoid tumors using a large national cancer database and to evaluate the long-term survival of patients after local resection as compared with radical surgery.

METHODS

The Surveillance Epidemiology and End Results database was used to identify 788 patients with rectal T1 carcinoids <2 cm in size. Prevalence of metastases at initial diagnosis and risk factors for metastases were analyzed. Cancer-specific survival (CSS) was calculated.

RESULTS

A total of 727 patients (92.3%) had tumors ≤10 mm in diameter and 61 (7.7%) had tumors 11 to 19 mm. Overall, 12 patients (1.5%) had metastasis at the time of diagnosis with prevalence of 1.1% in lesions ≤10 mm and 6.6% in lesions 11 to 19 mm (P = .01). Survival of patients with T1 rectal carcinoids without metastasis was significantly better than those with metastasis (5-year CSS of 100% vs 78%, P < .001). Of 559 patients with T1N0M0 rectal carcinoids ≤10 mm, 5-year CSS was 100% in both groups who underwent local excision and those who underwent radical surgery.

CONCLUSIONS

Larger T1 rectal carcinoid tumors (11-19 mm) have significantly higher risk of lymph node metastases compared with those ≤10 mm. Survival is worse with metastatic disease. Local therapy is adequate for T1N0M0 rectal carcinoids ≤10 mm in size with excellent long-term outcomes.

Endoscopic submucosal resection with an endoscopic variceal ligation device for the treatment of rectal neuroendocrine tumors

BACKGROUND

Endoscopic resection is recommended for rectal neuroendocrine tumors < 1 cm in diameter; the three techniques (mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device) of endoscopic resection of neuroendocrine tumor were reported; however, the optimal endoscopic technique remains unclear.

PURPOSE

We compared the efficacy and safety of three endoscopic rectal neuroendocrine tumor resection methods.

METHODS

We retrospectively enrolled 52 patients with rectal neuroendocrine tumors treated by endoscopy at Aichi Medical University Hospital and Nagoya City University Hospital between May 2003 and June 2017. We compared clinical outcomes in three groups based on the endoscopic treatment method.

RESULTS

Fifty-two patients underwent endoscopic rectal neuroendocrine tumor treatment (mucosal resection, 14; submucosal dissection, 19; mucosal resection with an endoscopic variceal ligation device, 19). In the endoscopic mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device groups, R0 resection occurred in 50.0, 94.7, and 89.5%, respectively (mucosal resection vs. mucosal resection with variceal ligation device, p < 0.05; mucosal resection vs. submucosal dissection, p < 0.01), while the median procedure times were 6.5, 43, and 6.0 min, respectively (submucosal dissection vs. mucosal resection with variceal ligation device procedure times, p < 0.01; mucosal resection vs. submucosal resection procedure times, p < 0.01). Postoperative bleeding occurred after endoscopic mucosal resection (1/14) and endoscopic submucosal dissection (4/19), but not after endoscopic mucosal resection with a ligation device.

CONCLUSION

Endoscopic mucosal resection with an endoscopic variceal ligation device was a safe, effective treatment for rectal neuroendocrine tumors.

Comparison of Endoscopic Submucosal Dissection for Primary and Recurrent Colorectal Lesions: A Single-Center European Study

INTRODUCTION

Endoscopic submucosal dissection (ESD) is an acknowledged endoscopic technique for the management of early gastrointestinal neoplasia. The clinical experience and the research from the Eastern ESD centers show that experienced endoscopists can successfully treat even the most demanding recurrent colorectal lesions.

AIM

The aim of this study was to analyze the clinical outcomes of the management of recurrent colorectal lesions in comparison with those of primary lesions in the setting of high-volume European center.

METHODS

A retrospective analysis of 298 cases (228 primary lesions and 70 recurrent lesions) performed by a single endoscopist was carried out. Evaluating learning curves for both primary and recurrent lesions, cumulative sum analysis was performed.

RESULTS

Primary lesions had ∼9% higher R0 resection rate (86.84% versus 78.51%). Yet, this difference did not reach statistical significance (P = .091). The presence of recurrent lesion and lengthy procedure (≥150 min) are risks factors of R1 resection, whereas rectal localization of the lesion was associated with lower risk of R1 resection. The cumulative R0 of 80% was achieved at 36th procedure in the primary lesions group, whereas for the recurrent lesions it was reached at 50th procedure (overall 229 procedures).

