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

A novel predictive model based on preoperative blood neutrophil-to-lymphocyte ratio for survival prognosis in patients with gastric neuroendocrine neoplasms

PURPOSE

Evaluate the predictive value of the preoperative blood neutrophil-to-lymphocyte ratio (NLR) on the clinical outcomes of patients with gastric neuroendocrine neoplasms (g-NENs) after radical surgery.

RESULTS

The NLR was significantly higher in patients with g-NENs than in matched normal volunteers (P < 0.05). A higher blood NLR was not significantly associated with clinical characteristics (all P > 0.05). According to the multivariate analysis, the NLR was an independent prognostic factor of RFS and OS. Nomograms, including the NLR, Ki-67 index and lymph node ratio, had superior discriminative abilities to predict clinical outcomes. The recurrence rate was 37% (55/147). The median time to recurrence was 9 months; 48 (87%) patients experienced recurrence within the first 2 years. Both the NLR and Ki-67 index were correlated with liver metastases (both P < 0.05) and were also negatively correlated with recurrence time (both P < 0.05).

MATERIALS AND METHODS

We enrolled 147 patients who were diagnosed with g-NENs and underwent radical surgery. Receiver operating characteristic curve analysis was used to identify the optimal value for blood NLR. Univariate and multivariate survival analysis were used to identify prognostic factors for g-NENs. A nomogram was adopted to predict RFS and OS after surgery.

CONCLUSIONS

As an independent prognostic factor for g-NENs, blood NLR can improve the predictability of RFS and OS. We recommend that g-NEN patients with a high blood NLR or high Ki-67 index undergo surveillance during the first month and then every 3 months for 2 years post-surgery.

Obturator Canal Lymph Node Metastasis from Rectal Carcinoid Tumors: Total Mesorectal Excision May Be Insufficient

BACKGROUND

Optimal surgical treatment for small early rectal carcinoids is controversial. Large tumors (greater than 2 cm) and those with imaging evidence of lymph node metastasis are generally treated by low anterior resection (LAR) with total mesorectal excision (TME). We first observed and reported that midgut carcinoid with extensive mesenteric lymphadenopathy often develops alternated lymphatic drainage pathways. We hypothesize that rectal carcinoids have the same potential to develop alternated lymphatic pathways outside the mesorectal envelope, which allows tumor deposits to be missed by traditional TME.

METHODS

Twenty-two consecutive rectal carcinoid surgical patient charts were reviewed to determine if alternated lymphatic drainage occurred and resulted in extra-mesorectal metastasis. We attempted to identify any risk factor(s) that may lead to developing such alternated lymphatic drainage pathways.

RESULTS

Thirteen patients underwent initial LAR with TME (13/22, 59 %) and nine underwent a staged debulking for locoregional residual disease or regional/distant metastasis after previous resection (9/22, 41 %). Fourteen (14/22, 64 %) underwent radio-guided surgery in attempt to achieve a higher level of pelvic/distant metastatic disease detection and debulking. Six patients (6/22, 27 %) had obturator canal lymph node metastases confirmed histologically.

CONCLUSIONS

Based on our study, at least 27 % of rectal carcinoid patients may have extra-mesorectal metastasis that would be missed by the traditional TME. Radio-guided surgery can identify and remove such metastasis. The effect of having such extra-mesorectal metastasis and its surgical removal on long-term survival has yet to be determined.

The Clinicopathologic Features and Treatment of 607 Hindgut Neuroendocrine Tumor (NET) Patients at a Single Institution

The clinicopathologic features of hindgut neuroendocrine tumor (NET) as well as the treatment outcomes are not well known. There are currently no published data on treatment outcomes for patients with metastatic hindgut NET. The aim of this study was to conduct a comprehensive analysis of clinicopathologic features, treatments and survival in hindgut NET patients. Among patients who were pathologically diagnosed with hindgut NET at Samsung Medical Center between March 2001 and February 2015, 607 were analyzed in this study. Hindgut NETs were defined as NETs that originated from the transverse and distal colon, rectum, and anus. Primary sites included 81 colon (13.3%) and 526 rectum (86.7%). According to the WHO classification, 578 patients (95.2%) had grade 1 NETs, 17 (2.8%) grade 2 NETs, and 12 (2.0%) had neuroendocrine carcinoma (NEC). Forty-two patients (6.9%) had extensive disease, while the majority (93.1%, 565 patients) only exhibited localized disease. The 5- and 10-year survival rates of 565 localized NET patients were 98.1% and 95.3%, respectively. The median OS in 42 patients with extensive disease was 24.8 months (95% CI, 10.7-38.8). Among 565 patients with localized disease, the majority (484 patients, 85.7%) were treated with endoscopic procedure by gastroenterologists. For 42 patients with extensive disease, 17 patients were managed by supportive care, 3 by concurrent chemoradiotherapy (CCRT), and 22 by systemic therapy. Among these 22 patients, 12 patients received only first-line therapy, 8 had second-line, and only 2 patients had third-line therapy. As first-line chemotherapy, the most commonly used regimens were etoposide plus cisplatin (N = 7) and long acting octreotide (N = 7). During treatment courses, the most commonly used regimen was long-acting octreotide. The median OS in 22 metastatic NET patients receiving systemic therapy was 19.3 months (95% CI, 3.2-35.3). Multivariate analysis in all 607 hindgut NETs patients suggested that the extent and the primary site of disease were significant independent prognostic factors for long term survival. This analysis provides useful information about the clinicopathologic features, treatments and survival outcomes for hindgut NET patients.

Hindgut Neuroendocrine Neoplasia

Neuroendocrine neoplasias (NENs) consist of a spectrum of tumors which can originate throughout the body, behave in a variety of different ways but are characterized by a similar histological appearance. This article reviews the classification, staging, diagnosis and treatment of Hindgut Neuroendocrine Neoplasias.

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.

