Sporadic Gastric Well-Differentiated Neuroendocrine Tumors Have a Higher Ki-67 Proliferative Index

Type 2 and type 3 gastric neuroendocrine tumors have high risk of lymph node metastasis: Systematic review and meta-analysis

OBJECTIVES

Lymph node metastasis (LNM) is crucial in determining treatment strategies for gastric neuroendocrine tumors (gNETs). While type 3 is considered more aggressive than types 1 and 2 within the clinical subtype of gNETs, the supporting data were insufficient, due to their rarity. We aimed to study the prevalence and risk factors associated with LNM in gNETs.

METHODS

We searched electronic databases from 1990 to 2023 to identify case-control and cohort studies regarding gNETs resected either endoscopically or surgically. The primary outcome measured was the pooled prevalence of LNM in gNETs. Secondary outcomes included categorizing the prevalence of LNM by clinical subtypes and identifying pathological risk factors associated with LNM in gNETs.

RESULTS

We included 28 studies, involving 1742 patients, among whom 240 had LNM (pooled prevalence rate, 11.8%; 95% confidence interval 7.6-17.9%). The pooled prevalence rates of LNM for type 1, type 2, and type 3 gNETs were 6.0%, 38.5%, and 23.2%, respectively. Type 2 (odds ratio [95% confidence interval] 11.53 [3.46-38.49]) and type 3 (6.88 [3.79-12.49]) gNETs exhibited a higher risk for LNM compared to type 1. Pathological risk factors for LNM included tumor size >10 mm (4.18 [1.91-9.17]), tumor invasion into the muscularis propria or deeper (11.21 [3.50-35.92]), grade 2/grade 3 (5.96 [2.65-13.40]), and lymphovascular invasion (34.50 [6.70-177.51]).

CONCLUSION

We demonstrated that type 2 gNETs, as well as type 3, had a high risk of LNM. Additionally, four pathological risk factors associated with LNM were identified.

Gastric Neuroendocrine Tumors (g-NETs): A Systematic Review of the Management and Outcomes of Type 3 g-NETs

PURPOSE

to collect data from real-life experiences of the management of type 3 g-NETs and identify possible prognostic factors that may impact the decision-making process.

METHODS

We performed a systematic review of the literature on type 3 g-NET management using the PubMed, MEDLINE, and Embase databases. We included cohort studies, case series, and case reports written in the English language.

RESULTS

We selected 31 out of 556 articles from between 2001 and 2022. In 2 out of the 31 studies, a 10 mm and 20 mm cut-off size were respectively associated with a higher risk of gastric wall infiltration and/or lymph node and distant metastasis at diagnosis. The selected studies reported a higher risk of lymph node or distant metastasis at diagnosis in the case of muscularis propria infiltration or beyond, irrespective of the dimensions or grading. From these findings, size, grading, and gastric wall infiltration seem to be the most relevant factors in management staff making choices and prognoses of type 3 g-NET patients. We produced a hypothetical flowchart for a standardized approach to these rare diseases.

CONCLUSION

Further prospective analyses are needed to validate the prognostic impact of the use of size, grading, and gastric wall infiltration as prognostic factors in the management of type 3 g-NETs.

Pathogenic ATM Variant-Harbouring Well-Differentiated Aggressive Type 1 Gastric Neuroendocrine Tumour with High-grade Features (G3 NET): a New Addition to the Clinical and Pathological Spectrum of Gastric Neuroendocrine Neoplasms

Gastric type 1 neuroendocrine tumours are considered to have low rates of proliferation and a good prognosis. We report here a patient with an aggressive well-differentiated high-grade gastric neuroendocrine tumour (gastric grade 3 NET), in a context of autoimmune gastritis. Consistent with grade 3 disease, the tumour had a Ki-67 proliferation index of 30%. Targeted next-generation sequencing identified variants of four genes, including a pathogenic ATM variant underlying the differentiation and metastatic potential of the tumour. Liver metastasis was diagnosed during follow-up, and the patient died after 6 years, due to disease progression.

