Well-differentiated neuroendocrine neoplasia: relapse-free survival and predictors of recurrence after curative intended resections

Molecular and Functional Heterogeneity of Primary Pancreatic Neuroendocrine Tumors and Metastases

INTRODUCTION

Treatment response to the standard therapy is low for metastatic pancreatic neuroendocrine tumors (PanNETs) mainly due to the tumor heterogeneity. We investigated the heterogeneity between primary PanNETs and metastases to improve the precise treatment.

METHODS

The genomic and transcriptomic data of PanNETs were retrieved from the Genomics, Evidence, Neoplasia, Information, Exchange (GENIE), and Gene Expression Omnibus (GEO) database, respectively. Potential prognostic effects of gene mutations enriched in metastases were investigated. Gene set enrichment analysis was performed to investigate the functional difference. Oncology Knowledge Base was interrogated for identifying the targetable gene alterations.

RESULTS

Twenty-one genes had significantly higher mutation rates in metastases which included TP53 (10.3% vs. 16.9%, p = 0.035) and KRAS (3.7% vs. 9.1%, p = 0.016). Signaling pathways related to cell proliferation and metabolism were enriched in metastases, whereas epithelial-mesenchymal transition (EMT) and TGF-β signaling were enriched in primaries. Gene mutations were highly enriched in metastases that had significant unfavorable prognostic effects included mutation of TP53 (p < 0.001), KRAS (p = 0.001), ATM (p = 0.032), KMT2D (p = 0.001), RB1 (p < 0.001), and FAT1 (p < 0.001). Targetable alterations enriched in metastases included mutation of TSC2 (15.5%), ARID1A (9.7%), KRAS (9.1%), PTEN (8.7%), ATM (6.4%), amplification of EGFR (6.0%), MET (5.5%), CDK4 (5.5%), MDM2 (5.0%), and deletion of SMARCB1 (5.0%).

CONCLUSION

Metastases exhibited a certain extent of genomic and transcriptomic diversity from primary PanNETs. TP53 and KRAS mutation in primary samples might associate with metastasis and contribute to a poorer prognosis. A high fraction of novel targetable alterations enriched in metastases deserves to be validated in advanced PanNETs.

Liver metastases of a neuroendocrine tumor arising from a tailgut cyst treated with interventional locoregional therapies: a case report and review of the literature on recurrent cases

A tailgut cyst is a rare, developmental cyst occurring in the presacral space. Although primarily benign, malignant transformation is a possible complication. Herein, we report a case of liver metastases after resection of a neuroendocrine tumor (NET) arising from a tailgut cyst. A 53-year-old woman underwent surgery for a presacral cystic lesion with nodules in the cyst wall. The tumor was diagnosed as a Grade 2 NET arising from a tailgut cyst. Thirty-eight months after surgery, multiple liver metastases were identified. The liver metastases were controlled with transcatheter arterial embolization and ablation therapy. The patient has survived for 51 months after the recurrence. Several NETs derived from tailgut cysts have been previously reported. According to our literature review, the proportion of Grade 2 tumors in NETs derived from tailgut cysts was 38.5%, and four of the 5 cases of Grade 2 NETs (80%) relapsed, while all eight cases of Grade 1 NETs did not relapse. Grade 2 NET may be a high-risk group for recurrence in NETs arising from tailgut cysts. The percentage of Grade 2 NETs in tailgut cysts was higher than that of rectal NETs, but lower than that of midgut NETs. To the best of our knowledge, this is the first case of liver metastases of a neuroendocrine tumor arising from a tailgut cyst that was treated with interventional locoregional therapies, and the first report to describe about the degree of malignancy of neuroendocrine tumors originating from tailgut cysts in terms of the percentage of Grade 2 NETs.

