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

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.

Difficulty of predicting lymph node metastasis on CT in patients with rectal neuroendocrine tumors

Background

Surgical indications for rectal neuroendocrine tumors with potential lymph node metastasis remain controversial. Although accurate preoperative diagnosis of nodal status may be helpful for treatment strategy, scant data about clinical values of lymph node size have been reported. The aim of this retrospective study was to investigate the relationship between lymph node size and lymph node metastasis.

Methods

Participants comprised 102 patients who underwent rectal resection with total mesenteric excision or tumor-specific mesenteric excision and in some cases additional lateral pelvic lymph node dissection for rectal neuroendocrine tumor between June 2005 and September 2016. All lymph nodes from specimens were checked and measured.

Results

Pathological lymph node metastasis was confirmed in 37 patients (36%), including 6 patients (5.8%) with lateral pelvic lymph node metastasis. A total of 1169 lymph nodes in the mesorectum were retrieved from all specimens, with 78 lymph nodes (6.7%) showing metastasis. Mean length (long-axis diameter) of metastatic lymph nodes in the mesorectum was 4.31 mm, significantly larger than that of non-metastatic lymph nodes (2.39 mm, P<0.01). The optimal cut-off of major axis length for predicting mesorectal lymph node metastasis was 3 mm. We could predict lymph node metastasis in only 7 patients (21%) from preoperative multidetector-row computed tomography.

Conclusions

Metastatic lymph nodes were small, so predicting lymph node metastasis from preoperative computed tomography is difficult. Alternative modalities with a scan width less than 3 mm may be needed to predict lymph node metastasis of rectal NET with low cost and labour requirements.

Predictors of Metastases in Rectal Neuroendocrine Tumors: Results of a National Cohort Study

BACKGROUND

Rectal neuroendocrine tumors are often found incidentally. Local excision alone has been advocated for lesions ≤2 cm; however, the evidence base for this approach is limited.

OBJECTIVE

Associations among tumor size, degree of differentiation, and presence of distant metastatic disease were examined.

DESIGN

This was a retrospective cohort study.

SETTINGS

This study was conducted using a nationwide cohort.

PATIENTS

A total of 4893 patients with rectal neuroendocrine tumors were identified in the National Cancer Database (2006-2015).

MAIN OUTCOME MEASURES

Logistic regression analyses were used to evaluate associations among tumor size, degree of differentiation, and presence of regional and distant metastatic disease. Cut point analysis was performed to identify an optimal size threshold predictive of distant metastatic disease.

RESULTS

Of patients included for analysis, 3880 (79.3%) had well-differentiated tumors, 540 (11.0%) had moderately differentiated tumors, and 473 (9.7%) had poorly differentiated tumors. On logistic regression, increasing size was associated with a higher likelihood of pathologically confirmed lymph node involvement (among patients undergoing proctectomy), and both size and degree of differentiation were independently associated with a higher likelihood of distant metastatic disease. The association between tumor size and distant metastatic disease was stronger for well-differentiated and moderately differentiated tumors (OR = 1.4; p < 0.001 for both) than for poorly differentiated tumors (OR = 1.1; p = 0.010). For well-differentiated tumors, the optimal cut point for the presence of distant metastatic disease was 1.15 cm (area under the curve = 0.88; 88% sensitive and 88% specific). Tumors ≥1.15 cm in diameter were associated with a substantially increased incidence of distant metastatic disease (72/449 (13.8%)). For moderately differentiated tumors, the optimal cut point was also 1.15 cm (area under the curve = 0.87, 100% sensitive and 75% specific).

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSIONS

Tumor size and degree of differentiation are predictive of regional and distant metastatic disease in rectal neuroendocrine tumors. Patients with tumors >1.15 cm are at substantial risk of distant metastasis and should be staged and managed accordingly. See Video Abstract at http://links.lww.com/DCR/A778.

Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from the diffuse neuroendocrine system. They frequently originate in the gastroenteropancreatic (GEP) tract and the bronchopulmonary tree, and their incidence has steadily increased in the last 3 decades. Fundamental biologic and genomic differences underlie the clinical heterogeneity of NETs, and distinct molecular features characterize NETs of different grades and different primary sites. Although surgery remains the cornerstone of treatment for localized tumors, systemic treatment options for patients with metastatic NETs have expanded considerably. Somatostatin analogs have demonstrated both antisecretory and antitumor efficacy. Peptide receptor radionuclide therapy with lutetium-177 dotatate (¹⁷⁷ Lu-DOTATATE) has been approved for advanced GEP-NETs. The antitumor activity of everolimus has been demonstrated across a wide spectrum of NETs, and the antiangiogenic agent sunitinib has been approved for pancreatic NETs (pNETs). Chemotherapy with temozolomide and capecitabine has recently demonstrated an unprecedented prolongation of progression-free survival in a randomized trial of pNETs. Multiple retrospective series have reported the efficacy of liver-directed therapies both for palliating symptoms of hormone excess and for controlling tumor growth. Telotristat, an oral inhibitor of tryptophan hydroxylase, has been shown to reduce diarrhea in patients with carcinoid syndrome. Defining the therapeutic algorithm and identifying biomarkers predictive of response to treatments are among the main priorities for the next decade of research in the NET field.

Intestinal occlusion by stenotic neuroendocrine tumours of left colon and concomitant association with small bowel gastrointestinal stromal tumours: A case report

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Gastrointestinal stromal tumours (GIST) and Neuroendocrine tumours (NET) of the gastroenteropancreatic tract are rare neoplasms.

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Treatment for colonic NETs was similar to colonic adenocarcinoma, with segmental resection and lymphadenectomy.

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The associationof GIST and NET is difficult to suspect Serum CgA remains the most important biochemical marker in the diagnostics, monitoring, and establishing the prognosis in colorectal NETs.

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Early diagnosis of concomitant tumors such as GIST and NET will guarantee a better outcome of patients.

Introduction

The association between Gastrointestinal Stromal Tumours (GIST) and Neuroendocrine Tumours (NET) is very rare. These tumours have various clinical expressions and sometimes are asymptomatic. Synchronous NETs and GISTs have been already described in literature in few case reports. On the other hand, there is no mention of concomitant presence of discending colon NEC-G3 and small intestinal GIST.