An analysis of 130 neuroendocrine tumors G3 regarding prevalence, origin, metastasis, and diagnostic features

Limited data exist on high-grade neuroendocrine tumors (NETs G3) which represent a new category among neuroendocrine neoplasms (NEN). We analyzed NETs G3 in a consultation series regarding prevalence, origin, metastasis, and diagnostic problems. Based on the WHO classification of digestive system tumors, 130 NETs G3 (9%) were identified in 1513 NENs. NET G3 samples were more often obtained from metastatic sites (69%) than NET G1/G2 samples (24%). NET G3 metastases presented most frequently in the liver (74%) and originated from the pancreas (38/90, 42%), followed by the lung (9%), ileum (7%), stomach (3%), rectum (1%), and rare sites (2%) such as the prostate and breast. The primaries remained unknown in 15%. NETs G3 had a median Ki67 of 30% that distinguished them from NECs (60%), though with great overlap. The expression of site-specific markers, p53, Rb1, and SST2 was similar in NETs G3 and NETs G1/G2, except for p53 and Rb1 which were abnormally expressed in 8% and 7% of liver metastases from NET G3 but not from NET G1/G2. NETs G3 were frequently referred as NECs (39%) but could be well distinguished from NECs by normal p53 (92% versus 21%) and Rb1 expression (93% versus 41%) expression. In conclusion, NETs G3 are frequently discovered as liver metastases from pancreatic or pulmonary primaries and are often misinterpreted as NEC. p53 and Rb1 are powerful markers in the distinction of NET G3 from NEC. Rarely, carcinomas from non-digestive, non-pulmonary organs with neuroendocrine features may present as NET G3.

Risk factors for lymph node metastasis in gastric neuroendocrine tumor: a retrospective study

Background

Lymph node metastasis (LNM) plays a vital role in the determination of clinical outcomes in patients with gastric neuroendocrine tumor (G-NET). Preoperative identification of LNM is helpful for intraoperative lymphadenectomy. This study aims to investigate risk factors for LNM in patients with G-NET.

Methods

We performed a retrospective study involving 37 patients in non-LNM group and 82 patients in LNM group. Data of demographics, preoperative lab results, clinical–pathological results, surgical management, and postoperative situation were compared between groups. Significant parameters were subsequently entered into logistic regression for further analysis.

Results

Patients in LNM group exhibited older age (p = 0.011), lower preoperative albumin (ALB) (p = 0.003), higher carcinoembryonic antigen (CEA) (p = 0.020), higher International normalized ratio (p = 0.034), longer thrombin time (p = 0.018), different tumor location (p = 0.005), higher chromogranin A positive rate (p = 0.045), and higher Ki-67 expression level (p = 0.002). Logistic regression revealed ALB (p = 0.043), CEA (p = 0.032), tumor location (p = 0.013) and Ki-67 (p = 0.041) were independent risk factors for LNM in G-NET patients.

Conclusions

ALB, CEA, tumor location, and Ki-67 expression level correlate with the risk of LNM in patients with G-NET.

Genomics of High-Grade Neuroendocrine Neoplasms: Well-Differentiated Neuroendocrine Tumor with High-Grade Features (G3 NET) and Neuroendocrine Carcinomas (NEC) of Various Anatomic Sites

High-grade neuroendocrine neoplasms (HG-NENs) are clinically aggressive diseases, the classification of which has recently been redefined. They now include both poorly differentiated NENs (neuroendocrine carcinoma, NECs) and high proliferating well-differentiated NENs (called grade 3 neuroendocrine tumors, G3 NETs, in the digestive system). In the last decade, the "molecular revolution" that has affected all fields of medical oncology has also shed light in the understanding of HG NENs heterogeneity and has provided new diagnostic and therapeutic tools, useful in the management of these malignancies. Considering the kaleidoscopic aspects of HG NENs in various anatomical sites, this review systematically addresses the genomic landscape of such neoplasm throughout the more common thoracic and digestive locations, as well as it will consider other rare but not exceptional primary sites, including the skin, the head and neck, and the urogenital system. The revision of the available literature will then be oriented to understand the translational relevance of molecular data, by analyzing conceptual issues, clinicopathological correlations, and unmet needs in this field.