CONCLUSIONS

Our study underlines the importance of proper experience in ESD before the management of recurrent lesions. Even after the completion of high volume of primary lesions, first recurrent lesions can pose a challenge. Nevertheless, the final outcomes are promising, as the complications do not pose a serious risk to the patients and high R0 resection rate can be achieved in a reasonable timeframe.

Neuroendocrine neoplasms of rectum: A management update

The estimated annual incidence of R-NENs is 1.04 per 100,000 persons although the real incidence may be underestimated, as not all R-NEN are systematically reported in registers. Also the prevalence has increased substantially, reflecting the rising incidence and indolent nature of R-NENs, showing the highest prevalence increase among all site of origin of NENs. The size of the tumor reveals the behavior of R-NENs where the risk for metastatic spread increases for lesions > 10 mm. Applying the WHO 2010 grading system to whole NENs originating in the gastroenteropancreatic system, R-NENs are classified as Well-Differentiated Neuroendocrine Tumors (WD-NET), which contain NET G1 and NET G2, and Poorly-Differentiated Carcinomas (PD-NEC) enclosing only G3 neoplasms for which the term carcinoma is applied. The treatment is endoscopic resection in most cases: conventional polypectomy or endoscopic mucosal resection (EMR) for smaller lesions or endoscopic submucosal resection with a ligation device (ESMR-L), cap-assisted EMR (EMR-C) and endoscopic submucosal dissection (ESD). However it is important to know when the endoscopic treatment is not enough, and surgical treatment is indicated, or when the latter could be unnecessary. For PD-NECs, it has recently been demonstrated that chemoradiotherapy is associated with a similar long-term survival to that obtained with surgery. As well, new targeted-agents chemotherapy may be indicated for metastatic WD-NETs.

Management of complex polyps of the colon and rectum

PUPRPOSE

Benign polyps that are technically challenging and unsafe to remove via polypectomy are known as complex polyps. Concerns regarding safety and completeness of resection dictate they undergo advanced endoscopic techniques, such as endoscopic mucosal resection or surgery. We provide a comprehensive overview of complex polyps and current treatment options.

METHODS

A review of the English literature was conducted to identifyarticles describing the management of complex polyps of the colon and rectum.

RESULTS

Endoscopic mucosal resection is the standard of care for the majority of complex polyps. Only polyps that fail endoscopic mucosal resection or are highly suspicious of invasive cancer but which cannot be removed endoscopically warrant surgery.

CONCLUSION

Several factors influence the treatment of a complex polyp; therefore, there cannot be a "one-size-fitsall" approach. Treatment should be tailored to the lesion's characteristics, the risk of adverse events, and the resources available to the treating physician.

Local surgical excision versus endoscopic resection for rectal carcinoid: A meta-analysis

Purpose: To date, there is not enough evidence concerning the optimal treatment strategy for early rectal carcinoids, we conducted a meta-analysis in order to determine the feasible local treatment for these selected patients. Methods: We searched the studies from the PubMed, Cochrane database, Medline, Ovid, SpringerLink, PMC and Embase between January 2007 and April 2017. Studies of local surgical excision compared with endoscopic resection for rectal carcinoids less than 20mm without adverse features were included. Data were analyzed by using Stata SE 12.0. Results: Seven studies were included in this meta-analysis, with a total of 1056 patients. The data showed that local surgical excision was associated with higher complete resection rate than that of endoscopic resection (OR 5.837, 95%CI 2.048 to 16.632, P=0.001) but consuming longer procedural time (SMD 1.757, 95% CI 1.263 to 2.251, P=0.000). Additionally, incidences of recurrence and en bloc resection rate were comparable between two kinds of resections. The difference of post-operative complications remained unclear. Conclusions: For rectal carcinoids sized 20mm or smaller without adverse features, endoscopic resection might be an efficient treatment, which achieved a comparable oncological safety as local surgical excision.

Local Excision of Rectal Cancer

Local excision (LE) of early-stage rectal cancer avoids the morbidity associated with radical surgery but has historically been associated with inferior oncologic outcomes. Newer techniques, including transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS), have been developed to improve the quality of LE and extend the benefits of LE to tumors in the more proximal rectum. This article provides an overview of conventional LE, TEM, and TAMIS techniques, including indications for their use and pertinent literature on their associated outcomes for rectal cancer.