Presentation of case: we presented a case of a patient with clinical evidence of intestinal occlusion and radiological and intraoperative aspects of an adenocarcinoma of the left colon with a single metastasis on small bowel. The pathology analysis of the tumour showed a stenotic left colon NEC-G3 and a small bowel GIST.

Discussion

In this case report GIST was surgically treated as a small bowel ripetitive lesion and NET as a left colon adenocarcinoma. These tumours may have a similar presentation in terms of symptoms, endoscopic findings and imaging results.

Conclusion

Concomitant NEC and GIST is rare but it is important to investigate patients before surgery in order to distinguish these from other tumours because of the different prognosis.

Small Bowel and Colorectal Carcinoids

Neuroendocrine tumors, or carcinoid tumors, of both the midgut and hindgut are quite rare, but their incidence is increasing. Surgery is the treatment of choice in patients who can tolerate an operation and have operable disease. Options for the treatment of metastatic disease include cytoreductive surgery, somatostatin analogues, interferon α, local liver therapies (hepatic arterial embolization, ablation), chemotherapy, Peptide-Receptor Radionucleotide Radiotherapy, angiogenesis inhibitors, and mammalian target of rapamycin inhibitors.

Endoscopic mucosal resection with suction vs. endoscopic submucosal dissection for small rectal neuroendocrine tumors: a meta-analysis

OBJECTIVE

There are no guidelines or consensus on the optimal treatment measures for small rectal neuroendocrine tumors (NETs) at present. This meta-analysis was conducted to compare the efficacy and safety of endoscopic mucosal resection (EMR) with suction and endoscopic submucosal dissection (ESD) for the small rectal NETs.

METHODS

The literature searches were conducted using Pubmed and Embase databases, and then a meta-analysis was performed. The primary outcome was complete resection rate, and the secondary outcomes were complication rate, procedure time, and recurrence rate.

RESULTS

Fourteen studies with 823 patients were included in our meta-analysis. The overall complete resection rates in EMR with suction and ESD procedure were 93.65% (472/504) and 84.08% (243/289), respectively. The pooled analysis showed that EMR with suction could achieve a higher complete resection rate than ESD with significance (OR: 4.08, 95% CI: 2.42-6.88, p < .00001) when the outlier study was excluded, and procedure time was significantly shorter in the EMR with suction group than in the ESD group (SMD: -1.59, 95% CI: -2.27 to -0.90, p < .00001). Moreover, there was no significant difference in overall complication rate (OR: 0.56, 95% CI: 0.28-1.14, p = .11) and overall recurrence rate (OR: 0.76, 95% CI: 0.11-5.07, I²=48%) between EMR with suction and ESD group.

CONCLUSIONS

The present meta-analysis mostly based on retrospective studies show that EMR with suction is superior to ESD for small rectal NETs (≤10 mm) with higher complete resection rate, shorter procedure time, and similar overall complication rate and recurrence.

Robotic transanal microsurgery for high early rectal neoplasia (T0-T1, N0 lesions), case series of 10 patients

PURPOSE/BACKGROUND

In 2017, an estimated 39 910 people will receive a new diagnosis of rectal cancer. Current surgical guidelines limit transanal excision of early rectal neoplasia to 8 cm from the anal verge. We report that R0 resection of higher rectal cancers is possible using transanal robotic microsurgery.

METHODS/INTERVENTIONS

Ten cases of robotic assisted transanal surgery for early stage disease (T0-T1, N0) between 2013 and 2016 were reviewed.

RESULTS/OUTCOMES

All cases were diagnosed preoperatively with colonoscopy, and the average distance from the anal verge was 11.1 cm. The average operative time was 167 minutes, and the average blood loss was 37.5 cc. Four cases required intraoperative conversion; one conversion required robotic abdominal access to repair a proctotomy. All margins were histologically negative, and 6-month follow-up showed no recurrences.

CONCLUSION/DISCUSSION

Transanal robotic surgery may provide the colorectal surgeon a method to address rectal lesions farther from the anal verge.

Histomorphometric evaluation of the Ki-67 proliferation rate and CD34 microvascular and D2-40 lymphovascular densities drives the pulmonary typical carcinoid outcome

Ki-67 has shown promise as a prognostic factor in pulmonary carcinoids. In this study, we sought to validate the importance of Ki-67 and study the relationships between Ki-67 and other stromal biomarkers of vascular density. We examined Ki-67, CD34, and D2-40 in tumor tissues from 128 patients with surgically excised typical carcinoid of the lung. We used immunohistochemistry and morphometry to evaluate the amount of tumor staining for cellular proliferation (Ki-67), microvascular density (CD34-MVD), and D2-40 lymphovascular density. The main outcome was overall survival, considered as life expectancy until death from metastasis. Specimens from patients with central tumors showed high CD34-MVD (P = .01), which was also significantly associated with a compromised surgical margin, lymph node metastasis, and clinical stage Ib. Equally significant was high D2-40 lymphovascular density in central specimens with a compromised surgical margin and lymph node metastasis. A high Ki-67 proliferation rate was significantly associated with tumors from patients with clinical stage IIb, IIIa, and IV disease. Multivariate Cox model analysis demonstrated that tumor location and stage, surgical margin, tumor size, and N stage were significantly related to survival time (P < .05). Quantitative staining of the tumor for Ki-67 and CD34-MVD served as prognostic factors (P < .05), which were more relevant than the surgical and pathological stage. Ki-67 greater than 5% and CD34-MVD greater than 7% staining comprise a subset of patients with higher death hazard; this outcome may harbor evidence for further prospective studies of target therapy after surgical resection.

How should incidental NEN of the pancreas and gastrointestinal tract be followed?

Neuroendocrine gastro-entero-pancreatic neoplasms (GEP-NENs) constitute a heterogeneous group of tumors, whose incidence has increased over the years. The most frequent site for primary disease is the stomach followed by small and large intestine, and pancreas. In the last decade, a dramatic growing in the incidence of small, incidental GEP-NENs has been recorded. In parallel, an increasing attitude toward more conservative approaches instead of surgical management has being widely spreading. This is particularly true for small, asymptomatic, pancreatic NEN as for these tumor forms an active surveillance has proven to be safe and feasible. Primary site and biological features of the neoplasms lead to different strategies and indications for surveillance and follow-up. This review focuses on the current evidence on modality and timing of surveillance and conservative treatment of incidentally discovered lesions.