Excellent prognosis following endoscopic resection of patients with rectal neuroendocrine tumors despite the frequent presence of lymphovascular invasion

BACKGROUND

Endoscopic resection (ER) has been increasingly used for the treatment of rectal neuroendocrine tumors (NETs); however, only limited data are available on its long-term outcomes. This study analyzed the long-term outcomes of rectal NETs treated by ER and characterized potential risk factors for metastasis in these cases, with emphasis on lymphovascular invasion.

METHODS

We retrospectively analyzed the clinicopathological features and outcomes of 86 patients with 90 rectal NETs who had been treated by ER. Lymphovascular invasion was reevaluated using elastic-staining and double-staining immunohistochemistry.

RESULTS

En bloc resection with tumor-free margins was achieved in 87 lesions (96.7%). The median tumor size was 5 mm (range 2-13), and all the lesions were confined to the submucosal layer. The Ki-67 index was less than 3% in all the lesions, which were therefore classified as NET G1. Elastic-staining and double-staining immunohistochemistry revealed the presence of lymphatic and venous invasion in 23 (25.6%) and 35 lesions (36.7%), respectively. Collectively, lymphatic and/or vascular invasion was identified in 42 lesions (46.7%). All cases were followed up without additional surgery, and no metastasis or recurrence was detected during the median follow-up period of 67.5 months.

CONCLUSIONS

This study showed an excellent long-term prognosis following ER of patients with rectal NETs, confirming that ER is a valid treatment option for small rectal NETs. The present study also revealed highly prevalent lymphovascular invasion even in minute rectal NETs; this observation raises a question regarding its significance as a risk factor for metastasis.

Glutaminases in slowly proliferating gastroenteropancreatic neuroendocrine neoplasms/tumors (GEP-NETs): Selective overexpression of mRNA coding for the KGA isoform

Glutamine (Gln) is a crucial metabolite in cancer cells of different origin, and the expression and activity of different isoforms of the Gln-degrading enzyme, glutaminase (GA), have variable implications for tumor growth and metabolism. Human glutaminases are encoded by two genes: the GLS gene encodes the kidney-type glutaminases, KGA and GAC, while the GLS2 gene encodes the liver-type glutaminases, GAB and LGA. Recent studies suggest that the GAC isoform and thus high GAC/KGA ratio, are characteristic of highly proliferating tumors, while GLS2 proteins have an inhibitory effect on tumor growth. Here we analyzed the expression levels of distinct GA transcripts in 7 gastroenteropancreatic neuroendocrine tumors (GEP-NETs) with low proliferation index and 7 non-neoplastic tissues. GEP-NETs overexpressed KGA, while GAC, which was the most abundant isoform, was not different from control. The expression of the GLS2 gene showed tendency towards elevation in GEP-NETs compared to control. Collectively, the expression pattern of GA isoforms conforms to the low proliferative capacity of GEP-NETs encompassed in this study.

Surgical approaches for liver metastases in carcinoid tumors

Liver is the commonest site for metastasis in patients with neuroendocrine tumors (NETs); it occurs in 45-95% of patients. Available treatment options include surgical resection, liver transplantation, chemotherapy and biotherapy. Surgery is the gold standard for curative therapy. Typically, a multidisciplinary approach is a cornerstone for decision making while dealing with this aggressive disease. This review will focus on the performance and safety of open, laparoscopic, and liver transplant surgical approaches in NETs patients with liver metastases.

Dilemmas in Endoscopic Management of Rectal Neuroendocrine Tumors: A Case-Based Discussion

Rectal neuroendocrine tumors are uncommon neoplasms that historically were regarded as having an indolent course. Due to the widespread use of screening colonoscopy neuroendocrine tumors of the rectum are identified with increasing frequency. More recent literature has suggested that rectal neuroendocrine tumors may progress in a more malignant fashion than previously believed. In this case-based discussion we present management dilemmas, analyze current guidelines, and highlight the role of endoscopic ultrasound, endoscopic resection, and surgery.

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.

A case of very well-differentiated adenocarcinoma with carcinoid tumor in the ascending colon

Malignant tumors with mixed glandular and neuroendocrine characteristics with at least 30% of each component are classified as mixed adenoneuroendocrine carcinoma (MANEC) by the World Health Organization 2010 classification. We report here a case of very well-differentiated adenocarcinoma accompanied by carcinoid tumor, categorized as MANEC. A 41-year-old Japanese man was clinically diagnosed with ascending colon cancer and underwent right hemicolectomy. Using an immunohistologic technique, the pathologic diagnosis was very well-differentiated adenocarcinoma accompanied by carcinoid tumor and marked eosinophil infiltration, which was categorized as MANEC. By immunohistochemical analysis, tumor cells of the carcinoid component exhibited very low proliferation activity. Our case was thought to be MANEC without high malignant potential. MANEC as per the World Health Organization 2010 classification seems to include tumors with diverse grades of malignancy, and it might need to have subclassifications according to the malignancy potential of the tumor cells.

Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies

Ki67 index is now an essential part of classification of pancreatic neuroendocrine tumors. However, its adaptation into daily practice has been fraught with challenges related to counting methodology. In this study, three reviewers used four counting methodologies to calculate Ki67 index in 68 well-differentiated pancreatic neuroendocrine tumors: (1) 'eye-ball' estimation, which has been advocated as reliable and is widely used; (2) automated counting by image analyzer; (3) manual eye-counting (eye under a microscope without a grid); and (4) manual count of camera-captured/printed image. Pearson's correlation (R) was used to measure pair-wise correlation among three reviewers using all four methodologies. Average level of agreement was calculated using mean of R values. The results showed that: (1) 'eye-balling' was least expensive and fastest (average time <1 min) but had poor reliability and reproducibility. (2) Automated count was the most expensive and least practical with major impact on turnaround time (limited by machine and personnel accessibility), and, more importantly, had inaccuracies in overcounting unwanted material. (3) Manual eye count had no additional cost, averaged 6 min, but proved impractical and poorly reproducible. (4) Camera-captured/printed image was most reliable, had highest reproducibility, but took longer than 'eye-balling'. In conclusion, based on its comparatively low cost/benefit ratio and reproducibility, camera-captured/printed image appears to be the most practical for calculating Ki67 index. Although automated counting is generally advertised as the gold standard for index calculation, in this study it was not as accurate or cost-effective as camera-captured/printed image and was highly operator-dependent. 'Eye-balling' produces highly inaccurate and unreliable results, and is not recommended for routine use.

