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

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.

Recurrence after endoscopic resection of small rectal neuroendocrine tumors: a retrospective cohort study

PURPOSE

According to the European Neuroendocrine Tumor Society consensus guidelines, rectal neuroendocrine tumors (NETs) up to 10 mm in size and without poor prognostic factors could be safely removed with endoscopic resection, suggesting omitting surveillance colonoscopy after complete resection. However, the benefit of surveillance colonoscopy is still unknown. In this study, we aimed to report the outcomes after endoscopic resection of small rectal NETs using our surveillance protocol.

METHODS

This retrospective cohort study included patients who underwent endoscopic resection for rectal NETs sized up to 10 mm from January 2013 to December 2019 at our center. We excluded patients without surveillance colonoscopy and those lost to follow-up. We strictly performed surveillance colonoscopy 1 year after endoscopic resection, and every 2 to 3 years thereafter. The primary outcomes were tumor recurrence and occurrence of metachronous tumors during followup.

RESULTS

Of the 54 patients who underwent endoscopic resection for rectal NETs during the study period, 46 were enrolled in this study. The complete resection rates by endoscopic mucosal resection, precutting endoscopic mucosal resection, and endoscopic submucosal dissection were 92.3% (12 of 13), 100% (21 of 21), and 100% (12 of 12), respectively. There was no local or distant recurrence during the median follow-up of 39 months. However, we found that 8.7% (4 of 46) of patients developed metachronous NETs. All metachronous lesions were treated with precutting endoscopic mucosal resection.

CONCLUSION

Surveillance colonoscopy is reasonable after endoscopic resection of small rectal NETs for timely detection and treatment of metachronous lesions. However, larger collaborative studies are needed to influence the guidelines.

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.

Comparison among different techniques for en-bloc resection of rectal lesions: transanal endoscopic surgery vs. endoscopic submucosal dissection vs. full-thickness resection device with Over-The-Scope Clip® System

BACKGROUND

The aim of our retrospective study is to compare the efficacy and indications of transanal endoscopic microsurgery (TEM), endoscopic submucosal dissection (ESD), and endoscopic full-thickness resection device (FTRD) with Over-The-Scope Clip (OTSC®) System for en-bloc resection of rectal lesions.

METHODS

This study collected 76 cases of rectal neoplasms from a single hospital institution. Primary endpoints were complete en-bloc resection, intraprocedural adverse events, R0 en-bloc resection and an early discharge of the patient. Secondary endpoints included procedure-related adverse events.

RESULTS

Mean tumor sizes were statistically significant smaller among patients treated with FTRD rather than TEM and ESD. TEO and FTRD treated patients experienced a higher en-bloc resection rate, with a shorter procedure time and hospital stay. No significant difference concerning the R0 resection was found. TEO and FTRD recorded lower perforation rates as compared to ESD, whereas no difference emerged concerning the bleeding rate and the post-polypectomy syndrome rate.

CONCLUSIONS

Our study showed that each technique has specific features, so that each one offers advantages and disadvantages. Nevertheless, all of them ensure high en-bloc resection rates, whereas no difference exists for R0 resection rate. TEO provides the possibility to remove low rectal large lesions as compared to ESD and FTRD.

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.

Comparison of endoscopic therapies for rectal carcinoid tumors: Endoscopic mucosal resection with circumferential incision versus endoscopic submucosal dissection

BACKGROUND AND OBJECTIVE

Although various endoscopic resection techniques have been established for rectal carcinoid tumors, there remains controversy regarding the best endoscopic treatment modality for these tumors. This study aimed to evaluate and compare the therapeutic efficacy and safety of EMR with circumferential incision (EMR-CI) and endoscopic submucosal dissection (ESD) for endoscopic resection of rectal carcinoid tumors.

