Discrepancies between two alternative staging systems (European Neuroendocrine Tumor Society 2006 and American Joint Committee on Cancer/Union for International Cancer Control 2010) of neuroendocrine neoplasms of the pancreas. A study of 50 cases

Comparison of morphological features in lymph node metastasis between pancreatic neuroendocrine neoplasms and pancreatic ductal adenocarcinomas

BACKGROUND

Various studies have reported inconsistent results regarding the use of lymph node size for the prediction of metastasis in pancreatic cancer. Further, there is even less information in pNENs. Thus, the clinical accuracy and utility of using lymph node size to predict lymph node metastasis in pNENs has not been fully elucidated OBJECTIVES: This study aimed to examine differences in lymph node morphology between pancreatic neuroendocrine neoplasms (pNENs) and pancreatic ductal adenocarcinomas (PDACs) to create more accurate diagnostic criteria for lymph node metastasis.

METHODS

We assessed 2139 lymph nodes, 773 from pNEN specimens and 1366 from PDAC specimens, surgically resected at our institute between 1994 and 2016. We evaluated the number, shape, size, and presence of metastasis.

RESULTS

Sixty-eight lymph nodes from 16 pNEN patients and 109 lymph nodes from 33 PDAC patients were metastatic. There were more lymph nodes sampled per case in the PDAC group than in the pNEN group (31.8 vs. 18.0). Metastatic lymph nodes in pNEN patients were larger and rounder than those in PDAC patients (minor axis: 5.15 mm vs. 3.11 mm; minor axis/major axis ratio: 0.701 vs. 0.626). The correlation between lymph node size and metastasis was stronger in pNENs (r = 0.974) than in PDACs (r = 0.439).

CONCLUSIONS

Lymph node status and morphology are affected by differences in tumor histology. The lymph node minor axis is a reliable parameter for the prediction of lymph node metastasis and has more utility as a predictive marker in pNENs than in PDACs.

Systematic review of current prognostication systems for pancreatic neuroendocrine neoplasms

BACKGROUND

Pancreatic neuroendocrine neoplasms are a heterogenous group of rare tumors whose natural history remains poorly defined. Accurate prognostication of pancreatic neuroendocrine neoplasms is essential for guiding clinical decisions. This paper aims to summarize all the commonly utilized and recently proposed prognostication systems for pancreatic neuroendocrine neoplasms published in the literature to date.

METHODS

A systematic review of Pubmed, Scopus, and Embase databases, of the period from January 1, 2000-November 29, 2016, was conducted to identify all published articles reporting on prognostication systems of pancreatic neuroendocrine neoplasms.

RESULTS

A total of 23 articles were included in our review, and a total of 25 classification systems were identified. There were 2 modifications of the World Health Organization 2004 criteria, 4 modifications of the World Health Organization 2010 criteria, 2 modifications of the American Joint Committee on Cancer 2010 staging system, 3 modifications of the European Neuroendocrine Tumor Society 2006 tumor, node, metastasis staging system, 7 novel categorial classification systems, and 2 novel proposed continuous classifications. The most commonly included variables included age, size of tumor, presence of distant and lymph node metastases, Ki-67 index, and mitotic count.

CONCLUSION

Numerous prognostication systems have been proposed for pancreatic neuroendocrine neoplasms, of which the most commonly used systems presently include the World Health Organization 2010 criteria and the two tumor, node, metastasis staging systems by the European Neuroendocrine Tumor Society and the American Joint Commission on Cancer. However, prognostication systems for pancreatic neuroendocrine neoplasms continue to evolve with time as more prognostication factors are identified. More validation and comparative studies are needed to identify the most effective prognostication system.

Predictive Effect of the Total Number of Examined Lymph Nodes on N Staging and Survival in Pancreatic Neuroendocrine Neoplasms

OBJECTIVES

We aim to examine the predictive effect of the total number of examined lymph nodes on N stage and survival in pancreatic neuroendocrine neoplasms (pNENs) and to determine the optimal threshold.

METHODS

A pNENs data set from 2004 to 2013 was extracted from the Surveillance, Epidemiology, and End Result database. Multivariate logistic regression and Cox proportional hazards model were used to identify predictive factors associated with N stage and survival, respectively.

RESULTS

Totally, 1280 pNENs were analyzed. The 11 to 15 lymph nodes examined showed a strong association with the N1 stage (6-10 vs 11-15: odds ratio, 0.672; P = 0.042; 11-15 vs 16-20: odds ratio, 1.049; P = 0.840). However, it failed to show any survival benefit in pNENs with or without lymph node metastasis.