Flushing Disorders Associated with Gastrointestinal Symptoms: Part 1, Neuroendocrine Tumors, Mast Cell Disorders and Hyperbasophila

Flushing is the subjective sensation of warmth accompanied by visible cutaneous erythema occurring throughout the body with a predilection for the face, neck, pinnae, and upper trunk where the skin is thinnest and cutaneous vessels are superficially located and in greatest numbers. Flushing can be present in either a wet or dry form depending upon whether neural-mediated mechanisms are involved. Activation of the sympathetic nervous system results in wet flushing, accompanied by diaphoresis, due to concomitant stimulation of eccrine sweat glands. Wet flushing is caused by certain medications, panic disorder and paroxysmal extreme pain disorder (PEPD). Vasodilator mediated flushing due to the formation and release of a variety of biogenic amines, neuropeptides and phospholipid mediators such as histamine, serotonin and prostaglandins, respectively, typically presents as dry flushing where sweating is characteristically absent. Flushing occurring with neuroendocrine tumors accompanied by gastrointestinal symptoms is generally of the dry flushing variant, which may be an important clinical clue to the differential diagnosis. A number of primary diseases of the gastrointestinal tract cause flushing, and conversely extra-intestinal conditions are associated with flushing and gastrointestinal symptoms. Gastrointestinal findings vary and include one or more of the following non-specific symptoms such as abdominal pain, nausea, vomiting, diarrhea or constipation. The purpose of this review is to provide a focused comprehensive discussion on the presentation, pathophysiology, diagnostic evaluation and management of those diseases that arise from the gastrointestinal tract or other site that may cause gastrointestinal symptoms secondarily accompanied by flushing. This review is divided into two parts given the scope of conditions that cause flushing and affect the gastrointestinal tract: Part 1 covers neuroendocrine tumors (carcinoid, pheochromocytomas, vasoactive intestinal polypeptide, medullary carcinoma of the thyroid), polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS), and conditions involving mast cells and basophils; while Part 2 covers dumping syndrome, mesenteric traction syndrome, rosacea, hyperthyroidism and thyroid storm, anaphylaxis, panic disorders, paroxysmal extreme pain disorder, and food, alcohol and medications.

A small, well-differentiated rectal neuroendocrine tumor with multiple lymph node metastases: A case report

The incidence of rectal neuroendocrine tumor (NET), which is often diagnosed during routine surveillance endoscopy, is increasing. The majority of these tumors are small and asymptomatic, possessing benign features with favorable prognoses. At present, small rectal NETs without high-risk factors are typically treated by local resection, including endoscopic mucosal resection, endoscopic submucosal dissection, or transanal endoscopic microsurgery, with or without additional imaging follow-up by abdominal computed tomography or magnetic resonance imaging. The present study, however, describes a case of a small rectal NET without any known risk factors, which was accompanied by substantial locoregional lymph node metastasis, underscoring the importance of imaging studies for rectal NETs.

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.

Entering the third decade of experience with octreotide LAR in neuroendocrine tumors: A review of current knowledge

Gastroenteropancreatic neuroendocrine tumors (NETs) are a relatively rare group of heterogeneous neoplasms. The most significant advance in therapy of NETs has been the advent of the somatostatin analog octreotide, which represents a cornerstone in their management and dramatically changed the therapeutic landscape. Octreotide long-acting release (LAR) was developed to overcome some of the limitations of octreotide. Several clinical studies, including PROMID and RADIANT-2, have validated the clinical benefits of octreotide LAR in NETs, with tumor shrinkage in about 10% of patients and tumor stabilization in roughly half of cases. While the use of octreotide LAR is well-consolidated in NETs, some open questions remain. These include the use of high-dose octreotide LAR, as there is evidence that higher dose may provide longer disease control, and nonstandard treatment schedules, with administration every 21 days instead of 28 days, as well as their use in combination with targeted agents or peptide receptor radiotherapy in clinical practice. After 3 decades of clinical experience with octreotide LAR, the drug has a well-established safety profile. It is well-tolerated and treatment discontinuations due to adverse events are uncommon. One exception is cholelithiasis, which may increase with longer duration of treatment. According to the literature data, octreotide LAR is currently recommended in both functioning and nonfunctioning advanced NETs. This review summarizes the available clinical data with octreotide LAR and also provides future perspectives on its possible uses in patients with NETs.

Long-term Outcome of Small, Incidentally Detected Rectal Neuroendocrine Tumors Removed by Simple Excisional Biopsy Compared With the Advanced Endoscopic Resection During Screening Colonoscopy

BACKGROUND

Incidental, small rectal neuroendocrine tumors during colonoscopy screening are sometimes removed using biopsy forceps. Few studies have examined the clinical course of rectal neuroendocrine tumors removed by simple excisional biopsy.

OBJECTIVE

We investigated the long-term outcome of rectal neuroendocrine tumors removed by simple excisional biopsy compared with standard endoscopic resection.

DESIGN

This was a cohort study.

SETTINGS

This study was performed at a healthcare center in Korea.

PATIENTS

We enrolled patients with rectal neuroendocrine tumors detected during a screening colonoscopy between 2003 and 2015.

MAIN OUTCOME MEASURES

The clinical characteristics and long-term outcomes (overall survival and disease-free survival) of small neuroendocrine tumors <10 mm were compared between the simple excisional biopsy group and advanced endoscopic resection group.

RESULTS

In total, 166 patients were diagnosed with rectal neuroendocrine tumors (≤5 mm, n = 100; 6-9 mm, n = 50; 10-19 mm, n = 15; ≥20 mm, n = 1). Among the 150 patients with neuroendocrine tumors <10 mm, follow-up endoscopy was performed on 99 (59.6%). All of the tumors were confined to the mucosa or submucosa. Thirty-one and 68 patients were included in the simple excisional biopsy and advanced endoscopic resection groups. The overall follow-up duration was 6.5 years (range, 1.0-12.8 y). Neither overall nor disease-related death occurred. Two patients exhibited local recurrence (6.5%, at 8 and 11 y) in the simple excisional biopsy group and 1 patient (1.5%, at 7 y) in the advanced endoscopic resection group, resulting in no significant difference (p = 0.37). All of the recurrences were diagnosed >5 years from initial diagnosis and successfully treated endoscopically.

