Radical surgical treatment of neuroendocrine tumors of the appendix in children - a Polish multicenter study

INTRODUCTION

The aim of the study was to examine management of pediatric appendiceal neuroendocrine tumors (ANETs) in Poland.

METHODS

Records of 27 patients with ANET diagnosed incidentally after appendectomy in the last decade.

RESULTS

Well-differentiated NET G1/G2 was diagnosed in 25 and well-differentiated neuroendocrine carcinoma G3 in 2 patients. Extended surgery was performed primarily in one instance and secondarily in 10 patients (right hemicolectomy in 9, ileocecal resection in 1) without adjuvant chemotherapy. Follow-up range was 1-121 months. Recurrence after secondary surgery was observed in 1 (3.7%) patient.

CONCLUSIONS

Applying ENETS guidelines resulted in 100% overall survival of patients with NET.

Lights and darks of neuroendocrine tumors of the appendix

INTRODUCTION

Neuroendocrine tumors of the appendix are a relatively frequent type of neuroendocrine tumor, usually detected incidentally after appendectomy. Almost all small slow-growing G1 tumors with no risk factors are cured with appendectomy while the rare and aggressive G3 carcinomas may represent a challenge in terms of management and often lead to a poor outcome. In the middle of the spectrum, a number of tumors present with in-between features and sometimes no clear-cut guidance emerges from the literature for directing the management and follow-up of these patients.

EVIDENCE ACQUISITION

A meticulous review of the literature on neuroendocrine tumors of the appendix, including the recommendations published by the relevant international societies.

EVIDENCE SYNTHESIS

The literature on the neuroendocrine tumors of the appendix appears to be inhomogeneous. Likely this occurs as a consequence of a number of factors, including the mostly retrospective nature of the available data, the heterogeneous records of the same, and some peculiar aspects of the appendiceal neuroendocrine tumors, with evidence of considerable biological and clinical differences in terms of epidemiology, management, and prognosis from the less aggressive tumors to the most aggressive cancers. In particular, some situations concerning tumors in the middle of the biological and clinical spectrum are still poorly defined.

CONCLUSIONS

There are some persisting "grey areas" with regard to the characterization and the clinical management of neuroendocrine tumors of the appendix. An increasing awareness of the biological and clinical aspects of this disease and new, ideally prospective, focused studies might help and clarify some relevant issues that are not fully elucidated yet and could increase the solidity of the guidance for the management and the follow-up of the patients.

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.

Tumor staging but not grading is associated with adverse clinical outcome in neuroendocrine tumors of the appendix: a retrospective clinical pathologic analysis of 138 cases

Appendiceal neuroendocrine neoplasms (NENs) are rare and usually incidentally discovered. Most cases are clinically indolent, although the rare aggressive ones are poorly predictable. The aim of this study was to test the applicability and prognostic significance of the new World Health Organization (WHO) classification and to test the several pathologic features and TNM staging systems (American Joint Committee on Cancer and European Neuroendocrine Tumor Society) in these tumors. A multi-institutional retrospective series of 138 appendiceal NENs was selected on the basis of the availability of both pathologic material and clinical information, including follow-up data. All cases were reviewed to record pathologic features and to apply year 2000 and 2010 WHO classifications, as well as European Neuroendocrine Tumor Society and American Joint Committee on Cancer TNM stages. Clinical and pathologic characteristics were compared with disease outcome by contingency, univariate, and multivariate survival analyses. Although up to one third of cases presented several malignancy-associated pathologic features, only 4 patients died of the disease. Adverse outcome was significantly associated with extramural extension (including mesoappendix), well-differentiated carcinoma diagnosis (2000 WHO classification), pT3-4 stage, older age, and presence of positive resection margins, but not with tumor size, mitotic or proliferative indexes, and, consequently, 2010 WHO grading. In the appendix, at variance with midgut/hindgut NENs, the 2000 WHO classification performs better than the grading-based 2010 WHO scheme and, together with tumor stage, is the most relevant parameter associated with clinical aggressiveness.

Pathology reporting of neuroendocrine tumors: essential elements for accurate diagnosis, classification, and staging

Much recent debate has focused on the optimal classification of epithelial neuroendocrine tumors (NETs). Multiple different systems of terminology, grading, and staging have been proposed, and some systems combine elements of grade and stage into a single prognostic classification. Recently, national and international consensus groups have attempted to standardize the classification of NETs, especially for those arising in the gastrointestinal tract and pancreas. Furthermore, the recognition that common classification criteria (such as proliferative rate) span multiple different systems allows the basic data necessary to predict outcome and tailor therapy to be included in pathology reports, even though a single uniform system of terminology may remain elusive. Formal tumor-node-metastasis (TNM)-based staging systems also have been developed recently, and advances in the treatment of some NETs (pancreatic in particular) are pointing towards the need to assess therapeutic biomarkers in routine practice. This review will present the most widely used systems for classifying, grading, and staging NETs and will summarize the recommendations for the data to be included in standard pathology reports of these uncommon tumors.

