Transanal endoscopic microsurgery in the treatment of rectal carcinoid tumor

Risk factors for positive resection margins after endoscopic resection for gastrointestinal neuroendocrine tumors

BACKGROUND

In recent years, the incidence of gastrointestinal neuroendocrine tumors (GI-NETs) has remarkably increased due to the widespread use of screening gastrointestinal endoscopy. Currently, the most common treatments are surgery and endoscopic resection. Compared to surgery, endoscopic resection possesses a higher risk of resection margin residues for the treatment of GI-NETs.

METHODS

A total of 315 patients who underwent surgery or endoscopic resection for GI-NETs were included. We analyzed their resection modality (surgery, ESD, EMR), margin status, Preoperative marking and Prognosis.

RESULTS

Among 315 patients included, 175 cases underwent endoscopic resection and 140 cases underwent surgical treatment. A total of 43 (43/175, 24.57%) and 10 (10/140, 7.14%) patients exhibited positive resection margins after endoscopic resection and surgery, respectively. Multivariate regression analysis suggested that no preoperative marking and endoscopic treatment methods were risk factors for resection margin residues. Among the patients with positive margin residues after endoscopic resection, 5 patients underwent the radical surgical resection and 1 patient underwent additional ESD resection. The remaining 37 patients had no recurrence during a median follow-up of 36 months.

CONCLUSIONS

Compared with surgery, endoscopic therapy has a higher margin residual rate. During endoscopic resection, preoperative marking may reduce the rate of lateral margin residues, and endoscopic submucosal dissection may be preferred than endoscopic mucosal resection. Periodical follow-up may be an alternative method for patients with positive margin residues after endoscopic resection.

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.

Diagnosis and Management of Rectal Neuroendocrine Tumors (NETs)

Rectal neuroendocrine tumors (NETs) are rare, with an incidence of 0.17%, but they represent 12% to 27% of all NETs and 20% of gastrointestinal NETs. Although rectal NETs are uncommon tumors, their incidence has increased over the past few years, and this is probably due to the improvement in detection rates made by advanced endoscopic procedures. The biological behavior of rectal NETs may be different: factors predicting the risk of metastases have been identified, such as size and grade of differentiation. The tendency for metastatic diffusion generally depends on the tumor size, muscular and lymphovascular infiltration, and histopathological differentiation. According to the current European Neuroendocrine Tumor Society (ENETS) guidelines, tumors that are smaller than 10 mm and well differentiated are thought to have a low risk of lymphovascular invasion, and they should be completely removed endoscopically. Rectal NETs larger than 20 mm have a higher risk of involvement of muscularis propria and high metastatic risk and are candidates for surgical resection. There is controversy over rectal NETs of intermediate size, 10-19 mm, where the metastatic risk is considered to be 10-15%: assessment of tumors endoscopically and by endoanal ultrasound should guide treatment in these cases towards endoscopic, transanal, or surgical resection.

Relevant risk factors and the prognostic impact of positive resection margins after endoscopic resection of gastrointestinal neuroendocrine tumors

Introduction

Endoscopic resection for the treatment of gastrointestinal neuroendocrine tumors has a risk of resection margin residues. The related risk factors and prognosis of post-endoscopic resection margin residues have not been fully evaluated.

Aim

To investigate the associated risk factors and prognostic impact of resection margin residues after endoscopic resection of gastrointestinal neuroendocrine tumors.

Material and methods

We conducted a retrospective analysis of 129 patients who underwent endoscopic resection for the treatment of gastrointestinal neuroendocrine tumors. Sex, age, location, diameter of tumor, depth of invasion, endoscopic treatment methods, endoscopic ultrasonography (EUS) evaluation, and the work experience of endoscopists were evaluated as potential risk factors. In addition, the prognoses of patients with positive resection margins were analyzed.

Results

A total of 18 (18/129, 14.0%) patients exhibited positive resection margins after endoscopic resection. Among 16 successfully followed-up patients, 1 died due to rupture of pulmonary artery aneurysms, 2 underwent supplementary surgical operations, and 2 underwent additional endoscopic submucosal dissection. The remaining 11 patients were periodically followed up, and no recurrences were found. The results of univariate analysis suggested that endoscopic treatment method, the depth of invasion, and EUS evaluation correlated with positive resection margin. Multivariate regression analysis suggested that the depth of invasion and EUS evaluation were risk factors for resection margin residues.

Conclusions

The depth of invasion and EUS evaluation are independent risk factors for positive resection margins after endoscopic resection. This finding suggests that a greater depth of invasion increases the risk for positive resection margins, while EUS evaluation before resection decreases this risk.