LIMITATIONS

More long-term data should be warranted.

CONCLUSIONS

The long-term outcome of small rectal neuroendocrine tumors <10 mm removed by simple excisional biopsy was excellent. Neither overall survival nor disease-free survival significantly differed between the simple excisional biopsy group and the advanced endoscopic resection group. Thus, simple excisional biopsy and long-term follow-up can be cautiously applied for small rectal neuroendocrine tumors in clinical practice. See Video Abstract at http://links.lww.com/DCR/A406.

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.

Clinical impact of endoscopic ultrasonography on the management of neuroendocrine tumors: lights and shadows

The incidence of gastroenteropancreatic neuroendocrine neoplasms has increased in the recent decades. An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published mostly between year 1997 and June 2017, using both medical subject heading (MeSH) terms and free-language keywords about the accuracy and diagnostic and therapeutic role of endoscopic ultrasound in the context of gastro-entero-pancreatic neuroendocrine neoplasms. Endoscopic ultrasound is the modality of choice for diagnosing pancreatic neuroendocrine neoplasms and for the locoregional staging of gastric, duodenal, pancreatic and rectal neuroendocrine neoplasms; in particular, in the setting of pancreatic neuroendocrine neoplasms it has demonstrated higher accuracy in tumor detection than other imaging modalities. Furthermore, the possibility of tattooing pancreatic lesions by endoscopic ultrasound fine needle aspiration may help surgeons to locate the tumor and avoid any demolition surgery. Finally, endoscopic ultrasound-guided therapies have been proposed and used in several studies for patients unsuitable for surgery, with good results on the control of symptoms and the reduction of tumor burden.

Nomogram based on tumor-associated neutrophil-to-lymphocyte ratio to predict survival of patients with gastric neuroendocrine neoplasms

AIM

To assess the predictive value of the tumor-associated neutrophil-to-lymphocyte ratio in terms of the clinical outcomes of patients with gastric neuroendocrine neoplasms after radical surgery.

METHODS

Data were retrospectively collected from 142 patients who were diagnosed with gastric neuroendocrine neoplasms and who underwent radical gastrectomy at our department from March 2006 to March 2015. These data were retrospectively analyzed, and a receiver operating characteristic curve analysis was used to identify the optimal value of the tumor-associated neutrophil-to-lymphocyte ratio. Univariate and multivariate survival analyses were used to identify prognostic factors. A nomogram was then applied to predict clinical outcomes after surgery.

RESULTS

The tumor-associated neutrophil-to-lymphocyte ratio was significantly associated with tumor recurrence, especially with liver metastasis and lymph node metastasis (P < 0.05 for both), but not with clinical characteristics (P > 0.05 for all). A multivariate Cox regression analysis identified the tumor-associated neutrophil-to-lymphocyte ratio as an independent prognostic factor for recurrence-free survival and overall survival (P < 0.05 for both). The concordance index of the nomograms, which included the tumor-associated neutrophil-to-lymphocyte ratio, Ki-67 index, and lymph node ratio, was 0.788 (0.759) for recurrence-free survival (overall survival) and was higher than the concordance index of the traditional TNM staging system [0.672 (0.663)].

CONCLUSION

The tumor-associated neutrophil-to-lymphocyte ratio is an independent prognostic factor in patients with gastric neuroendocrine neoplasms. Nomograms that include the tumor-associated neutrophil-to-lymphocyte ratio, Ki-67 index, and lymph node ratio have a superior ability to predict clinical outcomes of postoperative patients.

Chemotherapy in NETs: When and how

The majority of neuroendocrine tumours (NETs) are well-differentiated tumours that follow an indolent course, in contrast to a minority of poorly differentiated neuroendocrine carcinomas (NECs) which exhibit an aggressive course and assocaited with an overall short survival. Although surgery is the only curative treatment for NETs it is not always feasible,necessitating the application of other therapies including chemotherapy. Streptozotocin (STZ)-based regimens have long been used for advanced or metastatic well-to-moderately differentiated (G1-G2) NETs, especially those originating from the pancreas (pNETs). In poorly differentiated grade 3 (G3) tumours, platinum-based chemotherapy is recommended as first-line therapy, albeit without durable responses. Although data for temozolomide (TMZ)-based chemotherapy are still evolving, this treatment may replace STZ-based regimens in pNETs due to its better tolerability and side effect profile. In addition, there is evidence that TMZ could also be used in the subgroup of well-differentiated G3 NETs. There is less clear-cut evidence of a benefit for chemotherapy in intestinal NETs, but still evolving data suggest that TMZ may be efficacious in particular patients. In lung and thymic carcinoids, chemotherapy is reserved for patients with progressive metastatic disease in whom other treatment options are unavailable. Overall, chemotherapy is indicated in patients who have progressed on first-line treatment with somatostatin analogues, have extensive tumour load or exhibit rapid growth following a period of follow-up, and/or have a high proliferative rate; it may occasionally can be used in a neo-adjuvant setting. Prospective randomised studies are awaited to substantiate the role of chemotherapy in the therapeutic algorithm of NETs along with other evolving treatments.

Predictive Factors for Lymph Node Metastasis and Prognostic Factors for Survival in Rectal Neuroendocrine Tumors

INTRODUCTION

Neuroendocrine tumors have malignant potential, and lymph node metastasis can occur. This study aimed to identify predictive factors of lymph node metastasis and prognostic factors for survival in rectal neuroendocrine tumors.

METHODS

Sixty-four patients underwent endoscopic or surgical treatment for rectal NET. The data on these patients were collected in our database prospectively and reviewed retrospectively.

RESULTS

Transanal excision was performed in 28 (43.8%) patients, endoscopic mucosal resection or submucosal dissection was performed in 15 (23.4%) patients, and radical resection was performed in 21 (31.8%) patients. Lymph node and distant metastasis was present in 16 (25.0%) and fir (7.8%) patients. The significant risk factors for lymph node metastasis identified in the multivariable analyses were tumor size (≥ 2 cm, p = 0.003) and tumor grade (G2, p < 0.001; G3, p = 0.008). In patients with a tumor smaller than 2 cm, the risk factors for lymph node metastasis included the tumor grade, mitosis count, and Ki-67 index. The median follow-up period was 30.0 months, and recurrence developed in four (6.8%) patients. The significant prognostic factors for survival included tumor size, T stage, lymph node metastasis, and tumor grade.