METHODS

From March 2012 to June 2016, 66 rectal carcinoid tumors in 66 patients were resected by using EMR-CI (n=30) or ESD (n=36). The rates of both en bloc resection and complete resection, procedure time, procedure-related complications, and local or metastatic recurrence were analyzed retrospectively.

RESULTS

The en bloc resection rate was 96.7% (29/30) and 100% (36/36) for EMR-CI and ESD groups, respectively, and the difference was not statistically significant (P=0.455). The complete resection rate of the ESD group was 97.2% (35/36) and significantly higher than 76.7% (23/30) of the EMR-CI group (P=0.030). The mean procedure time of the ESD group was 20.44±6.64minutes, which was significantly longer than that of the EMR-CI group at 8.47±3.40minutes (P<0.001). The complication rates for ESD and EMR-CI did not differ significantly (0% for EMR-CI vs. 2.8% for ESD, P=1.000). No local or metastatic recurrence was found in either group during the follow-up period.

CONCLUSION

This study suggested that ESD may be a safe, effective, and feasible endoscopic technique for removing rectal carcinoid tumors. ESD showed a similar safety profile and superior efficacy to EMR-CI.

Efficacy and safety of endoscopic submucosal dissection for submucosal tumors of the colon and rectum

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) of colorectal submucosal tumors (SMTs) is becoming increasingly common; however, there have been few large consecutive studies analyzing its therapeutic efficacy and safety. The aim of this study was to evaluate the efficacy, safety, and long-term outcomes of ESD for colorectal SMTs.

METHODS

This retrospective study included 412 consecutive patients with colorectal SMTs who underwent ESD at the Zhongshan Hospital of Fudan University from January 2008 to July 2014. Tumor histopathology, completeness of resection, adverse events, tumor recurrence, and distant metastasis were analyzed.

RESULTS

Complete resection was achieved for 358 lesions (86.9%). Thirteen patients had serious adverse events (3.2%) including bleeding and perforation, and 28 patients (6.8%) had post-ESD electrocoagulation syndrome (PEECS). Because more ESDs for colorectal SMTs were performed by endoscopists, the rate of complete resection increased (78.5% vs 88.5%), and the rate of serious adverse events decreased (9.2% vs 2.0%). SMTs in the colon increased the risk of incomplete resection (19.6% vs 11.3%), serious adverse events (8.7% vs 1.6%), and PEECS (16.3% vs 4.1%). SMTs originating from the muscularis propria and sized ≥20 mm increased the rate of PEECS (22.7% vs 5.9% and 31.3% vs 5.8%, respectively).

CONCLUSION

ESD is effective for resection of colorectal SMTs and rarely causes serious adverse events. Tumor location and the experience of endoscopists influence the complete resection rate and the development of serious adverse events. ESD is feasible for large tumors and tumors in the muscularis propria, but this is associated with relatively high risks of adverse events.

Efficacy of Precut Endoscopic Mucosal Resection for Treatment of Rectal Neuroendocrine Tumors

Background/Aims

Endoscopic resection is the first-line treatment for rectal neuroendocrine tumors (NETs) measuring <1 cm and those between 1 and 2 cm in size. However, conventional endoscopic resection cannot achieve complete resection in all cases. We aimed to analyze clinical outcomes of precut endoscopic mucosal resection (EMR-P) used for the management of rectal NET.

Methods

EMR-P was used to treat rectal NET in 72 patients at a single tertiary center between 2011 and 2015. Both, circumferential precutting and EMR were performed with the same snare device in all patients. Demographics, procedural details, and histopathological features were reviewed for all cases.

Results

Mean size of the tumor measured endoscopically was 6.8±2.8 mm. En bloc and complete resection was achieved in 71 (98.6%) and 67 patients (93.1%), respectively. The mean time required for resection was 9.0±5.6 min. Immediate and delayed bleeding developed in six (8.3%) and 4 patients (5.6%), respectively. Immediate bleeding observed during EMR-P was associated with the risk of delayed bleeding.