Lymphovascular invasion as a prognostic value in small rectal neuroendocrine tumor treated by local excision: A systematic review and meta-analysis

Because rectal neuroendocrine tumors (NETs) are usually small-sized despite of malignant potential, endoscopic resection techniques are recommended. It is unclear whether the lymphovascular invasion (LVI) in the endoscopic resected specimens of small rectal NETs should be indicated for completion surgery. We performed a systematic review and meta-analysis for the incidence of LVI in small rectal NETs (≤20 mm) treated by endoscopic resection and its prognostic impacts. We searched the relevant literature published before January 2019. A total of 21 publications including 1816 patients were enrolled. Overall prevalence of LVI in small rectal NETs was 21.8%. Immunohistochemical method significantly increased the detection rate of LVI up to 35.8% compared than H&E staining only (13.2%). Tumor size more than 5 mm was a risk factor for LVI in small rectal NET, whereas tumor grade did not influence the risk. The LVI in the endoscopic resected specimens was a risk factor for subsequent lymph node metastasis. Separately analyzed in detail, the vascular invasion had a stronger impact on lymph node metastasis than the lymphatic invasion. The prognosis of endoscopically treated rectal NET with LVI was excellent with only 0.3% of recurrence rate during the 5-year follow-up period. LVI is highly prevalent and a risk factor for lymph node metastasis in the small rectal NETs. Endoscopically treated small rectal NETs had excellent short-term prognoses despite of LVI. Immediate completion radical surgery is not absolutely necessary for the LVI-positive small rectal NETs. However, long-term follow-up is recommended for any delayed recurrence.

Endoscopic treatment of rectal neuroendocrine tumors

The rectum is one of the most frequent location where gastroenteropancreatic neuroendocrine tumors (NETs) are found. With the increasingly widespread availability of colonoscopy screening, the detection rate of rectal NETs has markedly increased, most of which are localized lesions without regional invasion or distant metastasis. Therefore, endoscopic resection is acknowledged as a leading therapeutic approach. Endoscopic mucosal resection, endoscopic submucosal dissection, and transanal endoscopic microsurgery are therapies that have been prevalently applied and technically improved in recent years, which assure increasing complete resection rate and good overall prognosis.

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.

Two Cases of Rectal Neuroendocrine Tumor Resection Combined with Dissection of the Circular Muscle Layer Using the Endoscopic Submucosal Dissection Technique

Generally, lesions of rectal neuroendocrine tumors (NETs) 10 mm or smaller are less malignant and are indicated for endoscopic therapy. However, the vertical margin may remain positive after conventional endoscopic mucosal resection (EMR) because NETs develop in a way similar to submucosal tumors (SMTs). The usefulness of EMR with a ligation device, which is modified EMR, and endoscopic submucosal dissection (ESD) was reported, but no standard treatment has been established. We encountered 2 patients in whom rectal NETs were completely resected by combined dissection and resection of the circular muscle layer using the ESD technique. Case 1 was an 8-mm NET of the lower rectum. Case 2 was NET of the lower rectum treated with additional resection for a positive vertical margin after EMR. In both cases, the circular muscle layer was dissected applying the conventional ESD technique, followed by en bloc resection while conserving the longitudinal muscle layer. No problems occurred in the postoperative course in either case. Rectal NETs are observed in the lower rectum in many cases, and it is less likely that intestinal perforation by endoscopic therapy causes peritonitis. The method employed in these cases, namely combined dissection and resection of the circular muscle layer using the ESD technique, can be performed relatively safely, and it is possible to ensure negativity of the vertical margin. In addition, it may also be useful for additional treatment of cases with a positive vertical margin after EMR.

The implementation of a transanal endoscopic microsurgery programme: initial experience with surgical performance

AIM

Despite transanal endoscopic microsurgery (TEM) being used for over 30 years, there has been slow adoption of this modality in many centres. There remains a paucity of research regarding the learning curve and early performance of surgeons who begin to offer TEM. We sought to determine predictors of longer rates of tumour excision and improvements in operative time in a newly established TEM programme.

METHOD

All patients who underwent TEM at the Ottawa Hospital, Ottawa, Canada, between October 2009 and September 2014 were included. Data were abstracted through a retrospective chart review. The average rate of lesion excision (ARE) was calculated to standardize the operation time by size of the pathological specimen (min/cm³ ), representing a measure of surgical efficiency. Surgical efficiency was plotted using restricted cubic splines. Predictors of higher ARE were determined using multivariable regression.