The p53 network as therapeutic target in gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are heterogeneous and especially the midgut tumors currently lack effective therapy options. Actionable driver mutations as therapeutic targets are rare. Subtype specific data concerning regulatory mechanisms or epigenetic aberrations are necessary for novel clinical trials. Although the p53 protein itself is rarely mutated in GEP-NENs, epigenetic and regulatory aberrations interfere with the p53 network activity and might function as s target for novel therapeutic approaches. In this review we analyze the current knowledge about the p53 network in GEP-NENs and discuss three possible strategies that include recovering p53 function, enforcing apoptosis by genotoxic stress induction and restoring silenced gene function, based on in vitro, in vivo and clinical data.

Surgical management and outcome of rectal carcinoids in a university hospital

Background

Rectal carcinoids are an uncommon entity comprising only 1%–2% of all rectal tumors. Rectal carcinoids are frequently diagnosed during colonoscopy, but management after polypectomy is still controversial. The aims of this study were to review the surgical procedures for rectal carcinoids and to compare the outcomes of patients after different treatment modalities in a university hospital in Hong Kong.

Methods

All rectal carcinoids diagnosed between January 2003 and September 2012 were reviewed retrospectively, including clinicopathological characteristics, their management, and surgical outcomes.

Results

There were 54 patients with a median age of 60 years, and 32 were males (59.3%). All patients underwent colonoscopy, and the most had rectal bleeding (53.7%). Two patients were diagnosed incidentally in the surgical specimens of rectal tissues. Eighteen patients were diagnosed to have rectal carcinoids after snaring polypectomy, and no further intervention was required. Twenty-five patients had local resection either by means of transanal resection or transanal endoscopic operation. Radical resection was performed in seven patients in which one had T3N1 disease and the others did not have any lymph node metastasis.

In the median follow-up of 30 months (10–108 months), there was no recurrence in the “incidental” or post-polypectomy group. However, two patients with transanal resection and two patients with radical resection developed hepatic metastases after 13–24 months post-treatment. The 5-year overall survival was 100% in patients having snaring polypectomy only, 83% for those with local resection, and 63% in patients who underwent radical surgery (p = 0.04).

Conclusions

Our data suggested that that local resection was an effective treatment for small rectal carcinoids and generally brought about good oncological and surgical outcomes. For larger tumors, radical resection seemed to provide acceptable oncological outcomes. Regular surveillance with colonoscopy and endorectal ultrasound is highly recommended for high-risk patients for long-term management. By sharing our experience, we hope to provide more evidence on the management on rectal carcinoids which, together with evidence from further studies, may guide us in the long-term management of these patients in the future.

Catheter-based treatments for hepatic metastases from neuroendocrine tumors

OBJECTIVE

The purpose of this article is to present our experience in treating patients with hepatic metastases from a neuroendocrine primary malignancy.

CONCLUSION

The tumor and patient characteristics, vascular access, and features of treatment all play a role in the long-term management of patients with metatastic neuroendocrine tumors. Routine prophylactic measures are recommended to reduce the frequency and severity of crisis events related to hormone release in patients with neuroendocrine tumors.

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.

Endoscopically identified well-differentiated rectal carcinoid tumors: impact of tumor size on the natural history and outcomes

BACKGROUND

There is a paucity of data pertaining to the natural history and outcomes of patients with well-differentiated rectal carcinoids.

OBJECTIVE

To correlate endoscopic size with the natural history and outcome.

DESIGN

Retrospective study.

SETTING

Single tertiary referral center.

PATIENTS

Eighty-seven patients with endoscopically identified well-differentiated rectal carcinoid tumors.

INTERVENTION

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Prevalence of metastasis at diagnosis, disease progression, and survival.

RESULTS

Metastasis was present at diagnosis in 3%, 66%, and 73% of tumors measuring ≤10 mm, 11 to 19 mm, and ≥20 mm, respectively. Metastasis was predicted with 100% sensitivity and 87% specificity using an endoscopic lesion size ≥9 mm. In patients without identified metastasis, 64% were identified during screening colonoscopy. Within this select cohort, subsequent metastasis was discovered only at distant extra pelvic sites, in 1.6%, 50%, and 100% of patients with tumors initially measuring ≤10 mm, 11 to 19 mm, and ≥20 mm, respectively. The carcinoid related 5- and 10-year survival rates for locally confined disease were 96%. The corresponding survival rates for local and advanced metastatic disease were 60% and 35%, respectively.

LIMITATIONS

Subjective estimation of tumor size, mitotic index or Ki-67 labeling index not reported, and lack of formal and standardized baseline staging algorithm and surveillance program.

CONCLUSIONS

The clinical behavior of 11- to 19-mm tumors appears to mimic that of larger (>20 mm) lesions with respect to the presence of metastasis at diagnosis and disease progression. Therefore, if local therapy is contemplated, we propose to make a distinction between ≤10-mm and 11- to 19-mm tumors, favoring an aggressive staging and management protocol for 11- to 19-mm carcinoid tumors.

Silencing of UCHL1 by CpG promoter hyper-methylation is associated with metastatic gastroenteropancreatic well-differentiated neuroendocrine (carcinoid) tumors

BACKGROUND

Well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors with varying metastatic potential. The underlying molecular basis for metastasis by GEP-NETs remains undefined.