Evaluation of Pathologic Prognostic Factors in Neuroendocrine Tumors of the Small Intestine

The precise contributions of histopathologic features in the determination of stage and prognosis in small intestinal neuroendocrine tumors (NETs) are still under debate, particularly as they pertain to primary tumor size, mesenteric tumor deposits (TDs), and number of regional lymph nodes with metastatic disease. This single-institution series reviewed 162 patients with small bowel NETs (84 females, mean age: 60.3±12.0 y). All cases examined (100%) were immunoreactive for both chromogranin A and synaptophysin. Primary tumor size >1 cm (P=0.048; odds ratio [OR]=3.06, 95% confidence interval [CI]: 1.01-9.24) and lymphovascular invasion (P=0.007; OR=4.85, 95% CI: 1.53-15.40) were associated with the presence of lymph node metastasis. Conversely, TDs (P=0.041; OR=2.73, 95% CI: 1.04-7.17) and higher pT stage (P=0.006; OR=4.33, 95% CI: 1.53-12.28) were associated with the presence of distant metastasis (pM). A cutoff of ≥7 positive lymph nodes was associated with pM (P=0.041), and a thusly defined modified pN stage (pNmod) significantly predicted pM (P=0.024), compared with the prototypical pN (cutoff of ≥12 positive lymph nodes), which did not. Over a median follow-up of 35.7 months, higher pNmod (P=0.014; OR=2.15, 95% CI: 1.16-3.96) and pM (P<0.001; OR=11.00, 95% CI: 4.14-29.20) were associated with disease progression. Proportional hazards regression showed that higher pNmod (P=0.020; hazard ratio=1.51, 95% CI: 1.07-2.15) and pM (P<0.001; hazard ratio=5.48, 95% CI: 2.90-10.37) were associated with worse progression-free survival. Finally, Kaplan-Meier survival analysis demonstrated that higher pNmod (P=0.003), pM (P<0.001), and overall stage group (P<0.001) were associated with worse progression-free survival, while higher pM also predicted worse disease-specific survival (P=0.025). These data support requiring either chromogranin or synaptophysin, but not both, for small bowel NET diagnosis, the current inclusion of a 1 cm cutoff in primary tumor size and the presence of TDs in staging guidelines, and would further suggest lowering the cutoff number of positive lymph nodes qualifying for pN2 to 7 (from 12).

Relevant prognostic factors in patients with stage IV small intestine neuroendocrine neoplasms

There are few, but controversial data on the prognostic role of upfront primary tumour resection and mesenteric lymph node dissection (PTR) in patients with diffuse metastatic small intestinal neuroendocrine neoplasia (SI-NEN). Therefore, the prognostic role of PTR and other factors was determined in this setting. This retrospective cohort study included patients with stage IV SI-NETs with unresectable distant metastases without clinical and radiological signs of acute bowel obstruction or ischaemia. Patients diagnosed from January 2002 to May 2020 were retrieved from a prospective SI-NEN database. Disease specific overall survival (OS) was analysed with regard to upfront PTR and a variety of other clinical (e.g., gender, age, Hedinger disease, carcinoid syndrome, diarrhoea, laboratory parameters, metastatic liver burden, extrahepatic and extra-abdominal metastasis) and pathological (e.g., grading, mesenteric gathering) parameters by uni- and multivariate analysis. A total of 138 patients (60 females, 43.5%) with a median age of 60 years, of whom 101 (73%) underwent PTR and 37 (27%) did not, were included in the analysis. Median OS was 106 (95% CI: 72.52-139.48) months in the PTR group and 52 (95% CI: 30.55-73.46) in the non-PTR group (p = 0.024), but the non-PTR group had more advanced metastatic disease (metastatic liver burden ≥50% 32.4% vs. 13.9%). There was no significant difference between groups regarding the rate of surgery for bowel complications during a median follow-up of 51 months (PTR group 10.9% and non-PTR group 16.2%, p = 0.403). Multivariate analysis revealed age < 60 years, normal C-reactive protein (CRP) at baseline, absence of diarrhoea, less than 50% of metastatic liver burden, and treatment with PRRT as independent positive prognostic factors, whereas PTR showed a strong tendency towards better OS, but level of significance was missed (p = 0.067). However, patients who underwent both, PTR and peptide radioreceptor therapy (PRRT) had the best survival compared to the rest (137 vs. 73 months, p = 0.013). PTR in combination with PRRT significantly prolongs survival in patients with stage IV SI-NEN. Prophylactic PTR does also not result in a lower reoperation rate compared to the non-PTR approach regarding bowel complications.

Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?

Gastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN.

Management of Small Bowel Neuroendocrine Tumors

Small bowel neuroendocrine tumors (SBNETS) are slow-growing neoplasms with a noted propensity toward metastasis and comparatively favorable prognosis. The presentation of SBNETs is varied, although abdominal pain and obstructive symptoms are the most common presenting symptoms. In patients with metastases, hypersecretion of serotonin and other bioactive amines results in diarrhea, flushing, valvular heart disease, and bronchospasm, termed carcinoid syndrome. The treatment of SBNETs is multimodal and includes surgery, liver-directed therapy, somatostatin analogues, targeted therapy, and peptide receptor radionuclide therapy.

Predicting the recurrence risk of pancreatic neuroendocrine neoplasms after radical resection using deep learning radiomics with preoperative computed tomography images

Background

To establish and validate a prediction model for pancreatic neuroendocrine neoplasms (pNENs) recurrence after radical surgery with preoperative computed tomography (CT) images.

Methods

We retrospectively collected data from 74 patients with pathologically confirmed pNENs (internal group: 56 patients, Hospital I; external validation group: 18 patients, Hospital II). Using the internal group, models were trained with CT findings evaluated by radiologists, radiomics, and deep learning radiomics (DLR) to predict 5-year pNEN recurrence. Radiomics and DLR models were established for arterial (A), venous (V), and arterial and venous (A&V) contrast phases. The model with the optimal performance was further combined with clinical information, and all patients were divided into high- and low-risk groups to analyze survival with the Kaplan-Meier method.

Results

In the internal group, the areas under the curves (AUCs) of DLR-A, DLR-V, and DLR-A&V models were 0.80, 0.58, and 0.72, respectively. The corresponding radiomics AUCs were 0.74, 0.68, and 0.70. The AUC of the CT findings model was 0.53. The DLR-A model represented the optimum; added clinical information improved the AUC from 0.80 to 0.83. In the validation group, the AUCs of DLR-A, DLR-V, and DLR-A&V models were 0.77, 0.48, and 0.64, respectively, and those of radiomics-A, radiomics-V, and radiomics-A&V models were 0.56, 0.52, and 0.56, respectively. The AUC of the CT findings model was 0.52. In the validation group, the comparison between the DLR-A and the random models showed a trend of significant difference (P=0.058). Recurrence-free survival differed significantly between high- and low-risk groups (P=0.003).

Conclusions

Using DLR, we successfully established a preoperative recurrence prediction model for pNEN patients after radical surgery. This allows a risk evaluation of pNEN recurrence, optimizing clinical decision-making.

Neuroendocrine neoplasms of the duodenum, ampullary region, jejunum and ileum

Neuroendocrine neoplasms of the small intestine are some of the most frequently occurring along the gastrointestinal tract, even though their incidence is extremely variable according to specific sites. Jejunal-ileal neuroendocrine neoplasms account for about 27% of gastrointestinal NETs making them the second most frequent NET type. The aim of this review is to classify all tumors following the WHO 2019 classification and to describe their pathologic differences and peculiarities.

Prognostic Factors in Curative Resected Locoregional Small Intestine Neuroendocrine Neoplasms

BACKGROUND

Small intestinal neuroendocrine neoplasms (SI-NEN) are rare, and only about 40% of patients are diagnosed without distant metastases. Aim of the study was to identify prognostic factors in patients with potentially curative resected locoregional SI-NEN.

METHODS

Patients with curative resected locoregional SI-NEN (ENETS stages I-III) were retrieved from a prospective data base. Demographic, surgical and pathological data of patients with and without disease recurrence were retrospectively analyzed using univariate and multivariate analysis.