RESULTS

During the study period 108 patients underwent TEM. ARE was available for 95 patients of mean age 67.2 years. The mean ARE was 18.6 min/cm³ . On adjusting for important covariates, the ARE improved with each additional case until 16 cases were completed. Significant predictors of higher ARE on multivariable analysis were age < 50 years, experience of fewer than five cases, and carcinoid/gastrointestinal stromal tumour or scar histology.

CONCLUSION

Operative efficiency appears to improve as surgeons completed 16 TEM cases. We have identified important factors that result in longer operating time. The study has important implications with regard to surgical training and operative planning for new TEM programmes.

Review article: the investigation and management of rectal neuroendocrine tumours

BACKGROUND

Rectal neuroendocrine tumours (NETs) are increasingly identified at endoscopy possibly as a result of bowel cancer screening programmes.

AIM

To present a review of the literature to aid clinicians in the diagnosis and management of rectal neuroendocrine tumours.

METHODS

A literature search was conducted through MEDLINE using search terms: rectal, rectum, carcinoid, NET, therapy, endoscopy, mucosal resection, submucosal dissection. Relevant articles were identified through manual review with reference lists reviewed for additional articles.

RESULTS

The incidence of rectal neuroendocrine tumours is approximately 1 per 100 000 population per year with the majority (80-90%) being <1 cm and localised to the submucosa. Metastatic disease is infrequent (<20%) with risk factors including size, atypical appearance, grade and depth of invasion. The primary resection modality influences complete resection rates and the need for secondary therapy. A thorough pre-resection diagnostic work up is required for lesions that are at higher risk of invasion and metastasis. Device-assisted endoscopic mucosal resection and endoscopic submucosal dissection are used to resect localised rectal neuroendocrine tumours <2 cm. Transanal surgery is also used to resect localised 1-2 cm rectal neuroendocrine tumours. Oncological surgical resection is used for rectal neuroendocrine tumours that are >2 cm or with invasion and regional disease. The treatment of advanced disease is multimodal.

CONCLUSIONS

The long-term tumour biology of small rectal neuroendocrine tumours remains unclear. There is uncertain impact from bowel cancer screening programmes on rectal neuroendocrine tumour incidence, morbidity and mortality. Referral to neuroendocrine tumour centres for patients with locally advanced disease or metastatic disease is recommended.

Gastrointestinal neuroendocrine tumors: Searching the optimal treatment strategy--A literature review

Neuroendocrine tumors of the gastro-entero-pancreatic system (GEP-NETs) are a heterogeneous group of neoplasms, with different malignant potential and behavior. Many treatment options are available. Surgery should be considered for localized tumors and in some selected cases of metastatic disease. Somatostatin analogs, useful for symptoms control in functioning tumors, are also effective to inhibit tumor progression in specific settings. The multi-TKI sunitinib and of the mTOR-inhibitor everolimus are efficacy for metastatic pancreatic NET (P-NET) treatment. Chemotherapy is generally used in symptomatic and progressive NETs. Peptide receptor radionuclide therapy (PRRT) should be recommended after failure of medical therapy. For tumors confined to the liver ablative techniques should be considered. Nevertheless a shared therapeutic sequence for GEP-NET treatment still does not exist. In this review, we analyzed available data trying to identify the better treatment strategy and to suggest potential therapeutic algorithms distinguishing P-NETs from gastrointestinal NETs (GI-NETs).

Neuroendocrine Rectal Tumors: Main Features and Management

The incidence of neuroendocrine tumors of the rectum has been increasing in the last decades, partly due to improved investigation. They are mostly well-differentiated small tumors with a rather good overall prognosis. In the last few years, some aspects of neuroendocrine tumors have been evolving. In 2010, the World Health Organization proposed a new classification, indicating that these tumors, as a category, should be considered malignant. Afterwards the European Neuroendocrine Tumor Society published their guidelines for the management of colorectal neoplasms. Treatment algorithm is mainly based on tumor size and grading and, in general, well-differentiated rectal tumors <2 cm can be endoscopically resected. Endorectal ultrasound plays a particularly important role by accurately assessing tumor size and depth of invasion prior to resection. There are no specific recommendations on the optimal endoscopic resection method, but data from recent studies suggests that modified endoscopic mucosal resection techniques and endoscopic submucosal dissection have superior complete resection rates.

Circumferential submucosal incision prior to endoscopic mucosal resection provides comparable clinical outcomes to submucosal dissection for well-differentiated neuroendocrine tumors of the rectum

BACKGROUND

Small rectal neuroendocrine tumors (NETs) can be treated with endoscopic resection. Endoscopic submucosal dissection (ESD) has been accepted as a reliable technique, but it is difficult. We evaluated the feasibility and efficacy of precut and endoscopic mucosal resection (CSI-EMR) for rectal NETs compared to ESD.