METHODS

Quantitative PCR and immunohistochemistry (IHC) staining for ubiquitin carboxyl-terminal esterase L1 (UCHL1) gene and protein expression was performed on a group of localized and metastatic well-differentiated GEP-NET samples acquired from a prospectively maintained tissue bank. The ability of extent of UCHL1 IHC staining to differentiate localized and metastatic tumors was compared with Ki-67 index.

RESULTS

Among 46 total samples, UCHL1 expression at both the gene and protein level was significantly greater among localized GEP-NETs compared with metastatic tumors and metastases (p < 0.001). Hypermethylation of the UCHL1 promoter was commonly observed among metastatic primary tumors and metastases (those with the lowest UCHL1 expression) but not among localized tumors (p < 0.001). Poor staining (<50 %) for UCHL1 was observed in 27 % of localized tumors compared with 87 % of metastatic tumors (p = 0.001). The presence of <50 % staining for UCHL1 was 88 % sensitive and 73 % specific for identifying metastatic disease. In contrast, there was no association between Ki-67 index and metastatic disease. In multivariable analysis, only UCHL1 staining <50 % [odds ratio (OR) 24.5, p = 0.035] and vascular invasion (OR 38.4, p = 0.03) were independent risk factors for metastatic disease at the time of initial surgery.

CONCLUSIONS

Loss of UCHL1 expression by CpG promoter hypermethylation is associated with metastatic GEP-NETs. Extent of UCHL1 staining should be explored as a potentially clinically useful adjunct to Ki-67 index in evaluating GEP-NETs for aggressive features.

Surveillance strategy for rectal neuroendocrine tumors according to recurrence risk stratification

BACKGROUND/AIM

Rectal neuroendocrine tumors (NETs) have been increasing in incidence. However, the recommendations for disease surveillance after tumor resection have not been well established. We evaluated the long-term outcomes of rectal NETs and surveillance strategies according to recurrence risk stratification.

METHODS

From January 2000 to July 2011, 188 patients diagnosed with rectal NETs were included in this study. Patient characteristics, treatment methods, recurrence rates, risk factors of recurrence, and surveillance schedules were analyzed.

RESULTS

The male-to-female ratio was 1.29:1 and the mean age at diagnosis was 50.6 years. The mean tumor size was 6.5 (range 1-30) mm. A total of 144 patients (76.6 %) were treated with endoscopic resection, and 44 patients (23.4 %) were treated with surgical resection as the initial treatment. During the follow-up period, ten patients (5.3 %) had disease recurrence, including one case of local recurrence and nine cases of recurrence at a distant site. Tumor size of >10 mm, invasion of the muscularis propria, increased mitotic index, lymphovascular invasion, and regional lymph node metastases were statistically significant predictors of recurrence by univariate analysis. Among the 152 patients without risk factors of recurrence, only one patient who underwent transanal resection had a local recurrence at 15 months after surgery.

CONCLUSION

Our patients with rectal NETs showed favorable clinical outcomes and had a low rate of recurrence. Intensive surveillance with endoscopy or imaging study may not be required in patients without risk factors for recurrence.

Long-term outcome of patients with locally resected high- and low-risk rectal carcinoid tumors

BACKGROUND

Tumor size and lymphovascular invasion are known high-risk factors for lymph node and distant metastasis in patients with rectal carcinoid tumors. However, the optimal treatment for these tumors remains controversial.

AIM

The aim of this paper is to compare the outcome of local or radical resection between patients with high-risk (tumor size >10 mm or lymphovascular invasion) disease and those with low-risk (tumor size ≤10 mm, no lymphovascular invasion) disease.

METHODS

Patients with rectal carcinoid tumors treated between January 1990 and March 2010 were identified retrospectively and classified into low- and high-risk groups.

RESULTS

In total, 83 patients with rectal carcinoid tumors were included, 53 (64%) of whom were identified as low-risk and 30 (36%) as high-risk. Local resection was performed in 50 (60%) low-risk and 24 (29%) high-risk patients, and postoperative recurrence was observed in one (1%) of the high-risk patients who underwent local resection and one (11%) who underwent radical resection. No recurrence was observed in the low-risk group. Kaplan-Meier analysis of the patients who underwent local resection revealed that the 10-year disease-free survival rate was 100% in the low-risk group and 83.3% in the high-risk group.

CONCLUSIONS

There was no significant difference in outcome between local and radical resection.

Rare tumors of the rectum. Narrative review

Most rectal neoplasms are adenocarcinomas, but there is a small percentage of tumors which are of other histological cell lines such as neuroendocrine tumors, sarcomas, lymphomas and squamous cell carcinomas, which have special characteristics and different treatments. We have reviewed these rare tumors of the rectum from a clinical and surgical point of view.

Rectal adenocarcinoma resection specimen with an incidental carcinoid in the resection margin

Three cases of incidental carcinoid tumors have been identified in the surgical margin of rectal adenocarcinoma resection specimens. In all cases the rectal carcinoids exhibited low-risk features, such as a tumor size <10 mm, no muscularis propria invasion and no lymph node involvement. No further excision was conducted and the three cases were followed up for 38, 26 and 14 months, respectively. No regional or distant rectal carcinoid recurrence was identified. Occasionally this is inevitable in order to achieve a positive resection margin for the microcarcinoid during the surgical treatment of another malignancy. However, such carcinoids are usually low-risk and behave less aggressively than same-site adenocarcinomas. Thus, it appears reasonable to avoid further excision in patients who are undergoing a rectal adenocarcinoma resection that exhibits a positive margin for low-risk carcinoid tumor.

Rectal carcinoids: a systematic review

BACKGROUND

Rectal carcinoids are increasing in incidence worldwide. Frequently thought of as a relatively benign condition, there are limited data regarding optimal treatment strategies for both localized and more advanced disease. The aim of this study was to summarize published experiences with rectal carcinoids and to present the most current data.