Clinicopathological characteristics and prognosis of 77 cases with type 3 gastric neuroendocrine tumours

BACKGROUND

For the rarity of type 3 gastric neuroendocrine tumours (g-NETs), their clinicopathological characteristics and prognosis are not well illustrated.

AIM

To describe the clinicopathological features and outcome of type 3 g-NETs in the Chinese population.

METHODS

Based on the 2019 WHO pathological classification, the clinicopathological characteristics and prognosis of patients with type 3 g-NETs in China were retrospectively analysed.

RESULTS

A total of 77 patients (55.8% of females) with type 3 g-NETs were analysed, with a median age of 48 years (range: 28-79 years). The tumours were mainly located in the gastric fundus/body (83.1%) and were mostly solitary (83.1%), with a median size of 1.5 cm (0.8-3.5 cm). Of these, there were 37 G1 tumours (48.1%), 31 G2 (40.3%), and 9 G3 (11.7%). Ten (13.0%) and 24 (31.2%) patients had lymph node and distant metastasis, respectively. In addition, type 3 g-NETs were heterogeneous. Compared with G1 NETs, G2 NETs had a higher lymph node metastasis rate, and G3 NETs had a higher distant metastasis rate. G1 and G2 NETs with stage I/II disease (33/68) received endoscopic treatment, and no tumour recurrence or tumour-related death was observed within a median follow-up time of 36 mo. Grade and distant metastasis were identified to be independent risk factors for prognosis in multivariable analysis.

CONCLUSION

Type 3 g-NETs are obviously heterogeneous, and the updated WHO 2019 pathological classification may be used to effectively evaluate their biological behaviors and prognosis. Also, endoscopic treatment should be considered for small (< 2 cm), low grade, superficial tumours.

Systematic review: management of localised low-grade upper gastrointestinal neuroendocrine tumours

BACKGROUND

Neuroendocrine tumours (NETs) of the stomach and duodenum are rare, but are increasing in incidence. Optimal management of localised, low-grade gastric and duodenal NETs remains controversial.

AIMS

To systematically review recent literature that has evaluated the management of localised low-grade gastric and duodenal NETs.

METHODS

A systematic literature search was conducted. Articles were screened and eligible articles fully assessed. Additional articles were identified through the included articles' reference lists.

RESULTS

Several relevant retrospective case series were identified, but there was considerable heterogeneity between studies and they reported a variety of parameters. Type I gastric NETs had an excellent prognosis and conservative management approaches such as endoscopic surveillance/resection were appropriate in most cases. Many type III gastric NETs were low grade and appeared to have a better prognosis than has previously been appreciated. Endoscopic rather than surgical resection was therefore effective in some patients who had small, low-grade tumours. Duodenal NETs were more heterogenous. Endoscopic resection was generally safe and effective in patients who had small, low-grade, nonfunctional, non-ampullary tumours. However, some patients, especially those with larger or ampullary duodenal NETs, required surgical resection.

CONCLUSIONS

Most type I gastric NETs behave indolently and surgical resection is only rarely indicated. Some type III gastric and duodenal NETs have a worse prognosis, but selected patients who have small, localised, nonfunctional, low-grade tumours are adequately and safely treated by endoscopic resection. Due to the complexity of this area, a multidisciplinary approach to management is strongly recommended.