METHODS

Patients with rectal NETs were enrolled consecutively. ESD or CSI-EMR was performed at operator's discretion. Histological and clinical outcomes were measured and compared between the two treatment modalities.

RESULTS

Thirty-three patients were enrolled in the study. Seventeen NETs were treated by the ESD method and 16 were treated by CSI-EMR. Both groups had similar mean tumor diameters (ESD 7.53 ± 1.94 vs. CSI-EMR 6.63 ± 1.99 mm; p = 0.197). En bloc resection was achieved in 100 % of ESD group and 87.5 % of CSI-EMR group. Lateral margin involvement occurred in one patient in ESD group and two in CSI-EMR group. The histologically complete resection rate was 88.2 % (15 of 17) in the ESD group and 81.2 % (13 of 16) in CSI-EMR group (p = 0.592). One case of perforation occurred in both groups. Delayed bleeding did not occur. None of the measured outcomes were different between the two groups. Operating time was significant shorter in CSI-EMR group than in ESD group (9.69 vs. 20.12 min, respectively; p value = 0.004).

CONCLUSIONS

CSI-EMR results in reliable clinical outcomes for small rectal NETs comparable to those of ESD. CSI-EMR is technically feasible and more time saving.

Resection of multiple rectal carcinoids with transanal endoscopic microsurgery: Case report

Multiple rectal carcinoids are rare. Due to the unreliability of endoscopic polypectomy in treating these submucosal lesions, a laparotomy is usually performed. We present a case report on multiple rectal carcinoids with three carcinoid foci < 10 mm in diameter located in the mid-rectum. Preoperative examination showed the lesions to be confined to the submucosal layer with no perirectal nodal involvement. A transanal endoscopic microsurgery was successfully performed to remove the three lesions with accurate full-thickness resection followed by secured suture closure. The postoperative pathology revealed neuroendocrine tumors G1 (carcinoids) located within the submucosal layer without lymphatic or vessel infiltration. Both the deep and lateral surgical margins were completely free of tumor cells. The patient recovered quickly and uneventfully. No tumor recurrence was observed at the six-month follow-up. For the multiple small rectal carcinoids without muscularis propria or lymphatic invasion, transanal endoscopic microsurgery offers a reliable and efficient alternative approach to traditional laparotomy for select patients, with the added advantages of minimally invasive surgery.

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.

Transanal endoscopic microsurgery: a review

Rectal adenomas and cancers occur frequently. Small adenomas can be removed colonoscopically, whereas larger polyps are removed via conventional transanal excision. Owing to technical difficulties, adenomas of the mid- and upper rectum require radical resection. Transanal endoscopic microsurgery (TEM) was first designed as an alternative treatment for these lesions. However, since its development TEM has been also used for a variety of rectal lesions, including carcinoids, rectal prolapse and diverticula, early stage carcinomas and palliative resection of rectal cancers. The objective of this review is to describe the current status of TEM in the treatment of rectal lesions. Since the 1980s, TEM has advanced substantially. With low recurrence rates, it is the method of choice for resection of endoscopically unresectable adenomas. Some studies have shown benefits to its use in treating early T1 rectal cancers compared with radical surgery in select patients. However, for more advanced rectal cancers TEM should be considered palliative or experimental. This technique has also been shown to be safe for the treatment of other uncommon rectal tumours, such as carcinoids. Transanal endoscopic microsurgery may allow for new strategies in the treatment of rectal pathology where technical limitations of transanal techniques have limited endoluminal surgical innovations.

Endoscopic resection therapies for rectal neuroendocrine tumors: a systematic review and meta-analysis

BACKGROUND AND AIM

Among various endoscopic resection therapies, including conventional endoscopic mucosal resection (EMR) only with a snare after submucosal injection, modified EMR (m-EMR) with other assistant devices such as a ligation band or a suction cap, and endoscopic submucosal dissection (ESD), we aimed to study which is the best choice for rectal neuroendocrine tumors.

METHODS

A broad literature research was performed, and a systematic review and meta-analysis were conducted.