Conclusions

Both, the en bloc and complete resection rates of EMR-P in the treatment of rectal NETs using the same snare for precutting and EMR were noted to be high. The procedure was short and safe. EMR-P may be a good treatment choice for the management of rectal NETs.

Evolving role of the endoscopist in management of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NETs) are uncommon gastrointestinal neoplasms but have been increasingly recognized over the past few decades. Luminal NETs originate from the submucosa of the gastrointestinal tract and careful endoscopic exam is a key for accurate diagnosis. Despite their reputation as indolent tumors with a good prognosis, some NETs may have aggressive features with associated poor long-term survival. Management of NETs requires full understanding of tumor size, depth of invasion, local lymphadenopathy status, and location within the gastrointestinal tract. Staging with endoscopic ultrasound or cross-sectional imaging is important for determining whether endoscopic treatment is feasible. In general, small superficial NETs can be managed by endoscopic mucosal resection and endoscopic submucosal dissection (ESD). In contrast, NETs larger than 2 cm are almost universally treated with surgical resection with lymphadenectomy. For those tumors between 11-20 mm in size, careful evaluation can identify which NETs may be managed with endoscopic resection. The increasing adoption of ESD may improve the results of endoscopic resection for luminal NETs. However, enthusiasm for endoscopic resection must be tempered with respect for the more definitive curative results afforded by surgical treatment with more advanced lesions.

Is endoscopic ultrasonography essential for endoscopic resection of small rectal neuroendocrine tumors?

AIM

To evaluate the importance of endoscopic ultrasonography (EUS) for small (≤ 10 mm) rectal neuroendocrine tumor (NET) treatment.

METHODS

Patients in whom rectal NETs were diagnosed by endoscopic resection (ER) at the Pusan National University Yangsan Hospital between 2008 and 2014 were included in this study. A total of 120 small rectal NETs in 118 patients were included in this study. Histologic features and clinical outcomes were analyzed, and the findings of endoscopy, EUS and histology were compared.

RESULTS

The size measured by endoscopy was not significantly different from that measured by EUS and histology (r = 0.914 and r = 0.727 respectively). Accuracy for the depth of invasion was 92.5% with EUS. No patients showed invasion of the muscularis propria or metastasis to the regional lymph nodes. All rectal NETs were classified as grade 1 and demonstrated an L-cell phenotype. Mean follow-up duration was 407.54 ± 374.16 d. No patients had local or distant metastasis during the follow-up periods.

CONCLUSION

EUS is not essential for ER in the patient with small rectal NETs because of the prominent morphology and benign behavior.

Treatment outcomes of endoscopic resection for rectal carcinoid tumors: an analysis of the resectability and long-term results from 46 consecutive cases

AIM

In Japan, most of colorectal carcinoid tumors developed in rectum. The choice of treatment is important because surgical treatment may need to construct artificial anus. Although curative endoscopic resection (ER) is desirable from the point of quality of life, sufficient evidence of endoscopic treatment for rectal carcinoid tumors is not fully obtained.

METHODS

Between April 2001 and August 2013, 46 rectal carcinoid tumors in 46 patients who underwent either with endoscopic mucosal resection with a ligation device (EMR-L) or endoscopic submucosal dissection (ESD) were analyzed retrospectively. The rates of en bloc resection, positive for lateral and/or vertical margin, curative resection, local recurrence, additional treatments, overall and disease-specific survival rate after ER were evaluated during follow-up (median observation period 61.6 months).

RESULTS

Twenty-two lesions were treated by EMR-L and 24 lesions were treated by ESD. Both groups had similar mean tumor size (EMR-L: 6.2 mm, ESD: 6.0 mm). The rate of en bloc resection, negative for both lateral and vertical margins, and curative resection were, respectively, 73%, 63%, and 50% for EMR-L, 100%, 100%, and 83% for ESD. These results suggested that the rate of resectability and curability for ESD was significantly higher than EMR-L (p < 0.05). Complications such as perforation and bleeding did not occur in both groups. Fifteen patients were judged as non-curative and 3 patients underwent additional surgery and lymph node metastasis was evident in 1 patient. Remained 11 patients were carefully followed-up, and so far no obvious recurrence was found. Thirty-two patients (84%) were eligible for long-term follow-up and 5-year overall and disease-specific survival rates were 100% and 100%, respectively.