Transanal endoscopic microsurgery for the treatment of uncommon rectal lesions

INTRODUCTION

Transanal endoscopic microsurgery (TEM) was developed as a less aggressive alternative treatment for rectal lesions (mainly adenomas and adenocarcinomas). However, its use for other rectal lesions has become more frequent, trying to reduce the morbidity associated with more invasive techniques. The aim of this study is to describe our experience in the use of TEM in other rectal lesions.

METHODS

Retrospective and descriptive study including patients operated with TEM (from June 2008 to December 2016) for the treatment of rectal lesions different from adenomas or adenocarcinomas.

RESULTS

Among the 138 patients treated by TEM in our department, 10 patients were operated on for rectal lesions other than adenomas or adenocarcinomas. Rectal lesions were 3neuroendocrine tumours, a neuroendocrine tumour metastasis, a rectal stenosis, a cloacogenic polyp, an endometrioma, a retrorrectal tumour, a presacral abscess and a lesion in the rectovaginal septum. Mean operative time was 72min and postoperative stay was 4.2 days. Only one patient needed a reoperation, due to rectal bleeding.

CONCLUSIONS

TEM could be a useful tool for the treatment of rectal lesions different from adenomas or adenocarcinomas, potentially decreasing the morbidity associated with more aggressive surgical techniques.

Transanal Minimally Invasive Surgery

Transanal endoscopic surgery (TES) techniques encompass a variety of approaches, including transanal endoscopic microsurgery and transanal minimally invasive surgery. These allow a surgeon to perform local excision of rectal lesions with minimal morbidity and the potential to spare the need for proctectomy. As understanding of the long-term outcomes from these procedures has evolved, so have the indications for TES. In this study, we review the development of TES, its early results, and the evolution of new surgical techniques. In addition, we evaluate the most recent research on indications and outcomes in rectal cancer.

Endoscopic submucosal dissection versus transanal local excision for rectal carcinoid: a comparative study

Aim

The aim of this study is to compare the short-term clinical outcomes between endoscopic submucosal dissection and transanal local excision for rectal carcinoid tumors.

Methods

Between 2007 and 2012, 31 patients with rectal carcinoid underwent endoscopic submucosal dissection at our hospital. They were compared with a matched cohort of 23 patients who underwent transanal local excision for rectal carcinoid between 2007 and 2012. Short-term clinical outcomes including surgical parameters, postoperative recovery, and oncologic outcomes were compared between the two groups.

Results

The mean size of tumors was significantly bigger in the transanal local excision group (0.8 ± 0.2 versus 1.1 ± 0.5 cm; P = 0.018). En bloc resection was achieved for 30 patients (97 %) in the endoscopic submucosal dissection group and all the patients in the transanal local excision group. The operation time was longer in the transanal local excision than that in the endoscopic submucosal dissection group (40.0 ± 22.7 min versus 12.2 ± 5.3 min; P < 0.001). Complications in the transanal local excision group were five cases of acute retention of urine. There was no local recurrence or distant metastasis in either group during the follow-up period.

Conclusion

For the treatment of rectal carcinoid tumors with diameter <1 cm, endoscopic submucosal dissection has better short-term clinical outcomes than transanal local excision in terms of faster recovery and possibly a lower morbidity rate. Transanal local excision may be the first therapeutic choice of scar-embedded rectal carcinoid tumors.

Effectiveness of Endoscopic Treatment for Gastrointestinal Neuroendocrine Tumors: A Retrospective Study

Several recent studies have explored efficacy and safety of different endoscopic treatments for gastrointestinal neuroendocrine tumors (GI-NETs). However, there is no definitive consensus regarding the best endoscopic approach for GI-NETs treatment. Therefore, the present study was conducted to investigate the application of various endoscopic techniques for the treatment of GI-NETs according to the previous conclusions and to summarize the optimal endoscopic modalities for GI-NETs. Ninety-eight patients with 100 GI-NETs removed by endoscopic therapies were reviewed. The pathological complete resection rate (PCRR), complication, local recurrence, and factors possibly associated with the pathological complete resection were analyzed. Twenty-two patients were treated by conventional polypectomy (including 6 cold biopsy forceps polypectomy and 16 snare polypectomy with electrocauterization), 41 by endoscopic mucosal resection (EMR), and 35 by endoscopic submucosal dissection (ESD). The PCRRs of conventional polypectomy, EMR, and ESD were 86.4%, 75.6%, and 85.7%, respectively. Sixteen GI-NETs that had a polypoid appearance, with a mean tumor size of 5.2 mm, were removed by snare polypectomy (PCRR 93.8%). The complication rates of conventional polypectomy, EMR, and ESD were 0.0% (0/22), 2.4% (1/41), and 2.9% (1/35), respectively. There were 2 local recurrences after cold biopsy forceps polypectomy treatment and no local recurrences in the EMR and ESD groups (P = 0.049). The results showed that PCRR was only associated with the depth of invasion (P = 0.038). Endoscopic resection of GI-NETs is safe and effective in properly selected patients. For submucosal GI-NETs, ESD was a feasible modality, with a higher PCRR compared with EMR. For ≤5 mm polypoid-like NETs, snare polypectomy with electrocauterization was a simple procedure with a high PCRR.