CONCLUSION

Tumor grade combined with tumor size is an important predictive factor for lymph node metastasis and could serve as a prognostic factor for survival outcomes.

Local resection of rectal neuroendocrine tumor with first clinical manifestation of giant liver metastasis by transanal endoscopic microsurgery: A case report

RATIONALE

Rectal neuroendocrine tumor (NET) is a relatively rare tumor. Well-differentiated NETs (G1 and G2) rarely display distant metastasis at initial diagnosis. Currently, treatment for the primary lesions of rectal NETs with liver metastasis remains controversial. The liver metastasis was resected in local hospital. Transanal endoscopic microsurgery (TEM) has emerged as an effective minimally invasive surgery for local resection of lower rectal lesions. Herein, we reported the initial application of TEM to remove the rectal primary lesion in patients with low rectal NETs (G2) with giant liver metastases.

PATIENT CONCERNS

The patient, a 45-year-old woman, was primarily diagnosed with hepatocellular carcinoma and underwent curative resection of a giant liver lesion in a local hospital. Nevertheless, the postoperative pathologic examination revealed that the lesion was an NET (G2). The colonoscopy then showed a nodule 1.4 cm in diameter, 4 cm above the anal verge, located on the anterior wall of the rectum. The biopsy revealed that the nodule was also an NET (G2). However, the patient did not consent to abdominoperineal resection based on concerns for quality of life.

DIAGNOSES

Rectal NET with liver metastasis.

INTERVENTIONS

The patient underwent curative resection of liver metastasis. And, TEM was adopted to resect the primary tumor in rectum.

OUTCOMES

The patient has been disease-free for 2 years with a good quality of life and presents no local recurrence in the rectum.

LESSONS

TEM is an appropriate palliative operation for therapy of rectal NETs with distant metastases, especially for primary rectal NETs located in low rectal.

Diagnosis and Management of Rectal Neuroendocrine Tumors

The incidence of rectal neuroendocrine tumors (NETs) has increased by almost ten-fold over the past 30 years. There has been a heightened awareness of the malignant potential of rectal NETs. Fortunately, many rectal NETs are discovered at earlier stages due to colon cancer screening programs. Endoscopic ultrasound is useful in assessing both residual tumor burden after retrospective diagnosis and tumor characteristics to help guide subsequent management. Current guidelines suggest endoscopic resection of rectal NETs ≤10 mm as a safe therapeutic option given their low risk of metastasis. Although a number of endoscopic interventions exist, the best technique for resection has not been identified. Endoscopic submucosal dissection (ESD) has high complete and en-bloc resection rates, but also an increased risk of complications including perforation. In addition, ESD is only performed at tertiary centers by experienced advanced endoscopists. Endoscopic mucosal resection has been shown to have variable complete resection rates, but modifications to the technique such as the addition of band ligation have improved outcomes. Prospective studies are needed to further compare the available endoscopic interventions, and to elucidate the most appropriate course of management of rectal NETs.

Early Gastroenteropancreatic Neuroendocrine Tumors: Endoscopic Therapy and Surveillance

Neuroendocrine neoplasias (NEN) of the stomach, duodenum, pancreas, appendix, or rectum that are ≤1 cm in size as well as well-differentiated with World Health Organization grade 1 (G1) can be considered 'early' neuroendocrine tumors; they have a very good prognosis. Regarding prognosis, neuroendocrine tumors (NET) G1 must be distinguished from well-differentiated NET G2 and poorly differentiated neuroendocrine carcinomas (NEC) G3. NET are increasing, with a rise in the age-adjusted incidence in the USA by about 700% in the last 40 years. Earlier diagnosis of NET is one of the main epidemiological changes of clinically detected NEN. The general availability of high-resolution endoscopy and advanced radiological imaging techniques has contributed to a shift in the discovery to smaller-sized (≤10 mm) gastrointestinal and pancreatic NET and earlier tumor stages at diagnosis. Thus, screening colonoscopy is effective in the early diagnosis not only of colorectal adenomas and adenocarcinomas but also of rectal NET. Endoscopic resection is the treatment of choice in NET G1 of the stomach, duodenum (despite gastrinoma), and rectum that are ≤10 mm in size, do not infiltrate the muscularis propria (T1), and do not show angioinvasion (V0, L0). Similarly, histologically proven, early pancreatic NET G1 (≤10 mm) may be managed conservatively by regular surveillance. In contrast, small (≤1 cm) NET G1 of the jejunum or ileum are not 'early' tumors and have to be resected surgically with lymph node dissection.

Role of PD-L1 expression as a biomarker for GEP neuroendocrine neoplasm grading

Neuroendocrine neoplasms (NENs) are rare, heterogeneous and ubiquitous tumors commonly localized in the gastrointestinal tract, lung, and pancreas. The clinical behavior of NEN is highly unpredictable; in fact, low-grade cases can unexpectedly be associated with metastases. Currently, the 2010 WHO NEN classification employs histological differentiation and the proliferation index for grading tumors but fails to provide reliable prognostic and therapeutic indications. Therefore, there is an urgent need for a better characterization of G2/G3 NENs. Similar to several other tumors, NENs possess immune-escape mechanisms, but very little has yet been done to characterize this crucial aspect. There are no available data describing PD-L1 expression in these tumors. Here we provide, for the first time, evidence of PD-L1 tissue expression in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). PD-L1 expression was significantly associated with a high-grade WHO classification (G3) (P<0.001) but not with gender, primary site, or lymph node status. The PD-L1 positivity rate and signal intensity are directly correlated (P<0.001) with a grade increase from G1 to G3. In particular in G3 cases, we observed a dichotomy between the morphology (WD- and PD-NENs) and Ki67. Moreover, our study demonstrated a significant association with the grade and PD-L1 expression levels in immune-infiltrating cells (P<0.001). In particular, G3 tumors are characterized by strong PD-L1 expression in both the tumor and infiltrating immune cells (P<0.001), reflecting an unfavorable environment for T-cell-mediated tumor aggression. These findings suggest that NENs might acquire resistance to immune surveillance by upregulating PD-L1 and inhibiting peritumoral and intratumoral infiltrating lymphocytes. Here we demonstrate that PD-L1 is currently the best-known biomarker for G3 NENs, becoming the new gold standard for G3 NEN discrimination. Furthermore, pharmacological approaches using anti-PD-1 antibodies may become the logical choice for the treatment of G3 cases with a poor prognosis.