RESULTS

In a 20-year period, 65 of 203 (32%) patients with SI-NEN were operated for stages I-III disease. Thirty-eight (58.5%) patients were men, and the median age at surgery was 59 (range 37-87) years. After median follow-up of 65 months, 14 patients experienced disease relapse median 28.5 (range 6-122) months after initial surgery, of which 2 died due to their disease. Multivariate analysis revealed age ≥ 60 years (HR = 6.41, 95% CI 1.38-29.67, p = 0.017), tumor size ≥ 2 cm (HR = 26.54, 95% CI 4.46-157.62, p < 0.001), lymph node ratio > 0.5 (HR 7.18, 95% CI 1.74-29.74, p = 0.007) and multifocal tumor growth (HR = 6.98, 95% CI 1.66-29.39, p = 0.008) as independent negative prognostic factors and right hemicolectomy compared to segmental small bowel resection (HR = 0.04, 95% CI 0.01-0.24, p < 0.001) as independent protector against recurrence.

CONCLUSION

Patients with locoregional SI-NEN with an age ≥ 60 years, tumor size ≥ 2 cm, lymph node ratio > 0.5 and multiple small bowel tumor foci have an increased risk for recurrence and might benefit from adjuvant treatment. In contrast, right hemicolectomy of ileal SI-NEN seems to reduce the risk of recurrence.

Diagnosis and prognostic significance of extramural venous invasion in neuroendocrine tumors of the small intestine

Extramural venous invasion (EMVI) is an established independent prognostic factor in colorectal carcinoma where it is linked to hematogenous spread (i.e., liver metastases), influencing the decision for adjuvant chemotherapy. However, its prognostic significance in small intestinal neuroendocrine tumors (NETs) has not been studied, nor is it routinely assessed or reported. We reviewed primary small bowel NETs (14 jejunum, 82 ileum, 8 not specified) from 104 patients (52 women; median age 60.5, range: 24-84). EMVI was identified in 58 cases (55.8%), including in 13 of 21 equivocal cases using an elastin stain. In univariate analysis, EMVI was associated with lymphovascular and perineural invasion, tumor stage, and lymph node and distant metastases, whereas in multivariate analysis, only distant metastases remained significant (p < 0.001). Liver metastases were present in 55 cases (52.9%) and were significantly associated in univariate analysis with lymphovascular and perineural invasion, tumor stage, lymph node metastases, and EMVI, whereas in multivariate analysis, only EMVI remained significant (p < 0.001; odds ratio (OR) = 59.42). Eight patients developed metachronous liver metastases during follow-up (mean 22.9 ± 22.0 months, range: 4.7-73.2) and all (100%) were positive for EMVI. In contrast, of 49 patients who never developed liver metastases over significantly longer follow-up (mean 71.0 ± 32.4 months, range: 6.6-150.4; p < 0.001), only 7 (14.3%) had EMVI (p < 0.001). In Kaplan-Meier analysis, 8 of 15 patients with EMVI (53.3%) developed metachronous liver metastases, compared with 0 of 42 patients without EMVI (p < 0.001). In contrast, nonhepatic distant metastases, seen in 26 (25.0%) patients, were not associated with EMVI in multivariate or Kaplan-Meier analyses. Our data demonstrate that EMVI is common in small bowel NETs and strongly correlates with development of liver metastases. Therefore, its evaluation is critical and should be assessed in combination with adjuvant techniques such as elastin staining, if necessary. Moreover, inclusion of EMVI in pathology reporting guidelines should be considered.

Nomogram predicting the risk of recurrence after curative-intent resection of primary non-metastatic gastrointestinal neuroendocrine tumors: An analysis of the U.S. Neuroendocrine Tumor Study Group

BACKGROUND

The risk of recurrence after resection of non-metastatic gastro-entero-pancreatic neuroendocrine tumors (GEP-NET) is poorly defined. We developed/validated a nomogram to predict risk of recurrence after curative-intent resection.

METHODS

A training set to develop the nomogram and test set for validation were identified. The predictive ability of the nomogram was assessed using c-indices.