Full-thickness excision using transanal endoscopic microsurgery for treatment of rectal neuroendocrine tumors

AIM: To assess the efficacy of full-thickness excision using transanal endoscopic microsurgery (TEM) in the treatment of rectal neuroendocrine tumors.

METHODS: We analyzed the data of all rectal neuroendocrine tumor patients who underwent local full-thickness excision using TEM between December 2006 and December 2014 at our department. Data collected included patient demographics, tumor characteristics, operative details, postoperative outcomes, pathologic findings, and follow-ups.

RESULTS: Full-thickness excision using TEM was performed as a primary excision (n = 38) or as complete surgery after incomplete resection by endoscopic polypectomy (n = 21). The mean size of a primary tumor was 0.96 ± 0.21 cm, and the mean distance of the tumor from the anal verge was 8.4 ± 1.4 cm. The mean duration of the operation was 57.6 ± 13.7 min, and the mean blood loss was 13.5 ± 6.6 mL. No minor morbidities, transient fecal incontinence, or wound dehiscence was found. Histopathologically, all tumors showed typical histology without lymphatic or vessel infiltration, and both deep and lateral surgical margins were completely free of tumors. Among 21 cases of complete surgery after endoscopic polypectomy, 9 were histologically shown to have a residual tumor in the specimens obtained by TEM. No additional radical surgery was performed. No recurrence was noted during the median of 3 years’ follow-up.

CONCLUSION: Full-thickness excision using TEM could be a first surgical option for complete removal of upper small rectal neuroendocrine tumors.

Transanal endoscopic resection with peritoneal entry: a word of caution

BACKGROUND

Peritoneal entry during transanal endoscopic microsurgery (TEM) can usually be managed transanally with full-thickness suture closure by experienced operators. The preliminary safety of transanal minimally invasive surgery (TAMIS) has been demonstrated, but the reported experience with upper rectal tumors is limited. The incidence and management of peritoneal entry during transanal endoscopic surgery across various platforms have not been previously evaluated.

METHODS

Retrospective analysis of a prospectively maintained database of all transanal endoscopic resections performed at a single institution between January 2008 and December 2014 was conducted. Cases with and without peritoneal entry were evaluated with respect to transanal platform used, surgical indication, size, location and distance from the anal verge, and incidence of postoperative complications.

RESULTS

A total of 78 transanal endoscopic procedures were performed on 76 patients using the rigid transanal endoscopic operation (TEO, 65.4 %), TEM (26.9 %), and TAMIS platform (7.7 %). The most common surgical indication included endoscopically unresectable adenomas (50 %). The average distance of lesions from the anal verge (AV) was 9.6 cm (range 4-20 cm). Peritoneal entry occurred in 22 cases (28.2 %). Platform used (TAMIS vs. rigid, p < 0.05), mean distance from the AV (p < 0.0001), location along the rectum (p = 0.01), and mean specimen size (p = 0.01) were associated with a higher likelihood of peritoneal entry. All rectal defects associated with peritoneal entry were successfully closed transanally except for two (TEM and TEO) cases that required conversion to laparoscopic low anterior resection and laparoscopic Hartmann's, respectively. There were four TAMIS cases that required conversion to TEO platforms.

CONCLUSION

In this high-risk TEM, TEO, and TAMIS series (one-third of rectal lesions located in the upper rectum), 91 % of all peritoneal entries were managed transanally without increased morbidity. TAMIS for upper rectal lesions was associated with a high risk of complicated peritoneal entry requiring conversion to a rigid platform.