CONCLUSIONS

Examining at least 11 lymph nodes may be useful to accurately classify the N stage for pNENs.

Downregulation of SIRT6 is associated with poor prognosis in patients with non-small cell lung cancer

Objective

To explore the prognostic significance of nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase sirtuin-6 (SIRT6), encoded by the sirtuin 6 (SIRT6) gene, in a population of Chinese Han patients with non-small cell lung cancer (NSCLC).

Methods

Cancer tissues and normal lung tissues (>5 cm adjacent to cancer tissue) were collected from Chinese Han patients with NSCLC. Expression levels of SIRT6 and histone H3-acetyl K56 (H3K56), in cancer and normal lung tissues from patients with NSCLC, were detected by reverse-transcription polymerase chain reaction, Western blot and immunohistochemistry. Correlations between SIRT6 expression and various clinicopathologic features were investigated.

Results

Out of 86 patients included in the study, mRNA and protein SIRT6 levels were down-regulated in NSCLC tissue versus normal lung tissue, and SIRT6 levels were inversely correlated with H3K56 levels. Positive rates of SIRT6 were significantly correlated with degree of cell differentiation, TNM stage, lymph node metastasis, overall survival and metastasis-free survival.

Conclusion

Downregulation of SIRT6 expression may promote NSCLC malignancy in the Chinese Han population. SIRT6 may be a potential therapeutic target in Chinese Han patients with NSCLC.

Novel recurrence risk stratification of resected pancreatic neuroendocrine tumor

Radical surgical resection represents the only hope of cure for pancreatic neuroendocrine tumor (PanNET). Adjuvant therapy is rarely used because there is no evidence to distinguish patients with high recurrence risk. Here we investigated the recurrence feature of resected PanNET and established a novel risk stratification to predict its recurrence. We analyzed 505 PanNET patients who underwent R0 resection at our institute from January 2004 through May 2015. The median follow-up was 71months (range: 12months-143months), 129 patients (25.5%) experienced recurrence with median disease-free survival (mDFS) of 19months. Restricted cubic spline (RCS) functions revealed a positive, linear relationship between Ki-67 index and recurrence. Multivariate analysis showed T stage, N stage, insulinoma and Ki-67 index were independent predictors of recurrence (P < 0.05). Based on scores of these independent factors, we generated a recurrent-risk stage system with HCI of 0.806, superior to TNM stage (HCI 0.704) and grading system (HCI 0.706). Resected PanNET were classified into low risk (65.3%, mDFS not reached), intermediate risk (16.6%, mDFS 48months, 95%CI 26.5-73.4), high risk (13.3%, mDFS 24months, 95%CI 19.4-50.5) and very high risk (4.8%, mDFS 10months, 95%CI 6.9-13.0) (Hazard ratio: 2.650, 95%CI: 2.233-3.145, P < 0.001). This novel risk stratification thus identified PanNET patients of different recurrent-risk. Patients with very high recurrence risk may be suitable for post-operative clinical trials investigating adjuvant treatment.

Functional and non-functional pancreatic neuroendocrine tumours: ENETS or AJCC TNM staging system?

Background

There are currently 2 Tumour-Node-Metastasis (TNM) staging systems for pancreatic neuroendocrine tumours (p-NETs) - European Neuroendocrine Tumour Society (ENETS) and American Joint Committee on Cancer (AJCC). P-NETs being heterogeneous, we investigated the prognostic value of the 2 systems in p-NETs, as a whole, and more interestingly in functional and non-functional sub-groups separately, with a view to ascertaining any potential clinical benefits of using one system over the other.

Methods

Data from patients with surgically resected p-NETs were retrospectively reviewed. Kaplan-Meier method and Cox Regression proportional hazards model were used to analyse overall survival (OS) and prognostic predictors respectively.

Results

In the whole group of 165 patients, both TNM systems successfully discriminated OS differences when comparing stages I and II with stages III and IV (P<0.05); ENETS stage III patients had a significantly better OS than those in stage IV (P=0.003). Patients with functional p-NETs in ENETS stage II showed a statistically better OS than those in stages III and IV (P<0.05). For non-functional tumours, the AJCC staging system could effectively discriminate between the OS differences of patients in stage I with stages III and IV, or stage II with III and IV (P<0.05). Along with surgical intent and World Health Organisation (WHO) 2010 grade, both ENETS and AJCC staging systems were effective predictors of OS for different function-status p-NETs.

Conclusions

The ENETS system might have potential advantages when applied to all p-NETs and to the functional sub-group, while the AJCC system might be clinically more practical for non-functional p-NETs.