CONCLUSION

The long-term outcomes of ER for rectal carcinoid tumors were excellent. ESD has advantage for resectability and curability compared with EMR-L; therefore, ESD is more favorable procedure as treatment for rectal carcinoid tumors.

Efficacy and Safety of Endoscopic Submucosal Dissection for Colorectal Carcinoids

BACKGROUND & AIMS

Although endoscopic submucosal dissection (ESD) of colorectal carcinoids is increasing, little is known about long-term outcomes of patients. We investigated the efficacy and safety of ESD of colorectal carcinoids and evaluated long-term outcomes, including local recurrence and metastasis.

METHODS

We performed a retrospective analysis of data collected from 239 consecutive patients with colorectal carcinoids <20 mm who underwent endoscopic ultrasonography (to evaluate the size of tumor and the depth of invasion), followed by ESD from January 2007 through October 2012 at the Zhongshan Hospital of Fudan University. Histology and patient data were collected during a median follow-up period of 52 months (range, 25-94 months) to determine tumor stage and type, completeness of resection, complications, tumor recurrence, and distant metastasis.

RESULTS

En bloc resection was achieved for all of the 239 treated lesions; tumor tissues were completely resected for 216 of the lesions (90.38%). Eight patients had ESD-related complications (3.35%). As more ESDs were performed by endoscopists, the rate of complete tumor resection increased, and the rate of complications decreased. ESD of carcinoids in colon increased the risk of non-R0 resection and the rate of complications. During the follow-up period, all patients remained free from local recurrence. However, distant metastases were detected in 6 patients (2.51%); lymphovascular invasion was a risk factor for metastasis.

CONCLUSIONS

ESD is effective for the resection of rectal carcinoids <20 mm and causes complications in less than 4% of patients. ESD for colonic carcinoids is feasible but associated with a higher non-R0 resection rate and a trend toward higher complications risk. Tumor features and stage determine risk for distant metastasis, so long-term follow-up is essential.

[Rectal neuroendocrine tumors: surgical therapy]

The incidence of rectal neuroendocrine tumors (NET) has increased in recent years. Most of these neoplasms are asymptomatic and are diagnosed by colonoscopy screening, which could be one of the reasons for the increasing occurrence. As less than 1 % of rectal NET produce serotonin they are practically never discovered due to a carcinoid syndrome. The current guidelines of the European (ENETS) and North American (NANETS) Neuroendocrine Tumor Societies support clinicians with useful diagnostic and treatment algorithms. The most important criteria for therapy are tumor size and histopathological risk factors for metastases. For well-differentiated rectal neuroendocrine neoplasms < 1 cm, local endoscopic or surgical excision is recommended. Due to the lack of evidence tumors sized 1-2 cm represent a grey area for prognosis and treatment. All NET > 1.5 cm must be excised by radical surgery as low anterior rectal resection or abdominoperineal extirpation with total mesorectal excision (TME). Resectable liver and lung metastases of well-differentiated NETs should be surgically treated with curative intent.

A comparison of endoscopic treatments in rectal carcinoid tumors

BACKGROUND

Various endoscopic techniques for rectal carcinoid tumors have been developed recently. In this study, we compared the outcomes of conventional endoscopic mucosal resection (EMR), strip biopsy, and EMR after circumferential precutting (EMR-P).

METHODS

From March 2004 to July 2014, the medical records of 188 patients (190 rectal carcinoid tumors) who were treated with an endoscopic procedure for rectal carcinoid tumors were investigated retrospectively. The characteristics of the patients and tumors, the selection of the treatment method, the rate of complete resection, and the rate of complications were analyzed retrospectively.