Impact of technology on indications and limitations for transanal surgical removal of rectal neoplasms

Transanal surgery has and continues to be well accepted for local excision of benign rectal disease not amenable to endoscopic resection. More recently, there has been increasing interest in applying transanal surgery to local resection of early malignant disease. In addition, some groups have started utilizing a transanal route in order to accomplish total mesorectal excision (TME) for more advanced rectal malignancies. We aim to review the role of various transanal and endoscopic techniques in the local resection of benign and malignant rectal disease based on published trial data. Preliminary data on the use of transanal platforms to accomplish TME will also be highlighted. For endoscopically unresectable rectal adenomas, transanal surgery remains a widely accepted method with minimal morbidity that avoids the downsides of a major abdomino-pelvic operation. Transanal endoscopic microsurgery and transanal minimally invasive surgery offer improved visualization and magnification, allowing for finer and more precise dissection of more proximal and larger rectal lesions without compromising patient outcome. Some studies have demonstrated efficacy in utilizing transanal platforms in the surgical management of early rectal malignancies in selected patients. There is an overall higher recurrence rate with transanal surgery with the concern that neither chemoradiation nor salvage surgery may compensate for previous approach and correct the inferior outcome. Application of transanal platforms to accomplish transanal TME in a natural orifice fashion are still in their infancy and currently should be considered experimental. The current data demonstrate that transanal surgery remains an excellent option in the surgical management of benign rectal disease. However, care should be used when selecting patients with malignant disease. The application of transanal platforms continues to evolve. While the new uses of transanal platforms in TME for more advanced rectal malignancy are exciting, it is important to remain cognizant and not sacrifice long term survival for short term decrease in morbidity and improved cosmesis.

Endoscopic resection yields reliable outcomes for small rectal neuroendocrine tumors

BACKGROUND AND AIM

We analyzed the characteristics of gastrointestinal neuroendocrine tumors and examined the outcomes and safety of modalities in rectal neuroendocrine tumors.

METHODS

Between 2007 and 2011, a total of 91 patients with gastrointestinal neuroendocrine tumors were retrospectively reviewed in terms of the characteristics of tumors.

RESULTS

Sixty-six patients had rectal neuroendocrine tumors and underwent endoscopic mucosal resection (EMR, n = 29), endoscopic submucosal dissection (ESD, n = 23), or transanal endoscopic microsurgery (TEM, n = 14). The complete resection rate was higher in the ESD group (82.7%) and in the TEM group (100%) compared to the EMR group (65.5%) (P < 0.046). The complication rate was higher in the ESD group (47.8%) than in the EMR group (18.5%) (P = 0.003). No local tumor recurrence was observed in all patients, regardless of the procedure, during the median follow-up period of 21.5 ± 13.5 months.

CONCLUSIONS

ESD achieved a higher complete resection rate than EMR and comparable to TEM. Tumor recurrence was not observed in the endoscopic resection and TEM groups, regardless of the completeness of resection. Small neuroendocrine tumors of the gastrointestinal tract can be managed reliably with both endoscopic resection and TEM.

Which endoscopic treatment is the best for small rectal carcinoid tumors?

The incidence of rectal carcinoids is rising because of the widespread use of screening colonoscopy. Rectal carcinoids detected incidentally are usually in earlier stages at diagnosis. Rectal carcinoids estimated endoscopically as < 10 mm in diameter without atypical features and confined to the submucosal layer can be removed endoscopically. Here, we review the efficacy and safety of various endoscopic treatments for small rectal carcinoid tumors, including conventional polypectomy, endoscopic mucosal resection (EMR), cap-assisted EMR (or aspiration lumpectomy), endoscopic submucosal resection with ligating device, endoscopic submucosal dissection, and transanal endoscopic microsurgery. It is necessary to carefully choose an effective and safe primary resection method for complete histological resection.

Colonic and rectal NET's

Neuroendocrine tumours of the Colon and Rectum are rare but are increasing in incidence as a result of greater investigation with endoscopy and improved histological reporting. Classification with the 2010 WHO TNM staging system as well as grading based on the Ki-67 index has led to improved prognostic assessment. The use of Endoanal Ultrasound has increased the sensitivity of detection of depth of invasion and lymphovascular involvement, which is associated with a poor prognosis. Standard polypectomy has largely been replaced by endoscopic mucosal resection of smaller polyps, although newer techniques such as band ligation or endoscopic submucosal dissection are likely to be associated with less residual disease. The management of advanced disease remains a challenge but new treatments such as Peptide Receptor Targeted therapy and molecular targeted treatments offer hope of improved progression free survival in non-resectable disease.