Recurrence and metastatic potential in Type 1 gastric neuroendocrine neoplasms

BACKGROUND

The aim of our study was to assess clinico-pathological and biochemical parameters of Type 1 Gastric Neuroendocrine Neoplasms (GNEN1) with respect to tumours propensity for recurrence and metastasis.

METHODS

Hospital charts of GNEN1 patients were reviewed at a single tertiary referral centre.

RESULTS

We included 114 consecutive patients (74 women; age at baseline 54.5 ± 12.7 years [mean ± SD]) with GNEN1. All tumours (n = 114) were well differentiated; Grade 1 (G1) accounted for 56 patients (49%), whereas 46 (40%) were Grade 2 (G2) and 12 (11%) of unknown Grade. Overall follow-up encompassed 45.3 ± 46 (mean ± SD) months in 84 patients who were subjected to annual surveillance; 44 (52%) developed recurrence in the stomach during follow-up with 22 experiencing multiple recurrences; three (2.6%) presented with metastases in locoregional lymph nodes (n = 3) and/or the liver (n = 2); No metastasis or death was reported during follow-up. Median recurrence-free survival (RFS) was 31 months (95% CI: 7.6-54.4). Among clinico-pathological and biochemical parameters investigated, endoscopic intervention compared with surgery (P-value = .009) and higher serum-gastrin levels (s-gastrin) at baseline and first-year follow-up were associated with recurrence (P-value = .022 and .003 respectively) and also shorter RFS (log-rank P = .009 for type of intervention and .014 for s-gastrin, respectively). Receiver Operator Curve analysis of s-gastrin levels at first-year follow-up for recurrence demonstrated an area under the curve of 0.702.

CONCLUSION

Despite the relatively high prevalence of G2 tumours, endoscopically and/or surgically treated GNEN1 remains an indolent disease with a low metastatic propensity and no disease-specific mortality reported in our series. Many patients though will experience local recurrence, warranting long-term endoscopic surveillance with s-gastrin biomarker being a complementary tool in recurrence prediction.

Gastric neuroendocrine neoplasms type 1: A systematic review and meta-analysis

BACKGROUND

To date, the histopathological parameters predicting the risk of lymph node (LN) metastases and local recurrence, associated mortality and appropriateness of endoscopic or surgical resection in patients with gastric neuroendocrine neoplasms type 1 (GNENs1) have not been fully elucidated.

AIM

To determine the rate of LN metastases and its impact in survival in patients with GNEN1 in relation to certain clinico-pathological parameters.

METHODS

The PubMed, EMBASE, Cochrane Library, Web of Science and Scopus databases were searched through January 2019. The quality of the included studies and risk of bias were assessed using the Newcastle-Ottawa Scale (NOS) in accordance with the Cochrane guidelines. A random effects model and pooled odds ratios (OR) with 95%CI were applied for the quantitative meta-analysis.

RESULTS

We screened 2933 articles. Thirteen studies with 769 unique patients with GNEN1 were included. Overall, the rate of metastasis to locoregional LNs was 3.3% (25/769). The rate of LN metastases with a cut-off size of 10 mm was 15.3% for lesions > 10 mm (vs 0.8% for lesions < 10 mm) with a random-effects OR of 10.5 (95%CI: 1.4 -80.8; heterogeneity: P = 0.126; I 2 = 47.5%). Invasion of the muscularis propria was identified as a predictor for LN metastases (OR: 17.2; 95%CI: 1.8-161.1; heterogeneity: P = 0.165; I 2 = 44.5%), whereas grade was not clearly associated with LN metastases (OR: 2; 95%CI: 0.3-11.6; heterogeneity: P = 0.304; I 2 = 17.4%). With regard to GNEN1 local recurrence, scarce data were available. The 5-year disease-specific survival for patients with and without LN metastases was 100% in most available studies irrespective of the type of intervention. Surgical resection was linked to a lower risk of recurrence (OR: 0.3; 95%CI: 0.1-1.1; heterogeneity: P = 0.173; I 2 = 31.9%). The reported complication rates of endoscopic and surgical intervention were 0.6 and 3.8%, respectively.