RESULTS

Forty-seven, 75 and 68 cases of EMR, strip biopsy and EMR-P were performed, respectively. The mean procedure time was not significantly different between the EMR, strip biopsy and EMR-P cases (5.6, 6.5 and 7.4 min, respectively, P = 0.119). En bloc resection was achieved in most of the cases (97.8, 98.7 and 95.5 % in the EMR, strip biopsy and EMR-P cases, respectively). However, histologic examination showed positive lateral or deep resection margins in 57 out of 190 cases (30.0 %). Multivariate analysis showed that the strip biopsy and EMR-P methods were independent factors for pathologic complete resection (negative in both lateral and deep resection margins), with odds ratios for margin involvement of 0.20 and 0.43 with 95 % confidence intervals from 0.08 to 0.47 and 0.19 to 0.96, respectively. In all the follow-up cases (81 of 190, 42.6 %), no local recurrence or distal metastasis was found.

CONCLUSIONS

Compared to conventional EMR, strip biopsy and EMR-P had a lower risk of incomplete resection. The procedure time and complication rate did not differ between the three groups, and no recurrence was detected during the follow-up period. Strip biopsy and EMR-P are safe and effective methods for the treatment of rectal carcinoid tumors.

Neuroendocrine tumors of the luminal gastrointestinal tract

CONTEXT

Neuroendocrine tumors (NETs) of the gastrointestinal tract have been recognized for more than a century. Despite histologic similarities between different sites in the tract, behavior varies between areas. All of these tumors have malignant potential, but determination of exact risk is difficult.

OBJECTIVES

To review the diagnosis of luminal gastrointestinal NETs, including a discussion of grading. Grading by mitotic index/activity, in conjunction with tumor size/stage, has been found to be the strongest predictor of behavior.

DATA SOURCES

Literature review of luminal gastrointestinal NETs was performed and the results summarized.

CONCLUSIONS

Our understanding of these lesions is incomplete and continues to evolve.

Advantage of endoscopic mucosal resection with a cap for rectal neuroendocrine tumors

AIM: To compare the outcomes of endoscopic mucosal resection with a cap (EMR-C) with those of endoscopic submucosal dissection (ESD) for the resection of rectal neuroendocrine tumors.

METHODS: One hundred and sixteen lesions in 114 patients with rectal neuroendocrine tumor (NET) resected with EMR-C or ESD were included in the study. This study was performed at Pusan National University Yangsan Hospital between July 2009 and August 2014. We analyzed endoscopic complete resection rate, pathologic complete resection rate, procedure time, and adverse events in the EMR-C (n = 65) and ESD (n = 51) groups. We also performed a subgroup analysis by tumor size.

RESULTS: Mean tumor size was 4.62 ± 1.66 mm in the EMR-C group and 7.73 ± 3.14 mm in the ESD group (P < 0.001). Endoscopic complete resection rate was 100% in both groups. Histologic complete resection rate was significantly greater in the EMR-C group (92.3%) than in the ESD group (78.4%) (P = 0.042). Mean procedure time was significantly longer in the ESD group (14.43 ± 7.26 min) than in the EMR-C group (3.83 ± 1.17 min) (P < 0.001). Rates of histologic complete resection without complication were similar for tumor diameter ≤ 5 mm (EMR-C, 96%; ESD, 100%, P = 0.472) as well as in cases of 5 mm < tumor diameter ≤ 10 mm (EMR-C, 80%; ESD, 71.0%, P = 0.524).

CONCLUSION: EMR-C may be simple, faster, and more effective than ESD in removing rectal NETs and may be preferable for resection of small rectal NETs.

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.

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.