METHODS

Following PRISMA guidelines, an electronic literature search performed of PubMed, Medline, Embase, and the Cochrane Library using the terms "rectum" or "rectal" AND "carcinoid" over a 20-year study period from January 1993 to May 2013. Non-English-language studies, animal studies, and studies of fewer than 100 patients were excluded. Study end points included demographic information, tumor features, intervention and outcomes. All included articles were quality assessed.

RESULTS

Using the search parameters and exclusions as outlined above, a total of 14 articles were identified for detailed analysis. The quality of articles was low/moderate for all included scoring 9 to 17 of 27. The articles included 4,575 patients diagnosed with a rectal carcinoid. Approximately 80% of tumors were <10 mm, 15% 11-20 mm, and 5% >20 mm. Eight percent of patients presented with regional lymph node metastases, and 4% presented with distant metastases. Tumor size >10 mm, and muscular and lymphovascular invasion are independently associated with an increased risk of metastases. The 5-year survival was 93% in patients presenting with localized disease and 86% overall.

CONCLUSIONS

Small tumors up to 10 mm without any adverse features can be treated with endoscopic or local excision. The treatment of carcinoids between 10 and 20 mm is still contentious, but those up to 16 mm without adverse feature are suitable for local/endoscopic excision followed by careful histopathological assessment. Those >20 mm or with adverse features require radical surgery with mesorectal clearance in suitable patients.

Gastroenteropancreatic neuroendocrine neoplasms: Clinicopathologic characteristics and their correlation with prognosis

AIM: To analyze the clinicopathologic characteristics of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) and their correlation with prognosis.

METHODS: Clinical data for 43 patients diagnosed pathologically with GEP-NEN in Harbin Medical University Cancer Hospital from April 2007 to April 2013 were retrospectively analyzed. Survival analysis was performed by Kaplan-Meier method. The relationship between clinicopathologic characteristics and prognosis was analyzed using the Log-rank test. Independent risk factors for prognosis were analyzed by multivariate Cox regression analysis.

RESULTS: The mean age was 57.5 years, with a male-to-female ratio of 2.91:1. The most common site was stomach (19 cases, 44.19%). There were 2 cases of functional GEP-NEN (one case of glucagonoma and another case of carcinoid syndrome). Of the 43 patients, 14 received postoperative drug therapy. There were 22 deaths in 43 patients (52.38%) and one case (2.38%) was lost to follow-up. The 1- and 3-year survival rates were 70.2% and 36.9%, with a median overall survival (OS) of 16.0 months. Univariate analysis showed that tumor size (≥ 5 cm), depth of invasion, lymph node metastasis, distant metastasis and pathological grades of NEC (neuroendocrine carcinoma) and MANEC (mixed adenoneuroen docrine carcinoma) could affect the patient's prognosis (P < 0.05 for all). Age, gender, smoking, drinking, family history of cancer, surgical approach and postoperative drug therapy were not significantly associated with prognosis. Multivariate analysis showed that lymph node metastasis, distant metastasis and pathological type were independent risk factors.

CONCLUSION: The stomach is the most common primary site of GEP-NEN, and GEP-NEN lacks specific clinical manifestations. Lymph node metastasis, distant metastasis and pathological type are independent risk factors.

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

BACKGROUND AND AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Long term outcomes of neuroendocrine carcinomas (high-grade neuroendocrine tumors) of the colon, rectum, and anal canal

INTRODUCTION AND AIM

Neuroendocrine carcinomas (NEC) of the large intestine are rare and aggressive neoplasms. This study was designed to review the experience at a single institution and analyze the outcomes to improve our understanding of these tumors.

METHODS

The patients with NEC (high-grade neuroendocrine tumor) of the colon, rectum, and anal canal were identified from June 1993 to April 2011. Clinical features studied were patient demographics, presenting symptoms, tumor location, tumor stage, treatment status and length of follow-up.

RESULTS

Twenty-five patients were identified. Stages of the diseases were I (n=5), II (n=1), III (n=10) and IV (n=9). Locations of the tumors were: colon (36%); rectum (28%) and anal canal (36%). Rectal bleeding (36%) and pain (32%) were the most common symptoms but 16% of patients were asymptomatic. Among the patients with local or locally advanced disease, only five patients had surgery alone. The remainder of the patients underwent chemotherapy with/without radiation. Mean follow-up was 33.7 ± 8.4 months after diagnosis. NEC of the large bowel and anal canal has very distinctive pathologic features and a very poor prognosis. More than one third of the patients with NEC had metastatic disease at the time of diagnosis. When these tumors are in an advanced stage none of the treatment modalities impact on survival.

CONCLUSION

The present study showed the poor prognosis of these rare tumors.

A 92-gene cancer classifier predicts the site of origin for neuroendocrine tumors

A diagnosis of neuroendocrine carcinoma is often morphologically straight-forward; however, the tumor site of origin may remain elusive in a metastatic presentation. Neuroendocrine tumor subtyping has important implications for staging and patient management. In this study, the novel use and performance of a 92-gene molecular cancer classifier for determination of the site of tumor origin are described in a series of 75 neuroendocrine tumors (44 metastatic, 31 primary; gastrointestinal (n=12), pulmonary (n=22), Merkel cell (n=10), pancreatic (n=10), pheochromocytoma (n=10), and medullary thyroid carcinoma (n=11)). Formalin-fixed, paraffin-embedded samples passing multicenter pathologist adjudication were blinded and tested by a 92-gene molecular assay that predicts tumor type/subtype based upon relative quantitative PCR expression measurements for 87 tumor-related and 5 reference genes. The 92-gene assay demonstrated 99% (74/75; 95% confidence interval (CI) 0.93-0.99) accuracy for classification of neuroendocrine carcinomas and correctly subtyped the tumor site of origin in 95% (71/75; 95% CI 0.87-0.98) of cases. Analysis of gene expression subsignatures within the 92-gene assay panel showed 4 genes with promising discriminatory value for tumor typing and 15 genes for tumor subtyping. The 92-gene classifier demonstrated excellent accuracy for classifying and determining the site of origin in tumors with neuroendocrine differentiation. These results show promise for use of this test to aid in classifying neuroendocrine tumors of indeterminate primary site, particularly in the metastatic setting.