RESULTS

Ten retrospective studies with 650 patients were included. Complete resection rates were significantly higher in the ESD group compared with the EMR group (relative risk [RR] 0.89, 95% confidence interval [CI] [0.79, 0.99]), in the m-EMR group compared with the conventional EMR group (RR 0.72, 95% CI [0.60, 0.86]), and was comparable between the ESD group and the m-EMR group (RR 1.03, 95% CI [0.95, 1.11]). Procedure time was significantly longer in the ESD group than in the EMR group (standard mean differences -1.37, 95% CI [-1.99, -0.75]), but there was no significant difference between that of the m-EMR group and ESD group (standard mean differences -1.50, 95% CI [-3.14, 0.14]). Local recurrence occurred in five cases in the EMR group (5/328) and did not occur in the ESD group (0/209).

CONCLUSIONS

ESD or m-EMR techniques could be applied to rectal neuroendocrine tumors with indications for endoscopic treatment. m-EMR procedures appear to be comparable with ESD in the treatment of rectal neuroendocrine tumors. However, the findings have to be carefully interpreted due to the lower level of evidence.

Prognostic significance of Ki-67 expression in rectal carcinoid tumors

BACKGROUND/AIMS

Rectal carcinoid tumors can be resected with endoscopy, and it is important to assess their prognostic factors. We evaluated the potential of Ki-67 expression as a prognostic factor in rectal carcinoid tumors.

METHODS

We retrospectively reviewed the medical records of 37 patients with rectal carcinoid tumors who got endoscopic resection from January 2001 to January 2011 at Inje University Seoul Paik Hospital. We analyzed their endoscopic and histologic findings, Ki-67 expression, clinical outcome, and prognosis.

RESULTS

The mean age (±SD) of the patients was 56.3±10.7 years, and the male : female ratio was 3.6 : 1. The mean tumor size was 0.5±0.4 cm, 33 patients showed grade 1 tumors (89.2%) and the average Ki-67 expression was 0.7±1.2%. Thirty five patients underwent endoscopic mucosal resection, and two required endoscopic submucosal dissection. Eight patients had positive margins after resection, but no cases of lymphovascular invasion were identified. The median follow-up duration was 21.4±25.4 months, and no recurrences were observed.

CONCLUSIONS

In low grade rectal carcinoid tumors which are lack of central depression on colonoscopy, the expression of a molecular marker of malignant potential, Ki-67, was low. Therefore, endoscopic resection seemed to be a safe and effective treatment for these tumors.

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.

Transanal single-port microsurgery for rectal tumors: minimal invasive surgery under spinal anesthesia

BACKGROUND

Transanal minimally invasive surgery (TAMIS) for rectal tumors has been introduced as an alternative approach to transanal endoscopic microsurgery (TEM). TEM has some limitations, such as the need for special equipment, expensive cost, and steep learning curve. In this study, we address the technical feasibility of TAMIS under spinal anesthesia and its short-term postoperative outcomes.

METHODS

From July 2011 to September 2012, 25 consecutive patients with middle or upper third rectal masses underwent TAMIS. Tumors were located 6-17 cm from the anal verge. After spinal anesthesia, a single-incision laparoscopic surgery port was inserted into the anal canal. With this access, conventional laparoscopic instruments, including a grasper and monopolar electrocautery and suction device, were used to perform the transanal excision. A hook-type monopolar electrocautery or harmonic scalpel was used for dissection. The defect of the rectum was closed by interrupted sutures. Data concerning demographics, details of operative procedure, postoperative pain, and pathologic results were collected prospectively. To evaluate anal sphincter injury, an endoanal ultrasonography and fecal incontinence severity index survey were performed at 3-6 months after the operation.

RESULTS

Of the 25 patients, nine had adenocarcinomas, nine had neuroendocrine tumors, three had tubular adenomas with high-grade dysplasia, three had tubular adenomas, one had a tubulovillous adenoma, and one had a gastrointestinal stromal tumor. The median distance from the tumor mass to the anal verge was 9.0 (range 6-17) cm. The median operative time was 45.0 (range 20-120) min. All patients received TAMIS without conversion to laparoscopic resection. There were no intraoperative complications or postoperative morbidity. The median postoperative hospital stay was 3.0 (range 2-7) days. No sphincter injury was detected by endoanal ultrasonography.

CONCLUSIONS

TAMIS under spinal anesthesia is a safe and feasible technique for resection of middle and upper rectal masses. Spinal anesthesia is adequate for this procedure.

Examining rectal carcinoids in the era of screening colonoscopy: a surveillance, epidemiology, and end results analysis

BACKGROUND

Little is known about the epidemiology of rectal carcinoids in the United States since the implementation of screening colonoscopy.

OBJECTIVE

The goal of this study was to identify epidemiological differences between rectal and small intestinal carcinoids.

DESIGN

This study was retrospective in design.