RESULTS

Among 1477 patients, 673 (46%) were included in the training set and 804 (54%) in y the test set. On multivariable analysis, Ki-67, tumor size, nodal status, and invasion of adjacent organs were independent predictors of DFS. The risk of death increased by 8% for each percentage increase in the Ki-67 index (HR 1.08, 95% CI, 1.05-1.10; P < 0.001). GEP-NET invading adjacent organs had a HR of 1.65 (95% CI, 1.03-2.65; P = 0.038), similar to tumors ≥3 cm (HR 1.67, 95% CI, 1.11-2.51; P = 0.014). Patients with 1-3 positive nodes and patients with >3 positive nodes had a HR of 1.81 (95% CI, 1.12-2.87; P = 0.014) and 2.51 (95% CI, 1.50-4.24; P < 0.001), respectively. The nomogram demonstrated good ability to predict risk of recurrence (c-index: training set, 0.739; test set, 0.718).

CONCLUSION

The nomogram was able to predict the risk of recurrence and can be easily applied in the clinical setting.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Midgut Neuroendocrine Tumors

There have been significant developments in diagnostic and therapeutic options for patients with neuroendocrine tumors (NETs). Key phase 3 studies include the CLARINET trial, which evaluated lanreotide in patients with nonfunctioning enteropancreatic NETs; the RADIANT-2 and RADIANT-4 studies, which evaluated everolimus in functioning and nonfunctioning NETs of the gastrointestinal tract and lungs; the TELESTAR study, which evaluated telotristat ethyl in patients with refractory carcinoid syndrome; and the NETTER-1 trial, which evaluated Lu-DOTATATE in NETs of the small intestine and proximal colon (midgut). Based on these and other advances, the North American Neuroendocrine Tumor Society convened a multidisciplinary panel of experts with the goal of updating consensus-based guidelines for evaluation and treatment of midgut NETs. The medical aspects of these guidelines (focusing on systemic treatment, nonsurgical liver-directed therapy, and postoperative surveillance) are summarized in this article. Surgical guidelines are described in a companion article.

Prognostic factors for disease relapse in patients with neuroendocrine tumours who underwent curative surgery

AIM

Surgery is the only modality of cure in patients diagnosed with neuroendocrine tumours (NETs). The aim of this study was to identify prognostic factors associated with disease relapse in patients with NETs treated by potentially-curative surgery.

METHODS

Sequential patients registered in The Christie European NET Society (ENETS) Centre of Excellence, with grade (G)1 or G2 NETs who had undergone curative surgery (February 2002-June 2014) were included. Investigated prognostic factors for relapse were: age, gender, TNM stage, tumour-localisation, functionality, genetic predisposition, presence of multiple NETs, second malignancy, grade (Ki-67-based), presence of vascular and/or perineural invasion, necrosis, surgical margin (R0/R1), Eastern Cooperative Oncology Group performance status and Adult Comorbidity Evaluation co-morbidity score.

RESULTS

One hundred and eighty-eight patients were identified [median age of 60 years (range 16-89)]. With a median follow-up of 2.6 years, 43 relapses occurred. The estimated median relapse-free survival (RFS) for the entire cohort was 8.0 years (95% confidence interval [CI] 5.9-10.0 years). In univariate analysis, primary NET location (p = 0.01), ENETS T-(HR-1.4; 95%-CI 1.0-2.0, p = 0.026), N-(HR-2.0, 95%-CI 1.1-3.9, p = 0.026) and M-stage (HR-2.6, 95%-CI 1.1-6.3, p = 0.052), grade (Ki-67%-based) (HR-2.5; 95%-CI 1.4-4.7; p = 0.003) and perineural invasion (HR-2.1; 95%-CI 1.1-3.9; p = 0.029) were prognostic for relapse. Factors remaining significant after multivariable analysis were tumour size (HR-1.67; 95%-CI 1.04-2.70; p = 0.03), nodal involvement (HR-2.61; 95%-CI 1.17-5.83; p = 0.013) and Ki-67 at the time of diagnosis (HR-1.93; 95%-CI 1.24-3.0; p = 0.002).

CONCLUSION

Size of tumour, lymph node involvement and Ki-67 were independent prognostic factors for relapse after potentially curative surgery in NET.