Efficacy and safety of endoscopic resection therapies for rectal carcinoid tumors: a meta-analysis

PURPOSE

Several endoscopic resection therapies have been applied for the treatment of rectal carcinoid tumors. However, there is currently no consensus regarding the optimal strategy. We performed a meta-analysis to compare the efficacy and safety of endoscopic mucosal resection (EMR) or modified EMR (m-EMR) versus endoscopic submucosal dissection (ESD) for the treatment of rectal carcinoid tumors.

MATERIALS AND METHODS

PubMed, Web of Science, Medline, Embase and CNKI were searched up to the end of January 2014 in order to identify all studies on the effects of EMR (or m-EMR) and ESD on rectal carcinoid tumors.

RESULTS

A total of fourteen studies involving 782 patients were included. The pooled data suggested a significantly higher rate of pathological complete resection among patients treated with ESD or m-EMR than those treated with EMR [odds ratio (OR)=0.42, 95% confidence interval (CI): 0.25-0.71; OR=0.10, 95% CI: 0.03-0.33, respectively], while there was no significant difference between the m-EMR group and ESD group (OR=1.19, 95% CI: 0.49-2.86); The procedure time of ESD was longer than EMR or m-EMR groups [mean differences (MD)=-11.29, 95% CI: -14.19 - -8.38, MD= -10.90, 95% CI: -18.69 - -3.11, respectively], but it was insignificance between the EMR and m-EMR groups. No significant differences were detected among the treatment groups with regard to complications or recurrence.

CONCLUSION

The results of this meta-analysis suggest that treatment of rectal carcinoid tumors with ESD or m-EMR is superior to EMR, and the efficacy of m-EMR is equivalence to ESD treatment. However, more well-designed studies are needed to confirm these findings.

Diagnostic accuracy of endoscopic ultrasonography for rectal neuroendocrine neoplasms

AIM: To investigate the diagnostic accuracy of endoscopic ultrasonography (EUS) for rectal neuroendocrine neoplasms (NENs) and the differential diagnosis of rectal NENs from other subepithelial lesions (SELs).

METHODS: The study group consisted of 36 consecutive patients with rectal NENs histopathologically diagnosed using biopsy and/or resected specimens. The control group consisted of 31 patients with homochronous rectal non-NEN SELs confirmed by pathology. Epithelial lesions such as cancer and adenoma were excluded from this study. One EUS expert blinded to the histological results reviewed the ultrasonic images. The size, original layer, echoic intensity and homogeneity of the lesions and the perifocal structures were investigated. The single EUS diagnosis recorded by the EUS expert was compared with the histological results.

RESULTS: All NENs were located at the rectum 2-10 cm from the anus and appeared as nodular (n = 12), round (n = 19) or egg-shaped (n = 5) lesions with a hypoechoic (n = 7) or intermediate (n = 29) echo pattern and a distinct border. Tumors ranged in size from 2.3 to 13.7 mm, with an average size of 6.8 mm. Homogeneous echogenicity was seen in all tumors except three. Apart from three patients (stage T2 in two and stage T3 in one), the tumors were located in the second and/or third wall layer without involvement of the fourth and fifth layers. In the patients with stage T1 disease, the tumors were located in the second wall layer only in seven cases, the third wall layer only in two cases, and both the second and third wall layers in 27 cases. Approximately 94.4% (34/36) of rectal NENs were diagnosed correctly by EUS, and 74.2% (23/31) of other rectal SELs were classified correctly as non-NENs. Eight cases of other SELs were misdiagnosed as NENs, including two cases of inflammatory lesions and one case each of gastrointestinal tumor, endometriosis, metastatic tumor, lymphoma, neurilemmoma, and hemangioma. The positive predictive value of EUS for rectal NENs was 80.9% (34/42), the negative predictive value was 92.0% (23/25), and the diagnostic accuracy was 85.1%.

CONCLUSION: EUS has satisfactory diagnostic accuracy for rectal NENs with good sensitivity, but unfavorable specificity, making the differential diagnosis of NENs from other SELs challenging.