SETTING

Surveillance, Epidemiology and End Results registry data from 1992 to 2008 were examined.

PATIENTS

Patients with rectal carcinoids included those with carcinoid tumors of the rectum. Patients with small intestinal carcinoids included those with carcinoids in the duodenum, jejunum, or ileum.

MAIN OUTCOME MEASURE

Epidemiological characteristics of rectal carcinoids were identified and compared with small intestinal carcinoids using multiple variable logistic regression.

RESULTS

Patients with rectal carcinoids were more likely to be women (OR, 1.196 (95% CI, 1.090-1.311); p < 0.001). Rectal carcinoids were more common among all minorities, including Asians (OR, 10.063 (95% CI, 8.330-12.157); p < 0.001), blacks (OR, 1.994 (95% CI, 1.770-2.246); p < 0.001), and Hispanics (OR, 2.682 (95% CI, 2.291-3.141), p < 0.001). Patients in the 50- to 59-year age group (OR, 0.752 (95% CI, 0.599-0.944); p = 0.014) were more likely to be diagnosed with rectal carcinoids than those in the 60- to 69-year (OR, 0.481 (95% CI, 0.383-0.605); p < 0.001) and ≥70-year age groups (OR, 0.220 (95% CI, 0.175-0.277); p < 0.001). Rectal carcinoids were more likely to be diagnosed in the screening colonoscopy era among the 50- to 59-year age group (OR, 1.432 (95% CI, 1.082-1.895); p = 0.012). Since the implementation of screening colonoscopy in 2000, the proportion of patients diagnosed with rectal carcinoids has been greater than the proportion diagnosed with small intestinal carcinoids in every year except 2001, and the proportion of patients diagnosed with rectal carcinoids after 2000 has been greater than the proportion diagnosed with small intestinal carcinoids in 12 of 13 Surveillance, Epidemiology, and End Results registry reporting agencies.

CONCLUSIONS

Rectal carcinoids and small intestinal carcinoids are epidemiologically distinct tumors with unique presentations. In the era of screening colonoscopy, rectal carcinoids are the more common tumor.

Surgery for GEP-NETs

Surgery is the only treatment that may cure the patient with gastroentero-pancreatic (GEP) neuroendocrine tumours (NET) and neuroendocrine carcinomas (NEC) and should always be considered as first line treatment if R0/R1 resection can be achieved. The surgical and interventional procedures for GEP-NET are accordingly described below. Life-long follow-up should be performed in almost all patients at a specialized NET center.

Transanal endoscopic microsurgery for rectal tumors: a review

Since its introduction in 1983, transanal endoscopic microsurgery (TEM) has emerged as a safe and effective method to treat rectal lesions including benign tumors, early rectal cancer, and rectal fistulas and strictures. This minimally invasive technique offers the advantages of superior visualization of the lesion and greater access to proximal lesions with lower margin positivity and specimen fragmentation and lower long-term recurrence rates over traditional transanal excision. In addition, over two decades of scientific data support the use of TEM as a viable alternative to radical excision of the rectum with less morbidity, faster recovery, and greater potential cost savings when performed at specialized centers.

Usefulness of endoscopic submucosal dissection for the treatment of rectal carcinoid tumors

BACKGROUND AND AIM

Various techniques of endoscopy have been developed to treat rectal carcinoids. This retrospective study aimed to evaluate the feasibility and efficacy of endoscopic submucosal dissection for the treatment of rectal carcinoids smaller than 10 mm in diameter.

PATIENTS AND METHODS

A total of 18 consecutive patients were enrolled with 20 carcinoid tumors that had the following characteristics: the diagnosis of a rectal carcinoid smaller than 10 mm, no endoscopic evidence of muscularis propria invasion, and no evidence of lymph node or distant metastasis (11 men and seven women; median age, 69 years; median tumor size, 4 mm). Tumors were resected by endoscopic submucosal dissection with a needle knife and a hook knife. After marking, a one-third to one-half circumferential mucosal incision was made, and subsequently, the submucosa under the lesion was exfoliated. After the submucosa under the tumor was exfoliated, the residual mucosa was incised and the tumor was removed. Complete resection, complication rates, and operation time were evaluated.

RESULTS

Complete resection was achieved in all cases (100%) without complications. The mean operation time was 34.2 min, which was acceptable in clinical practice.

CONCLUSION

Endoscopic submucosal dissection with the strategy described above is feasible and efficacious for selected patients with a rectal carcinoid smaller than 10 mm.