Validation and comparison between current prognostication systems for pancreatic neuroendocrine neoplasms: A single-institution experience with 176 patients

BACKGROUND

This article aims to validate and compare the performance of 6 prognostication systems-the World Health Organization 2010 grading criteria, the European Neuroendocrine Tumour Society and the American Joint Committee for Cancer staging systems, the Memorial Sloan Kettering Cancer Center staging and grading systems, as well as the Bilimoria criteria in a cohort of patients with pancreatic neuroendocrine neoplasms at a single institution.

METHODS

A retrospective review of 176 patients with histologically proven pancreatic neuroendocrine neoplasm was performed. The prognostic ability of the various prognostication systems for pancreatic neuroendocrine neoplasm was assessed by analyzing the homogeneity, discriminatory ability, monotonicity of gradient, and Akaike information criteria.

RESULTS

The 5-year overall survival for the 176 patients was 69% and 5-year recurrence-free survival in 119 patients who underwent curative resection was 78%. Comparison between the 6 prognostication systems demonstrated that the World Health Organization 2010 system had the lowest Akaike information criteria score and was hence the best prognostication system in predicting overall survival and recurrence-free survival rates in our cohort of patients. The European Neuroendocrine Tumour Society was superior to the American Joint Committee for Cancer in prognosticating overall survival rates for pancreatic neuroendocrine neoplasms, as there was a statistically significant difference in overall survival across the different stages when stratified by the European Neuroendocrine Tumour Society, while the use of the American Joint Committee for Cancer was limited to distinguishing between patients in stages I and II versus stages III and IV only.

CONCLUSION

All 6 prognostication systems were useful in the prognostication of pancreatic neuroendocrine neoplasm. The World Health Organization 2010 grading system was the best prognostication system in predicting both overall survival in our entire cohort of patients and recurrence-free survival in the subset of patients who underwent curative resection.

The ENETS/WHO grading system for neuroendocrine neoplasms of the gastroenteropancreatic system: a review of the current state, limitations and proposals for modifications

The understanding of neuroendocrine neoplasms has evolved significantly since their initial descriptions in the 1800s to early 1900s. In the gastroenteropancreatic system, this group of malignant tumors is subdivided into well and poorly differentiated neuroendocrine neoplasms based on morphologic, proliferative and biologic differences. However, it has become increasingly apparent that well-differentiated neuroendocrine tumors are not a homogeneous group. Attempting to better predict outcome of these tumors has been the motivation behind numerous proposed classification systems, the evolution of which culminated with the currently used system, the ENETS/WHO classification. Herein, we review the genesis of this classification system and some of its shortcomings. In addition, we discuss some of the most recent proposals that suggest modifications to the current system.

Expression of miRNA-26b in the diagnosis and prognosis of patients with non-small-cell lung cancer

OBJECTIVE

To investigate the correlation between miR-26b and non-small-cell lung cancer (NSCLC).

MATERIALS & METHODS

NSCLC tissues and normal lung tissues that were more than 7 cm adjacent from tumor were collected from 154 NSCLC patients. Additionally, 63 normal specimens from benign lung disease were selected as the control group. Real-time fluorescent quantitative PCR was used to detect miR-26b expression in tissues.

RESULT

miR-26b expression in NSCLC tissues was significantly lower than in other two types of tissues. Receiver operating characteristic curve analysis showed that the area under the curve was 0.856 with sensitivity and specificity of 79.9 and 79.4%, respectively. miR-26b expression was a risk factor for poor prognosis of NSCLC.

CONCLUSION

The expression of miR-26b is downregulated in NSCLC tissues, and it might be useful in the diagnosis and prognosis of NSCLC patients.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

Neuroendocrine Carcinomas of the Gastroenteropancreatic System: A Comprehensive Review

To date, empirical literature has generally been considered lacking in relation to neuroendocrine carcinomas (NECs), the highly malignant subgroup of neuroendocrine neoplasms. NECs are often found in the lungs or the gastroenteropancreatic (GEP) system and can be of small or large cell type. Concentrating on GEP-NECs, we can conclude that survival times are poor, with a median of only 4–16 months depending on disease stage and primary site. Further, this aggressive disease appears to be on the rise, with incidence numbers increasing while survival times are stagnant. Treatment strategies concerning surgery are often undecided and second-line chemotherapy is not yet established. After an analysis of over 2600 articles, we can conclude that there is indeed more empirical literature concerning GEP-NECs available than previously assumed. This unique review is based on 333 selected articles and contains detailed information concerning all aspects of GEP-NECs. Namely, the classification, histology, genetic abnormalities, epidemiology, origin, biochemistry, imaging, treatment and survival of GEP-NECs are described. Also, organ-specific summaries with more detail in relation to disease presentation, diagnosis, treatment and survival are presented. Finally, key points are discussed with directions for future research priorities.