Quality of life, resource utilisation and health economics assessment in advanced neuroendocrine tumours: a systematic review

Neuroendocrine tumours (NET) are often diagnosed at an advanced stage when the prognosis is poor for patients, who often experience diminished quality of life (QoL). As new treatments for NET become available, it is important to characterise the associated outcomes, costs and QoL. A comprehensive search was performed to systematically review available data in advanced NET regarding cost of illness/resource utilisation, economic studies/health technology assessment and QoL. Four rounds of sequential review narrowed the search results to 22 relevant studies. Most focused on surgical procedures and diagnostic tools and contained limited information on the costs and consequences of medical therapies. Multiple tools are used to assess health-related QoL in NET, but few analyses have been conducted to assess the comparative impact of available treatment alternatives on QoL. Limitations include English language and the focus on advanced NET; ongoing terminology and classification changes prevented pooled statistical analyses. This systematic review suggests a lack of comparative economic and outcomes data associated with NET treatments. Further research on disease costs, resource utilisation and QoL for patients with advanced NET is warranted.

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

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

Imaging features of carcinoid tumors of the gastrointestinal tract

OBJECTIVE

Recent studies have provided a better understanding of the biologic behavior of gastrointestinal carcinoid tumors. This article focusing on imaging of gastrointestinal carcinoids will emphasize epidemiology, molecular biology, taxonomy, histopathology, and management.

CONCLUSION

Gastrointestinal carcinoids are a biologically heterogeneous group of tumors, with variable clinical presentation and biologic behavior. Imaging can play an important role in multidisciplinary identification and management of this disease.

Factors associated with lymph node metastasis in radically resected rectal carcinoids: a systematic review and meta-analysis

BACKGROUND

Although various guidelines regarding neuroendocrine tumors were released, treatment for rectal neuroendocrine tumors with size between 1 and 2 cm has not been explicitly elucidated. The determinant factor of the choice between endoscopic resection and radical surgery is whether lymph node involvement exists.

AIM

This study aims to explore factors associated with lymph node involvement in rectal neuroendocrine tumors by conducting a meta-analysis.

METHODS

A broad literature research of Pubmed, Embase&Medline, and The Cochrane Library was performed, and systematic review and meta-analysis about factors associated with lymph node involvement were conducted.

RESULTS

Seven studies were included in this meta-analysis. Tumor size > 1 cm (odds ratio (OR) 6.72, 95% confidence interval (CI) [3.23, 14.02]), depth of invasion (OR 5.06, 95% CI [2.30, 11.10]), venous invasion (OR 5.92, 95% CI [2.21, 15.87]), and central depression (OR 3.00, 95% CI [1.07, 8.43]) were significantly associated with lymph node involvement.

CONCLUSION

The available clinical evidence suggests that tumor size > 1 cm, invasion of muscularis properia, venous invasion, and central depression could be risk factors of lymph node involvement, while other factors reported by few studies need further research.

Endoscopic resection for gastrointestinal neuroendocrine tumors

Gastrointestinal (GI) and neuroendocrine tumors (NETs) can be treated by mini-invasive endoscopic resection when localized in the superficial layers of the bowel wall and their size is <20 mm. Endoscopic diagnosis of NETs is usually incidental or suspected after clinical, laboratory or imaging findings. Endoscopic mucosal resection is the most commonly used technique for NET removal, endoscopic submucosal dissection is indicated in selected cases, while papillectomy is feasible for ampullary lesions. Histopathologic assessment of the resection margin (circumferential and deep) is important for staging. Incidence of endoscopic mucosal resection-/endoscopic submucosal dissection-related complications for removal of GI NETs are similar to those reported for other GI lesions. Endoscopic follow-up is based on histopathologic characteristics of the resected NETs and its site. NETs >20 mm in size, with penetration of the muscle layer and/or serosa are at high risk for metastases and surgical approach is recommended when feasible.

Proposal for a standardized pathology report of gastroenteropancreatic neuroendocrine tumors: prognostic significance of pathological parameters

Background

There is confusion in the diagnosis and biological behaviors of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), because of independently proposed nomenclatures and classifications. A standardized form of pathology report is required for the proper management of patients.

Methods

We discussed the proper pathological evaluation of GEP-NET at the consensus conference of the subcommittee meeting for the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. We then verified the prognostic significance of pathological parameters from our previous nationwide collection of pathological data from 28 hospitals in Korea to determine the essential data set for a pathology report.

Results

Histological classification, grading (mitosis and/or Ki-67 labeling index), T staging (extent, size), lymph node metastasis, and lymphovascular and perineural invasion were significant prognostic factors and essential for the pathology report of GEP-NET, while immunostaining such as synaptophysin and chromogranin may be optional. Furthermore, the staging system, either that of the 2010 American Joint Cancer Committee (AJCC) or the European Neuroendocrine Tumor Society (ENETS), should be specified, especially for pancreatic neuroendocrine neoplasms.

Conclusions

A standardized pathology report is crucial for the proper management and prediction of prognosis of patients with GEP-NET.

Consensus guidelines for the management and treatment of neuroendocrine tumors

Neuroendocrine tumors are a heterogeneous group of tumors originating in various anatomic locations. The management of this disease poses a significant challenge because of the heterogeneous clinical presentations and varying degrees of aggressiveness. The recent completion of several phase 3 trials, including those evaluating octreotide, sunitinib, and everolimus, demonstrate that rigorous evaluation of novel agents in this disease is possible and can lead to practice-changing outcomes. Nevertheless, there are many aspects to the treatment of neuroendocrine tumors that remain unclear and controversial. The North American Neuroendocrine Tumor Society published a set of consensus guidelines in 2010, which provided an overview for the treatment of patients with these malignancies. Here, we present a set of consensus tables intended to complement these guidelines and serve as a quick, accessible reference for the practicing physician.