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

AIM

Rectal carcinoids are often inadequately resected by snare excision during colonoscopy. Transanal endoscopic microsurgery is a minimally invasive procedure with low morbidity that offers full-thickness excision with a low rate of negative margins. It presents an excellent alternative to radical surgery for mid and proximally located lesions. We report the largest United States (US) experience in the use of transanal endoscopic microsurgery for rectal carcinoids.

METHOD

Data of patients who had undergone transanal endoscopic microsurgery for rectal carcinoids were prospectively collected and retrospectively analyzed. Patient and tumour characteristics, operative and perioperative details, as well as oncological outcomes were reviewed.

RESULTS

Over a 12-year period, 24 patients underwent transanal endoscopic microsurgery for rectal carcinoids. Of these, six (25%) were primary surgical resections and 18 (75%) were performed after incomplete snare excisions during colonoscopy. Three (17%) patients who underwent full-thickness resection after snare excision had residual tumour on histopathological examination. Negative margins were obtained in all cases. No recurrences were noted.

CONCLUSION

Transanal endoscopic microsurgery is effective and safe for the surgical resection of rectal carcinoids<2 cm in diameter, with typical features and located more than 5 cm from the anal verge. Transanal endoscopic microsurgery can be used for primary resection or for resection after incomplete colonoscopic snare excision.

Transanal endoscopic microsurgery: long-term experience, indication expansion, and technical improvements

BACKGROUND

This study aimed to review the authors' 16-year experience with transanal endoscopic microsurgery (TEM). Mortality, morbidity, recurrence rate, and functional outcome were assessed. New indications and technical improvements are presented.

METHODS

From November 1991 to August 2008, 123 patients (72 men and 51 women; median age, 68 years; range, 21-91 years) underwent TEM for excision of 105 adenomas with low- or high-grade dysplasia, 9 invasive adenocarcinomas (5 curative and 4 palliative resections), 2 neuroendocrine tumors, and 2 extramucosal lesions. Five additional patients had excisional biopsies, allowing staging after previous endoscopic resection. Most of the resections were full-thickness rectal resections using electrocautery or, more recently, the Harmonic scalpel. The latest mucosectomies were performed using the endoscopic submucosal dissection (ESD) technique. In addition, nontumoral indications included pelvic abscess (7 patients) and rectal strictures, which were either anastomotic or chemical. Pelvic abscesses were drained transrectally, whereas rectal stenoses were treated by strictureplasty. Foreign object retrieval and collagen plug placement for anal fistulas were performed using TEM in three patients.

RESULTS

No mortality occurred. One intraoperative rectal perforation required conversion to laparotomy. The postoperative complications included one pneumoperitoneum, which was treated medically, and one rectal perforation requiring Hartmann's procedure. In the polyp subgroup, six patients (6/91, 7%) experienced local recurrence. Pelvic abscesses were successfully treated, and stenosis did not recur after strictureplasty. Anorectal manometry showed functional alterations without significant clinical impact.

CONCLUSIONS

The findings showed TEM to be a safe and effective procedure for local excision of rectal lesions with a low recurrence rate and minimal consequences in terms of anorectal function. In addition, TEM proved to be feasible and effective for pelvic abscess drainage and rectal stenosis treatment. New technologies such as the Harmonic scalpel and ESD increase the precision already offered by this approach.

The NANETS consensus guidelines for the diagnosis and management of gastrointestinal neuroendocrine tumors (nets): well-differentiated nets of the distal colon and rectum

Neuroendocrine tumors (NETs) of the distal colon and rectum are also known as hindgut carcinoids based on their common embryologic derivation. Their annual incidence in the United States is rising, primarily as a result of increased incidental detection. Symptoms of rectal NETs include hematochezia, pain, and change in bowel habits. Most rectal NETs are small, submucosal in location, and associated with a very low malignant potential. Tumors larger than 2 cm or those invading the muscularis propria are associated with a significantly higher risk of metastatic spread. Colonic NETs proximal to the rectum are rarer and tend to behave more aggressively. The incidence of rectal NETs in African Americans and Asians is substantially higher than in Caucasians. Colorectal NETs are generally not associated with a hormonal syndrome such as flushing or diarrhea. A multidisciplinary approach is recommended in diagnosing and managing hindgut NETs.

Endoscopic treatment of rectal carcinoid tumors

BACKGROUND

Various methods have been reported for the endoscopic treatment of rectal carcinoid tumors. The present study was designed to identify the optimal treatment strategy for an endoscopic resection.

METHODS

Forty rectal carcinoid tumors of 38 patients were treated endoscopically. The indication criteria, complete resection rate, selection of treatment, local recurrence, distant metastases, and complications were analyzed. All tumors were estimated to measure 1 cm or less in diameter, without muscular invasion, atypical features, and lymph node metastases to the pararectal region.