Outcome of surgery for pancreatic neuroendocrine neoplasms

BACKGROUND

The incidence of pancreatic neuroendocrine neoplasms (pNEN) is increasing. This study aimed to evaluate predictors of overall survival and the indication for surgery.

METHODS

Data collected between October 2001 and December 2012 were analysed. Histological grading and staging was based on the classifications of the World Health Organization, the International Union Against Cancer and the European Neuroendocrine Tumour Society.

RESULTS

Some 310 patients (150 female, 48·4 per cent) underwent surgical resection. The final survival analysis included 291 patients. Five-year overall survival differed according to tumour grade (G): 91·0 per cent among 156 patients with pancreatic neuroendocrine tumours (pNET) G1, 70·8 per cent in 111 patients with pNET G2, and 20 per cent in 24 patients with pancreatic neuroendocrine carcinomas (pNEC) G3 (P < 0·001). Tumours graded G3 (hazard ratio (HR) 6·96, 95 per cent confidence interval 3·67 to 13·21), the presence of distant metastasis (HR 2·41, 1·32 to 4·42) and lymph node metastasis (HR 2·10, 1·07 to 4·16) were independent predictors of worse survival (P < 0·001, P = 0·004 and P = 0·032 respectively). Eight of 61 asymptomatic patients with pNEN smaller than 2 cm had tumours graded G2 or G3, and six of 51 patients had lymph node metastasis. Among patients with pNEC G3, the presence of distant metastasis had a significant impact on the 5-year overall survival rate: 0 per cent versus 43 per cent in those without distant metastasis (P = 0·036).

CONCLUSION

Neuroendocrine tumours graded G3, lymph node and distant metastasis are independent predictors of worse overall survival in patients with pNEN.

Staging accuracy of MR for pancreatic neuroendocrine tumor and imaging findings according to the tumor grade

PURPOSE

To investigate staging accuracy of MR for pancreatic neuroendocrine neoplasms (PNETs) and imaging findings according to the tumor grade.

MATERIALS AND METHODS

Our study consisted of 39 patients with PNET G1 (n = 24), PNET G2 (n = 12), and pancreatic neuroendocrine carcinoma (PNEC) (n = 3). All underwent preoperative MRI. Two radiologists retrospectively reviewed MR findings including tumor margin, SI on T2WI, enhancement patterns, degenerative change, duct dilation, and ADC value. They also assessed T-stage, N-stage, and tumor size. Statistical analyses were performed using Chi square tests, ROC analysis, and Fisher's exact test.

RESULTS

Specific findings for PNEC or PNET G2 were ill-defined borders (P = 0.001) and hypo-SI on venous- and delayed-phase (P = 0.016). ADC value showed significant difference between PNET G1 and G2 (P = 0.007). The Az of ADC value for differentiating PNET G1 from G2 was 0.743. Sensitivity and specificity were 70% and 86%. Accuracy for T-staging was 77% (n = 30) and 85% (n = 33), and for N-staging was 92% (n = 36) and 87% (n = 34) with moderate agreement. T-stage showed significant difference according to tumor grade (P < 0.001), although there was no significant difference in tumor size or N-stage.

CONCLUSION

Ill-defined borders and hypo-SI on venous- and delayed-phase imaging are common findings of higher grade PNET, and ADC value is helpful for differentiating PNET G1 from G2. MR is useful for preoperative evaluation of T-, N-stage. Tumor size of PNET and T-stage showed significant difference according to tumor grade.

A single institution's 26-year experience with nonfunctional pancreatic neuroendocrine tumors: a validation of current staging systems and a new prognostic nomogram

OBJECTIVE

To validate the 2010 American Joint Committee on Cancer (AJCC) and 2006 European Neuroendocrine Tumor Society (ENETS) tumor staging systems for pancreatic neuroendocrine tumors (PanNETs) using the largest, single-institution series of surgically resected patients in the literature.

BACKGROUND

The natural history and prognosis of PanNETs have been poorly defined because of the rarity and heterogeneity of these neoplasms. Currently, there are 2 main staging systems for PanNETs, which can complicate comparisons of reports in the literature and thereby hinder progress against this disease.