Targeted therapies in neuroendocrine tumors (NET): clinical trial challenges and lessons learned

In the past 3 years, we have witnessed the completion of four randomized phase III studies in neuroendocrine tumors and the approval of two new drugs, everolimus and sunitinib, for the treatment of patients with well-differentiated pancreatic neuroendocrine tumors. These studies demonstrate a shift from case series and single-arm studies toward prospective, randomized controlled clinical trials and evidence-based therapy in the neuroendocrine tumor field. However, the clinical development of these agents also highlights the potential challenges awaiting other new drugs in this area. Herein, we discuss the strengths and weaknesses of the most recent phase II and phase III neuroendocrine tumor studies and discuss how limitations inherent in current trial design can lead to potential pitfalls. We also discuss how trial design can be improved, with the hope of increasing the number of drugs successfully developed to treat patients with neuroendocrine tumors.

Gastroenteropancreatic neuroendocrine tumors: role of imaging in diagnosis and management

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of neoplasms that arise from cells of the diffuse neuroendocrine system and are characterized by a wide spectrum of clinical manifestations. All NETs are potentially malignant but differ in their biologic characteristics and the probability of metastatic disease. The pathologic classification of these tumors relies on their proliferation and differentiation. In the past decades, several nomenclatures have been proposed to stratify neuroendocrine tumors, but the World Health Organization classification is the one that is most widely accepted and used. The diagnosis of neuroendocrine tumor relies on clinical manifestation, laboratory parameters, imaging features, and tissue biomarkers in a biopsy specimen. With improved understanding of the natural history and lesion biology, management of GEP-NETs has also evolved. Although surgery remains the only potentially curative therapy for patients with primary GEP-NETs, other available treatments include chemotherapy, interferon, somatostatin analogs, and targeted therapies. Recent improvements in both morphologic and functional imaging methods have contributed immensely to patient care. Morphologic imaging with contrast agent-enhanced multidetector computed tomography and magnetic resonance imaging is most widely used for initial evaluation and staging of disease in these patients, whereas functional imaging techniques are useful both for detection and prognostic evaluation and can change treatment planning.

Heterogeneity in signaling pathways of gastroenteropancreatic neuroendocrine tumors: a critical look at notch signaling pathway

The molecular pathogenesis of gastroenteropancreatic neuroendocrine tumors is largely unknown. We hypothesize that gastroenteropancreatic neuroendocrine tumors are heterogeneous with regard to these signaling pathways and these differences could have a significant impact on the outcome of clinical trials. We selected 120 well-differentiated neuroendocrine tumors including tumors originating in pancreas (n=74), ileum (n=31), and rectum (n=15). Immunohistochemistry was performed on tissue microarrays using the following antibodies: NOTCH1, HES1, HEY1, pIGF1R, and FGF2. Gene profiling study was performed by using human genome U133A 2.0 array and data were analyzed. The gene profiling results were selectively confirmed by using quantitative reverse-transcription PCR. Initial immunohistochemical analysis showed NOTCH1 was uniformly expressed in rectal neuroendocrine tumors (100%), a subset of pancreatic neuroendocrine tumors (34%), and negative in ileal neuroendocrine tumors. Similarly, a downstream target of NOTCH1, HES1 was preferentially expressed in rectal neuroendocrine tumors (64%), a subset of pancreatic neuroendocrine tumors (10%), and uniformly negative in ileal neuroendocrine tumors. Messenger RNAs for NOTCH1, HES1, and HEY1 were 2.32-, 2.44-, and 2.39-folds, respectively, higher in rectal neuroendocrine tumors as compared with ileal neuroendocrine tumors. Global gene expression profiling showed 95 genes were differentially expressed in small intestinal vs rectal neuroendocrine tumors, with changes as high as 50-fold. These genes were concentrated in several signal transduction pathways including cancer endocrine pathway and cell growth/proliferation pathway. The differential expression of selected genes including ISL LIM homeobox 1, cathepsin B, glucagon, and tryptophan hydroxylase 1 were confirmed by qPCR and immunohistochemistry. Our results confirm the heterogeneity in signaling pathways of gastroenteropancreatic neuroendocrine tumors. NOTCH1 inhibitors are unlikely to provide benefit in ileal neuroendocrine tumors; conversely, their efficacy in rectal neuroendocrine tumors needs further study. Further analysis of signaling pathways is critical for designing clinical trials in gastroenteropancreatic neuroendocrine tumors.

Clinical and prognostic features of rectal neuroendocrine tumors

BACKGROUND

Rectal neuroendocrine tumors (NETs) are among the most common NETs. The aim was to validate European Neuroendocrine Tumor Society (ENETS)/North American Neuroendocrine Tumor Society (NANETS) staging and grading systems with regard to clinical outcomes.

METHODS

A comprehensive database was constructed from existing databases of the Mount Sinai Division of Gastrointestinal Pathology and the Carcinoid Cancer Foundation. Analysis was performed on 141 patients identified with rectal NETs seen at Mount Sinai Hospital between 1972 and 2011.

RESULTS

The median age was 52.7 years; 43% were males. Average tumor size was 0.88 cm. NETs <1 cm accounted for 75.6% of the tumors. Stage I, II, III and IV accounted for 79.4, 2.8, 5.0 and 12.8% of the tumors, respectively. G1 tumors accounted for 88.1%, G2 8.3% and G3 3.6%. Of G1 tumors, 94.6% were stage I and 5.4% were stage IV. The median survival time for all 141 patients was 6.8 years (range, 0.8-34.7 years). The overall 5-year survival rate was 84.4%. The 5-year survival rates for patients in stages I-IV were 92.7, 75.0, 42.9 and 33.2%, respectively. The 5-year survival rates for patients with G1-G3 tumors were 87.7, 47.6 and 33.3%, respectively. Univariate analysis of increased survival showed significance for lower stage, lower grade, smaller size, absence of symptoms and endoscopically treated tumors. Multivariate analysis showed that stage alone was statistically significant as the strongest predictor of survival.