CONCLUSION

This meta-analysis confirms that tumor size ≥ 10 mm and invasion of the muscularis propria are linked to a higher risk of LN metastases in patients with GNEN1. Overall, the metastatic propensity of GNEN1 is low with favorable 5-year disease-specific survival rates reported; hence, no clear evidence of the prognostic value of LN positivity is available. Additionally, there is a lack of evidence supporting the prediction of local recurrence in GNEN1, even if surgery was more often a definitive treatment.

A Case of Gastric Neuroendocrine Neoplasm with Mixed Grade: a Distinct Type of "High"-grade Well-Differentiated Neuroendocrine Neoplasm

Grade 3 neuroendocrine tumor (NET G3) is a rare new entity that has recently been introduced in the classification of neuroendocrine neoplasms of the pancreas. It is a well-differentiated form, with a high proliferative activity (Ki67 > 20%), and it represents a category whose prognosis is intermediate between NET G2 and poorly differentiated neuroendocrine carcinoma (NEC G3). In sites other than the pancreas, this new category is by far less coded. Herein is reported a case of NET G3 of the stomach, the 13th described in literature. The patient was a 71-year-old man with a mass in the gastric fundus. Histological examination revealed a neuroendocrine tumor that was mostly composed by areas with conventional well-differentiated features and intermediate proliferative rate (< 20 mitoses/10 HPFs and 7% Ki67); part of the tumor was characterized by increased nuclear atypia, a confluent growth pattern, intermediate mitotic activity, and high Ki67 value (25%). The tumor was studied immunohistochemically and molecularly, and the only alteration that came out was MEN1 gene mutation (Lau584SerfsTer5) in both the high- and low-grade components. According to the actual classification of gastric neuroendocrine neoplasms, this case is labeled as NEC G3 but it should be named NET G3, with a much better prognosis than the former. Overall, both morphological pattern and the Ki67 value should be mentioned in the histological report in cases of high-grade neuroendocrine neoplasms because of its clinical significance in defining the prognosis and for new potential therapeutic approaches.

Prognostic Evaluations Tailored to Specific Gastric Neuroendocrine Neoplasms: Analysis Of 200 Cases with Extended Follow-Up

BACKGROUND

Gastric neuroendocrine neoplasms (NENs) are very heterogeneous, ranging from mostly indolent, atrophic gastritis-associated, type I neuroendocrine tumors (NETs), through highly malignant, poorly differentiated neuroendocrine carcinomas (pdNECs), to sporadic type III NETs with intermediate prognosis, and various rare tumor types. Histologic differentiation, proliferative grade, size, level of gastric wall invasion, and local or distant metastases are used as prognostic markers. However, their value remains to be tailored to specific gastric NENs.

METHODS

Series of type I NETs (n = 123 cases), type III NETs (n = 34 cases), and pdNECs (n = 43 cases) were retrospectively collected from four pathology centers specializing in endocrine pathology. All cases were characterized clinically and histopathologically. During follow-up (median 93 months) data were recorded to assess disease-specific patient survival.

RESULTS

Type I NETs, type III NETs, and pdNECs differed markedly in terms of tumor size, grade, invasive and metastatic power, as well as patient outcome. Size was used to stratify type I NETs into subgroups with significantly different invasive and metastatic behavior. All 70 type I NETs < 0.5 cm (micro-NETs) were uneventful. Ki67-based grading proved efficient for the prognostic stratification of type III NETs; however, grade 2 (G2) was not associated with tumor behavior in type I NETs. Although G3 NETs (2 type I and 9 type III) had a very poor prognosis, it was found that patient survival was longer with type III G3 NETs compared to pdNECs.

CONCLUSIONS

Given the marked, tumor type-related behavior differences, evaluation of gastric NEN prognostic parameters should be tailored to the type of neoplastic disease.