METHODS

Univariate and multivariate analyses were conducted on the prognostic factors of survival using 326 sporadic, nonfunctional, surgically resected PanNET patients who were cared for at our institution between 1984 and 2011. Current and proposed models were tested for survival prognostication validity as measured by discrimination (Harrel's c-index, HCI) and calibration.

RESULTS

Five-year overall-survival rates for AJCC stages I, II, and IV are 93% (88%-99%), 74% (65%-83%), and 56% (42%-73%), respectively, whereas ENETS stages I, II, III, and IV are 97% (92%-100%), 87% (80%-95%), 73% (63%-84%), and 56% (42%-73%), respectively. Each model has an HCI of 0.68, and they are no different in their ability to predict survival. We developed a simple prognostic tool just using grade, as measured by continuous Ki-67 labeling, sex, and binary age that has an HCI of 0.74.

CONCLUSIONS

Both the AJCC and ENETS staging systems are valid and indistinguishable in their survival prognostication. A new, simpler prognostic tool can be used to predict survival and decrease interinstitutional mistakes and uncertainties regarding these neoplasms.

Neuroendocrine tumors of the pancreas: current concepts and controversies

In the past decade, the clinico-pathologic characteristics of neuroendocrine tumors (NETs) in the pancreas have been further elucidated. Previously termed "islet cell tumors/carcinomas" or "endocrine neoplasms", they are now called pancreatic NETs (PanNETs). They occur in relatively younger patients and may arise anywhere in the pancreas. Some are associated with von Hippel-Lindau, MEN1, and other syndromes. It is now widely recognized that, with the exception of tumorlets (minute incipient neoplasms) that occur in some syndromes like MEN1, all PanNETs are malignant, albeit low-grade, and although they have a protracted clinical course and overall 10-year survival of 60-70 %, even low-stage and low-grade examples may recur and/or metastasize on long-term follow-up. Per recent consensus guidelines adopted by both European and North American NET Societies (ENETS and NANETs) and WHO-2010, PanNETs are now graded and staged separately, unlike previous classification schemes that used a combination of grade, stage, and adjunct prognosticators in an attempt to define "benign behavior" or "malignant" categories. For staging, the ENETs proposal may be more applicable than CAP/AJCC, which is based on the staging of exocrine tumors. Current grading of PanNETs is based on mitotic activity and ki-67 index. Other promising prognosticators such as necrosis, CK19, c-kit, and others are still under investigation. It has also been recognized that PanNETs have a rather wide morphologic repertoire including oncocytic, pleomorphic, ductulo-insular, sclerosing, and lipid-rich variants. Most PanNETs are diagnosed by fine needle aspiration biopsy, in which single, monotonous plasmacytoid cells with fair amounts of cytoplasm and distinctive neuroendocrine chromatin are diagnostic. Molecular alterations of PanNETs are also very different than that of ductal or acinar tumors. Loss of expression of DAXX and ATRX proteins has been recently identified in 45 %. Along with these improvements, several controversies remain, including grading, value of current cutoff ranges, and the best methods for counting ki-67 index (manual count by computer-captured image may be the most practical for the time being). More important is the controversial use of the term "carcinoma", which was previously employed in WHO-2004 only for invasive and metastatic cases but has now been made synonymous with grade 3 group of tumors. It is becoming clear that grade 3 group comprises two distinct categories: (1) differentiated but proliferatively more active tumors which typically have ki-67 indices in the 20-50 % range and (2) true poorly differentiated NE carcinomas as defined in the lung, with ki-67 typically >50 %. Further studies are needed to address these controversial aspects of PanNETs.

Histopathology of gastrointestinal neuroendocrine neoplasms

Gastrointestinal neuroendocrine neoplasms (GI-NENs) arise from neuroendocrine cells distributed mainly in the mucosa and submucosa of the gastrointestinal tract. In 2010, the World Health Organization (WHO) classification of NENs of the digestive system was changed, categorizing these tumors as grade 1 neuroendocrine tumor (NET), grade-2NET, neuroendocrine carcinoma (large- or small-cell type), or mixed adenoneuroendocrine carcinoma (MANEC). Such a classification is based on the Ki-67 index and mitotic count in histological material. For the accurate pathological diagnosis and grading of NENs, it is important to clearly recognize the characteristic histological features of GI-NENs and to understand the correct method of counting Ki-67 and mitoses. In this review, we focus on the histopathological features of GI-NENs, particularly regarding biopsy and cytological diagnoses, neuroendocrine markers, genetic and molecular features, and the evaluation of the Ki-67 index and mitotic count. In addition, we will address the histological features of GI-NEN in specific organs.