Carcinoid Heart Disease: Starting From Heart Failure

Carcinoid syndrome is the constellation of symptoms mediated by humoral factors produced by some carcinoid tumors. It consists primarily of vasomotor symptoms, gastrointestinal hypermotility, hypotension, and bronchospasm, due to the production and release of vasoactive substances. Carcinoid heart disease occurs in more than 50% of patients with carcinoid syndrome; in some cases, it represents the initial manifestation of the disease. We report the case of a 75-year-old woman with a metastatic neuroendocrine tumor admitted to the emergency room for fatigue and heart failure. Transthoracic echocardiography showed severe tricuspid and pulmonic regurgitation suggesting carcinoid heart disease. A hypervascular retroperitoneal mass was found on abdominal computed tomography, which seemed to arise from the mesenteric artery, anteriorly to the abdominal aorta. Unfortunately, our patient was neither a candidate for mass resection nor for cardiac surgery due to advanced metastatic disease and poor clinical condition. Additionally, we performed a systematic literature review of carcinoid heart disease focusing on typical echocardiographic findings.

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.

Short- and Long-term Outcomes of Laparoscopic Total Mesenteric Excision for Neuroendocrine Tumors of the Rectum

BACKGROUND

To our knowledge, no studies to date have assessed the short- and long-term outcomes of laparoscopic total mesenteric excision in patients with neuroendocrine tumors of the rectum.

OBJECTIVE

The purpose of this study was to investigate the short- and long-term outcomes of patients who underwent laparoscopic rectal resection plus total mesenteric excision for rectal neuroendocrine tumors at our institution.

DESIGN

This was a single center, retrospective study.

SETTINGS

The study was conducted at a tertiary care facility.

PATIENTS

Eight-two patients with neuroendocrine tumors who underwent rectal resection with total mesenteric excision, 77 laparoscopically, between June 2005 and August 2015 were included.

INTERVENTIONS

Laparoscopic rectal resection and total mesenteric excision were the study interventions.

MAIN OUTCOME MEASURES

Demographic characteristics and surgical and postoperative outcomes were measured.

RESULTS

Median tumor size was 8.8 mm (range, 3.0-35.0 mm); 63.6% of tumors were located in the lower rectum, with the median distance from the tumor to the anal verge being 50.0 mm (range, 20.0-130.0 mm). Anal preservation was achieved in all of the patients. Anastomotic leakage occurred in 5 patients (6.5%), but there were no deaths. Seventy-one patients (92.2%) had tumor invasion confined to the submucosa. Lymph node metastasis was present in 29 patients (37.7%), including 26 (33.8%) with perirectal and 5 (6.5%) with lateral lymph node metastasis. The median follow-up period in 59 patients was 42 months (range, 11-113 months), and the 3-year overall survival rate was 97.8%.

LIMITATIONS

The study was limited by its single-center, retrospective analysis.

CONCLUSIONS

Laparoscopic rectal resection with total mesenteric excision is safe in patients with rectal neuroendocrine tumors, with good short- and long-term outcomes. Because rectal neuroendocrine tumors are smaller and show superficial invasion, the rate of anal preservation may be high.

Frequent Presence of Lymphovascular Invasion in Small Rectal Neuroendocrine Tumors on Immunohistochemical Analysis

Rectal neuroendocrine tumors (RNETs) have become common in recent years and are good candidates for endoscopic resection (ER). To achieve clear resection margins, more advanced techniques such as endoscopic submucosal dissection, endoscopic submucosal resection with a ligation device, and cap-assisted endoscopic mucosal resection are available for ER. After ER, lymphovascular invasion (LVI) is regarded as an important predictor of nodal metastasis. Previous studies have shown that small RNETs with LVI were uncommon (0-8.3%). However, using immunohistochemical analysis, a recent study revealed the frequent occurrence of LVI in small RNETs in a systematic manner (46.7%). There is a possibility that the actual detection rate of LVI in small RNETs is not always evaluated accurately because of the limited detection sensitivity of conventional hematoxylin-eosin staining. In addition, the correlation between LVI detected using immunohistochemical analysis and the development of metastasis remains unclear. Further prospective studies are required to clarify the role of LVI detected using immunohistochemical analysis.

Rectal Neuroendocrine Tumor G1 with a Solitary Hepatic Metastatic Lesion

Rectal neuroendocrine tumor (NET) is a relatively rare tumor. NET is classified as G1, G2, or G3 according to the degree of mitosis or Ki-67 proliferation index, which reflect the malignant potential of the tumor, such as metastasis. Advanced cases with metastasis are indicated for chemotherapy treatment. However, the efficacy of chemotherapy is limited. Therefore, resection is considered, even in metastatic cases, if complete resection is possible. We herein report a case of small rectal NET discovered with hepatic metastasis classified as G1. The patient showed good progress with no recurrence after undergoing hepatectomy and endoscopic resection of rectal NET.