RESULTS

Complete resection of the lesions was obtained in 75.0% (30/40). The complete resection rates were 20.0% (1/5) by conventional polypectomy, 84.6% (22/26) by a two-channel endoscopic mucosal resection, and 77.8% (7/9) by endoscopic submucosal dissection. The 10 cases that did not show a clear submucosal layer after initial endoscopic treatment received additional endoscopic microwave coagulation therapy. There were no local or distant recurrences in the followed-up periods (median, 6.4 years). No difference was observed in the complete resection rate between two-channel endoscopic mucosal resection and endoscopic submucosal dissection.

CONCLUSIONS

Small carcinoid tumors measuring less than 1 cm in diameter can therefore be managed endoscopically with no recurrence or spread. The selection of endoscopic treatment should be made after taking such factors as cost-effectiveness, expertise, and experience into careful consideration.

Transanal endoscopic microsurgery resection of rectal tumors: outcomes and recommendations

PURPOSE

Transanal endoscopic microsurgery provides a minimally invasive alternative to radical surgery for excision of benign and malignant rectal tumors. The purpose of this study was to review our experience with transanal endoscopic microsurgery to clarify its role in the treatment of different types of rectal pathology.

METHODS

A prospective database documented all patients undergoing transanal endoscopic microsurgery from October 1996 through June 2008. We analyzed patient and operative factors, complications, and tumor recurrence. For recurrence analysis, we excluded patients with fewer than 6 months of follow-up, previous excisions, known metastases at initial presentation, and those who underwent immediate radical resection following transanal endoscopic microsurgery.

RESULTS

Two hundred sixty-nine patients underwent transanal endoscopic microsurgery for benign (n = 158) and malignant (n = 111) tumors. Procedure-related complications (21%) included urinary retention (10.8%), fecal incontinence (4.1%), fever (3.8%), suture line dehiscence (1.5%), and bleeding (1.5%). Local recurrence rates for 121 benign and 83 malignant tumors were 5% for adenomas, 9.8% for T1 adenocarcinoma, 23.5% for T2 adenocarcinoma, 100% for T3 adenocarcinoma, and 0% for carcinoid tumors. All 6 (100%) recurrent adenomas were retreated with endoscopic techniques, and 8 of 17 (47%) recurrent adenocarcinomas underwent salvage procedures with curative intent.

CONCLUSIONS

Transanal endoscopic microsurgery is a safe and effective method for excision of benign and malignant rectal tumors. Transanal endoscopic microsurgery can be offered for (1) curative resection of benign tumors, carcinoid tumors, and select T1 adenocarcinomas, (2) histopathologic staging in indeterminate cases, and (3) palliative resection in patients medically unfit or unwilling to undergo radical resection.

Transanal endoscopic microsurgery for rectal tumors: experience at Korea's National Cancer Center

BACKGROUND

Transanal endoscopic microsurgery (TEM) is a minimally invasive alternative to transanal excision, enabling complete local excision of selected benign or malignant rectal tumors. This study aimed to determine the surgical and oncologic results for rectal tumors excised by TEM.

METHODS

From November 2001 to October 2007, 45 patients underwent TEM for excision of adenoma (13 patients), carcinoid tumor (6 patients), and carcinoma (26 patients). The patients included 27 men and 18 women with a median age of 52 years (range, 22-72 years).

RESULTS

The median tumor distance from the anal verge was 7 cm (range, 3-15 cm), and the median tumor size was 17 mm (range, 2-60 mm). There was no procedure-related morbidity or mortality. However, one patient with rectal carcinoma died of lung cancer during the follow-up period. Of 13 patients with adenomas, 1 patient (7.7%, 1/13) experienced local recurrence 5 months after surgery. No recurrence occurred for six patients with carcinoid tumors. Histologic examination of the carcinomas showed pathologic tumor (pT) stage 0 (ypT0) in 2 patients, pT1 in 17 patients (including ypT1 in 1 patient), pT2 in 6 patients, and pT3 in 1 patient. Immediate salvage surgery was performed for five patients (19%, 5/26). During a median follow-up period of 37 months (range, 5-72 months), one patient (3.8%, 1/26) experienced local recurrence. The overall and disease-free 5-year survival rates for patients with carcinoma were 96.2% and 88.5%, respectively.

CONCLUSIONS

The TEM procedure is a safe and appropriate surgical treatment option for benign rectal tumors. With strict patient selection, it is oncologically safe for early-stage rectal carcinomas.