CONCLUSION

The results of our study validated ENETS/NANETS guidelines for staging and grading of rectal NETs in the US setting of a tertiary referral center. Staging according to ENETS/NANETS guidelines should be used in the treatment algorithm rather than size alone.

Everolimus plus octreotide long-acting repeatable in patients with colorectal neuroendocrine tumors: a subgroup analysis of the phase III RADIANT-2 study

INTRODUCTION

The incidence of colorectal neuroendocrine tumors (NETs) is increasing, and patients with this disease have particularly poor prognoses. Treatment options are limited, and survival times have not improved in the past decade.

METHODS

A post hoc analysis of the efficacy and tolerability of everolimus plus octreotide long-acting repeatable (LAR) was conducted in patients with colorectal NETs enrolled in the phase III RAD001 in Advanced Neuroendocrine Tumors, Second Trial (RADIANT-2) study. The primary endpoint (progression-free survival [PFS]), secondary endpoints (including objective response rate), and safety were assessed.

RESULTS

Patients with colorectal NETs receiving everolimus plus octreotide LAR had a significantly longer median PFS (29.9 months; n = 19) than did those receiving placebo plus octreotide LAR (6.6 months; n = 20). Everolimus plus octreotide LAR treatment also significantly reduced the risk for disease progression (hazard ratio: 0.34; 95% confidence interval: 0.13-0.89; p = .011). Although no objective responses were observed, tumor shrinkage was more frequently noted in the everolimus plus octreotide LAR arm than in the placebo plus octreotide LAR arm (67% vs. 37%, respectively). The combination of everolimus plus octreotide LAR was generally well tolerated by patients with colorectal NETs; rash and stomatitis were the most commonly reported adverse events.

CONCLUSIONS

Everolimus plus octreotide LAR treatment had significant benefits and improved outcomes for patients with advanced colorectal NETs compared with placebo plus octreotide LAR treatment. Results of this exploratory analysis are consistent with those reported from the RADIANT-2 primary analysis. These findings support additional investigations of everolimus plus octreotide LAR in patients with colorectal NETs.

Colonic and rectal NET's

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

Neuroendocrine tumors of the colon and rectum: prognostic relevance and comparative performance of current staging systems

BACKGROUND

With increasing interest in neuroendocrine tumors (NETs), three staging systems for NETs of the colon and rectum have been published. Their prognostic relevance has not been examined and compared in an independent clinical database.

METHODS

From the National Cancer Database (NCDB), 5457 patients diagnosed with colorectal neuroendocrine tumor (CRNETs) between 1998 and 2002 were staged according to the staging systems from (1) European Neuroendocrine Tumor Society (ENETS, 2006; n = 1537); (2) American Joint Committee on Cancer (AJCC, 2009; n = 1140); and (3) location-specific staging systems from the Surveillance Epidemiology and End Results (SEER, 2008; n = 942). Stage-stratified overall survival (OS) and Cox-specific concordance indices were calculated for each system. Independent prognostic factors were identified by multivariate analysis.

RESULTS

Five-year OS for stage I, II, III, and IV CRNETs as defined by the ENETS staging system were 90.8, 77.3, 53.1, and 14.8 %, respectively. For well-differentiated CRNETs, the 5-year OS for stage I, II, III, and IV as defined by the AJCC staging system were superior: 90.6, 83.9, 64.8, and 24.9 %, respectively. Both staging systems had a concordance index of 0.72. After specifying location in the colon versus rectum, all three systems demonstrated acceptable performance. Histologic grade was a significant independent predictor of OS not currently incorporated in the staging systems.

CONCLUSIONS

The three staging systems showed comparable prognostic stratification of CRNETs, while the AJCC and ENETS systems are the most parsimonious. The current analysis supports the use of the AJCC for well-differentiated disease and ENETS systems for all CRNETs until there is further evidence for modification.

Pathology - grading and staging of GEP-NETs

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) constitute a heterogeneous group of neoplasms. In the last few decades, due to a substantial rise in incidence and prevalence, GEP-NETs have been included among the most common tumours of the gastrointestinal tract. Diagnosis could be challenging and a significant number of patients present with metastatic or unresectable disease. The development of appropriate tools for standardised prognostic stratification and the introduction of effective target therapies have opened new horizons for planning tailored surgical or medical management and follow-up programs for these complex neoplasms. An overview on the GEP-NETs' diagnostic and prognostic criteria proposed by the recently published WHO classification and ENETS and UICC TNM staging systems is presented, focussing on their impact on the clinical and therapeutical approaches.

Carcinoid and other neuroendocrine tumors of the colon and rectum

Neuroendocrine tumors (NETs) are found throughout the intestinal tract and arise from the Kulchitsky cells located in the crypts of Lieberkühn. They are classified by site of origin and by degree of differentiation, with well-differentiated lesions representing those tumors formerly referred to as carcinoid tumors. The focus of this review is NETs of the appendix, colon, and rectum. The clinical presentation of these tumors is dependent on the primary site and many are discovered incidentally, either during screening or during the investigation of nonspecific abdominal complaints. Treatment is primarily via surgical removal as the response to chemotherapy has been traditionally poor. A noted exception to this has been with treatment of the carcinoid syndrome, which occurs almost exclusively in patients with liver metastases and is due to the release of bioactive peptides and amines directly into the systemic circulation. The use of somatostatin congeners to block the release of these substances has greatly ameliorated the devastating symptoms of this condition. Postresection follow-up is advocated, but specific recommendations are lacking an evidentiary basis. NETS, particularly those of the small bowel, colon, and appendix, are seen in association with other synchronous or metachronous malignancies, often of the gastrointestinal tract. However, the utility of subsequent screening and surveillance is unproven.