Somatostatin analogues in acromegaly and gastroenteropancreatic neuroendocrine tumours: past, present and future

Acromegaly is a hormonal disorder that arises when the pituitary gland secretes excess growth hormone (GH), which in turn stimulates a concomitant increase in serum insulin-like growth factor 1 (IGF-1) levels. Gastroenteropancreatic neuroendocrine tumours (GEP-NET) constitute a heterogeneous group of tumours that can secrete serotonin and a variety of peptide hormones that may cause characteristic symptoms known as carcinoid syndrome or other symptoms and hormonal hypersecretion syndromes depending on the tumour's site of origin. Current medical therapy for the treatment of acromegaly and GEP-NET involves the administration of somatostatin analogues that effectively suppress excess hormone secretion. After its discovery in 1979, octreotide became the first synthetic biologically stable somatostatin analogue with a short-acting formulation of octreotide introduced into clinical practice in the late 1980s. Lanreotide, another somatostatin analogue, became available in the mid-1990s initially as a prolonged-release formulation administered every 10 or 14 days. Long-acting release formulations of both octreotide (Sandostatin LAR and Novartis) and lanreotide (Somatuline Autogel, Ipsen), based on microparticle and nanoparticle drug-delivery technologies, respectively, were later developed, which allowed for once-monthly administration and improved convenience. First-generation somatostatin analogues remain one of the cornerstones of medical therapy in the management of pituitary and GEP-NET hormone hypersecretion, with octreotide having the longest established efficacy and safety profile of the somatostatin analogue class. More recently, pasireotide (Signifor), a next-generation multireceptor-targeted somatostatin analogue, has emerged as an alternative therapeutic option for the treatment of acromegaly. This review summarizes the development and clinical success of somatostatin analogues.

Lymphovascular invasion in more than one-quarter of small rectal neuroendocrine tumors

AIM

To identify the frequency, clinicopathological risk factors, and prognostic significance of lymphovascular invasion (LVI) in endoscopically resected small rectal neuroendocrine tumors (NETs).

METHODS

Between June 2005 and December 2015, 104 cases of endoscopically resected small (≤ 1 cm) rectal NET specimens at Hallym University Sacred Heart Hospital in Korea were retrospectively evaluated. We compared the detected rate of LVI in small rectal NET specimens by two methods: hematoxylin and eosin (H&E) and ancillary immunohistochemical staining (D2-40 and Elastica van Gieson); in addition, LVI detection rate difference between endoscopic procedures were also evaluated. Patient characteristics, prognosis and endoscopic resection results were reviewed by medical charts.

RESULTS

We observed LVI rates of 25.0% and 27.9% through H&E and ancillary immunohistochemical staining. The concordance rate between H&E and ancillary studies was 81.7% for detection of LVI, which showed statistically strong agreement between two methods (κ = 0.531, P < 0.001). Two endoscopic methods were studied, including endoscopic submucosal resection with a ligation device and endoscopic submucosal dissection, and no statistically significant difference in the LVI detection rate was detected between the two (26.3% and 26.8%, P = 0.955). LVI was associated with large tumor size (> 5 mm, P = 0.007), tumor grade 2 (P = 0.006). Among those factors, tumor grade 2 was the only independent predictive factor for the presence of LVI (HR = 4.195, 95%CI: 1.321-12.692, P = 0.015). No recurrence was observed over 28.8 mo regardless of the presence of LVI.

CONCLUSION

LVI may be present in a high percentage of small rectal NETs, which may not be associated with short-term prognosis.

Short- and long-term outcomes of endoscopic resection of rectal neuroendocrine tumours: analyses according to the WHO 2010 classification

OBJECTIVE

Although the World Health Organisation (WHO) defined a novel classification of gastroenteropancreatic neuroendocrine tumours (NETs) in 2010, indications for endoscopic resection of rectal NETs in the guidelines were based on evidence accumulated for carcinoid tumours defined by a previous classification. This study was designed to clarify indications for endoscopic resection of rectal NETs corresponding to the new WHO classifications.

MATERIAL AND METHODS

One hundred-seventy rectal NETs resected endoscopically from April 2001 to March 2012 were histologically re-classified according to the WHO 2010 criteria. The clinicopathological features of these lesions were analysed, and the short- and long-term outcomes of endoscopic resection were evaluated.

RESULTS

Of the 170 rectal NETs, 166 were histopathologically diagnosed as NET G1 and four as NET G2. Thirty-eight tumours (22.4%) were positive for lymphovascular invasion, a percentage higher than expected. Although the curative resection rate was low (65.3%), en bloc (98.8%) and complete (85.9%) resection rates were high. Modified endoscopic mucosal resection (88.0%) and endoscopic submucosal dissection (92.2%) resulted in significantly higher complete resection rates than conventional endoscopic mucosal resection (36.4%). No patient experienced tumour recurrence, despite the low curative resection rate.

CONCLUSION

Despite the low curative resection rate, prognosis after endoscopic resection of rectal NETs was excellent. Prospective large-scale, long-term studies are required to determine whether NET G2 and tumours >1 cm should be included in the indication for endoscopic resection and whether tumours with lymphovascular invasion can be followed up without additional surgery.

Heterogeneity of grade 3 gastroenteropancreatic neuroendocrine carcinomas: New insights and treatment implications

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are currently classified as grade (G) 1, G2 and G3, in accordance with the 2010 WHO classification. G1 and G2 are named neuroendocrine tumors (NETs) whereas G3 neuroendocrine carcinomas (NECs). While advanced G1 and G2 are usually treated with several different therapies, including somatostatin analogs, chemotherapy, interferon, molecular targeted agents, peptide receptor radionuclide therapy (PRRT) and liver-directed treatments, advanced G3 NECs are usually treated with a platinum-etoposide chemotherapy, trusting their clinical homogeneity is similar to that of small cell lung cancer. However, over the last years a number of reports suggested that 2010 WHO G3 GEP NECs are more heterogeneous than expected. Therefore, we critically reviewed the literature about this topic and reported pathological and clinical considerations on 2010 WHO G3 GEP NEC category proposing new sub-categories. Over the last five years, six studies specifically investigating large series of G3 GEP NECs have been published, including around 800 patients. Tumor morphology and Ki-67 Labeling Index (that will be mentioned as Ki-67 in this manuscript) combination has been reported as a tool to define two or even three subgroups of this category with different prognosis and potentially different therapeutic approach. Prospective trials are warranted to investigate if several types of therapy other than the platinum/etoposide chemotherapy can be effective in well differentiated GEP NEN with 21-55% Ki-67 and alkylating-based chemotherapy in poorly differentiated GEP NEN with 21-55% Ki-67.