Neuroendocrine tumors of the appendix in children and adolescents

BACKGROUND

Neuroendocrine tumors (NET) of the appendix in children and adolescents are rare and mostly detected postoperatively by a histopathological examination. Since the malignant potential of these tumors remains unclear, therapeutic recommendations are not evidence based. The Society of Pediatric Oncology and Hematology (GPOH) has prospectively registered and followed children with appendical NET since 1997 (GPOH-MET trial). The objective of this study was to critically evaluate the therapeutic recommendations for appendical NET in children.

PROCEDURE

Clinical data of 237 children with appendical NET were prospectively analyzed.

RESULTS

The mean age at presentation was 13.0 years, while the mean follow-up time was 2.9 (0.0-12.8) years. The majority of tumors (70.9%) were located at the apex, and were smaller than or equal to 10 mm (72.7%). Tumor size was directly correlated with age. A second operation or primary lymph node sampling was done in 25.3% (N = 60) of the patients, and infiltration of the lymph nodes by tumor cells was found in nine of these patients (15%). All 237 patients are alive without tumor symptoms.

CONCLUSIONS

ROC analysis and subsequent calculations identified a tumor size of >15 mm as the optimal cut-off point for the prediction of metastatic spread into the lymph system, with a sensitivity of 77.8% and a specificity of 66.7%. Therefore, secondary right hemicolectomy in completely removed appendical NET is recommended only in tumors >15 mm in size. For incompletely removed tumors ≤15 mm a local follow-up resection with lymph node sampling is recommended.

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.

[Surgical strategies for accidental detection of appendix carcinoids]

Carcinoids (neuroendocrine tumors NET) of the appendix are rare tumors and even today mostly detected only postoperatively by histopathology following operations for acute appendicitis or other abdominal procedures. Most NETs of the appendix are located at the tip of the appendix, less than 2 cm in size and non-metastasizing. Secondary right hemicolectomy with lymph node dissection bears a considerable risk of complications compared to simple appendectomy. To decide upon secondary surgery histopathological risk factors, such as grading, invasion of the mesoappendix, and tumor type in addition to tumor localization and size should be taken into consideration. Up to 20% of NETs of the appendix are associated with various neoplasms of the gastrointestinal tract. Follow-up examination should therefore also consider both appendix carcinoids and synchronous or metachronous neoplasms of the gastrointestinal tract.

Conundrums and Caveats in Neuroendocrine Tumors of the Pancreas

Pancreatic neuroendocrine tumors (Pan-NETs) are the second most common epithelial neoplasm of the pancreas after ductal adenocarcinoma. They can be clinically defined as functional, nonfunctional, and hereditary. This review addresses typical and atypical pathologic features of Pan-NETs, with a focus on practical issues involved in differential diagnosis, immunohistochemical work-up, intraoperative frozen section interpretation, sources of diagnostic errors, and classification. The diagnosis of a Pan-NET requires analysis of all available clinical and radiographic information and pathologic characteristics of the tumor, and it is crucial to understand the clinical impact of the pathologic interpretation.

The pathologic classification of neuroendocrine tumors: a review of nomenclature, grading, and staging systems

Neuroendocrine tumors (NETs) arise in most organs of the body and share many common pathologic features. However, a variety of different organ-specific systems have been developed for nomenclature, grading, and staging of NETs, causing much confusion. This review examines issues in the pathologic assessment of NETs that are common among primaries of different sites. The various systems of nomenclature are compared along with new proposal for grading and staging NETs. Although differences persist, there are many common themes, such as the distinction of well-differentiated (low and intermediate-grade) from poorly differentiated (high-grade) NETs and the significance of proliferative rate in prognostic assessment. A recently published minimum pathology data set is presented to help standardize the information in pathology reports. Although an ultimate goal of standardizing the pathologic classification of all NETs, irrespective of primary site, remains elusive, an understanding of the common themes among the different current systems will permit easier translation of information relevant to prognosis and treatment.

NANETS treatment guidelines: well-differentiated neuroendocrine tumors of the stomach and pancreas

Well-differentiated neuroendocrine tumors (NETs) of the stomach and pancreas represent 2 major subtypes of gastrointestinal NETs. Historically, there has been little consensus on the classification and management of patients with these tumor subtypes. We provide an overview of well-differentiated NETs of the stomach and pancreas and describe consensus guidelines for the treatment of patients with these malignancies.