Enhanced detection of lymphovascular invasion in small rectal neuroendocrine tumors using D2-40 and Elastica van Gieson immunohistochemical analysis

Rectal neuroendocrine tumor (RNET) lymphovascular invasion (LVI) is regarded as an important predictor of nodal metastasis after endoscopic resection (ER). However, little is known about the frequency of immunohistochemical detection of LVI in RNETs. This study was performed to establish the actual detection of LVI rate in RNETs ≤10 mm and to evaluate associated clinical outcomes. We retrospectively reviewed the records for 98 consecutive patients treated by ER with a total of 102 RNETs ≤10 mm. Tissue sections were labeled with hematoxylin–eosin (HE) stain, the D2‐40 monoclonal antibody to evaluate lymphatic invasion, and Elastica van Gieson (EVG) stain to detect venous invasion. LVI detection rate by HE versus immunohistochemical analysis was compared. Follow‐up findings and clinical outcomes were also evaluated for 91 patients who were followed for ≥12 months. Lymphatic and venous invasion were detected using HE staining alone in 6.9% and 3.9% of patients, respectively, whereas they were detected using D2‐40 and EVG staining in 20.6% and 47.1% of the patients, respectively. Thus, the LVI detection frequency using D2‐40 and EVG staining (56.9%) was significantly higher than with HE (8.8%). Two out of seven patients who required additional surgery had regional lymph node metastases. However, among the 84 patients who were followed up without surgery, no distant metastases or recurrences were detected. Compared with HE staining, immunohistochemical analysis significantly increased the frequency of LVI detection in RNETs ≤10 mm. However, the clinical impact of LVIs detected using immunohistochemical analysis remains unclear. Clarification of the actual role of LVI using immunohistochemical analysis requires a patient long‐term follow‐up and outcomes.

Molecular profiling of neuroendocrine malignancies to identify prognostic and therapeutic markers: a Fox Chase Cancer Center Pilot Study

BACKGROUND

The rarity of neuroendocrine malignancies limits the ability to develop new therapies and thus a better understanding of the underlying biology is critical.

METHODS

Through a prospective, IRB-approved protocol, patients with neuroendocrine malignancies underwent next-generation sequencing of their tumours to detect somatic mutations (SMs) in 50 cancer-related genes. Clinicopathologic correlation was made among poorly differentiated neuroendocrine carcinomas (NECs/poorly differentiated histology and Ki-67 >20%) and pancreatic neuroendocrine tumours (PanNETs/Ki67 ⩽20%) and non-pancreatic neuroendocrine tumours (NP-NETs/Ki67 ⩽20%).

RESULTS

A total of 77 patients were enrolled, with next-generation sequencing results available on 63 patients. Incidence of SMs was 83% (19 out of 23) in poorly differentiated NECs, 45% (5 out of 11) in PanNETs and 14% (4 out of 29) in NP-NETs. TP53 was the most prevalent mutation in poorly differentiated NECs (57%), and KRAS (30%), PIK3CA/PTEN (22%) and BRAF (13%) mutations were also found. Small intestinal neuroendocrine tumours (Ki67 <2%/n=9) did not harbour any mutations. Prevalence of mutations correlated with higher risk of progression within the previous year (32% (low risk) vs 11% (high risk), P=0.01) and TP53 mutation correlated with worse survival (2-year survival 66% vs 97%, P=0.003).

CONCLUSIONS

Poorly differentiated NECs have a high mutation burden with potentially targetable mutations. The TP53 mutations are associated with poor survival in neuroendocrine malignancies. These findings have clinical trial implications for choice of therapy and prognostic stratification and warrant confirmation.

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.

Endoscopic Resection for Small Rectal Neuroendocrine Tumors: Comparison of Endoscopic Submucosal Resection with Band Ligation and Endoscopic Submucosal Dissection

Background and Aims. There is no consensus so far regarding the optimal endoscopic method for treatment of small rectal neuroendocrine tumor (NET). The aim of this study was to compare treatment efficacy, safety, and procedure time between endoscopic submucosal resection with band ligation (ESMR-L) and endoscopic submucosal dissection (ESD). Methods. We conducted a prospective study of patients who visited Inha University Hospital for endoscopic resection of rectal NET (≦10 mm). Pathological complete resection rate, procedure time, and complications were evaluated. Results. A total of 77 patients were treated by ESMR-L (n = 53) or ESD (n = 24). En bloc resection was achieved in all patients. A significantly higher pathological complete resection rate was observed in the ESMR-L group (53/53, 100%) than in the ESD group (13/24, 54.2%) (P = 0.000). The procedure time of ESD (17.9 ± 9.1 min) was significantly longer compared to that of ESMR-L (5.3 ± 2.8 min) (P = 0.000). Conclusions. Considering the clinical efficacy, technical difficulty, and procedure time, the ESMR-L method should be considered as the first-line therapy for the small rectal NET (≤10 mm). ESD should be left as a second-line treatment for the fibrotic lesion which could not be removed using the ESMR-L method.

Metastatic rectal neuroendocrine tumor presenting as an inguinal mass: A case report and review of literature

•

Neuroendocrine tumors (NETs) are a heterogeneous and relatively rare group of neoplasms that often develop along the gastrointestinal tract.

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Rectal NETs are usually incidental findings on colonoscopy or present with metastatic disease.

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Treatment regimens for advanced metastatic rectal NETs are currently being developed.

Introduction

Neuroendocrine tumors (NET) are a heterogeneous group of rare carcinomas that most often manifest along the gastrointestinal tract. Some of these tumors have the ability to secrete vasoactive peptides and hormones.

Presentation of case

The present report describes the case of a previously healthy 52-year old man who presented with a painful right inguinal mass. Upon surgical exploration, a lymph node metastasis of a high-grade NET was found. Further investigations revealed a rectal NET with pulmonary, pelvic and penile metastases.

The patient was treated with 6 cycles of carboplatin and etoposide. Although initial follow-up imaging after 3 cycles of chemotherapy revealed stable disease, there was progression of the metastases after completion of systemic treatment. Second and third-line chemotherapy regimens were instituted along with pelvic and whole-brain radiation therapy extending the patient’s survival to 18 months after the initial diagnosis.

Discussion

This case highlights the aggressive nature high-grade NETs as described in the current literature. Treatment modalities of colorectal NETs include local excision for non-metastatic disease and systemic palliative chemotherapy for advanced disease. However, there are no controlled trials in favor of palliative chemotherapy.

Conclusion

Rectal NETs are rare tumors which often have an atypical presentation or present in advanced stages. Currently, surgical options exist for local disease while treatment modalities for more advanced disease is still under investigation.