Commonwealth Neuroendocrine Tumour Research Collaboration and the North American Neuroendocrine Tumor Society Guidelines for the Diagnosis and Management of Patients With Lung Neuroendocrine Tumors: An International Collaborative Endorsement and Update of the 2015 European Neuroendocrine Tumor Society Expert Consensus Guidelines

Clinical management of typical and atypical carcinoids/neuroendocrine tumors in ENETS centres of excellence (CoE): Survey from the ENETS lung NET task force

Lung carcinoid tumours are neuroendocrine neoplasms originating from the bronchopulmonary tract's neuroendocrine cells, accounting for only 1%-3% of all lung cancers but 30% of all neuroendocrine tumours. The incidence of lung carcinoids, both typical and atypical, has been increasing over the years due to improved diagnostic methods and increased awareness among clinicians and pathologists. The most recent WHO classification includes a subgroup of lung carcinoids with atypical morphology and higher mitotic count and/or Ki67 labelling index. Despite appropriate surgery, the 5-year survival rate for atypical carcinoids barely exceeds 50%-70%. The role of adjuvant therapy in lung carcinoids is not well-defined, and clinical decisions are generally based on the presence of high-risk features. Long-term follow-up is essential to monitor for recurrence, although the optimal follow-up protocol remains unclear. To address the lack of consensus in clinical management decisions, the European Neuroendocrine Tumor Society (ENETS) initiated a survey among 20 expert centres. The survey identified varied opinions on approaches to imaging, surgery, use of adjuvant therapy, and follow-up protocols. Notably, the absence of dedicated multidisciplinary lung neuroendocrine tumour boards in some centres was evident. Experts agreed on the need for a prospective adjuvant trial in high-risk patients, emphasizing the feasibility of such a study. In conclusion, the study highlights the need for a more uniform adoption of existing guidelines in the management of lung carcinoid tumours and emphasizes the importance of international collaboration to advance research and patient care. Close collaboration between healthcare providers and patients is vital for effective long-term surveillance and management of these rare tumours.

Segmentectomy and wedge resection are equivalent for the treatment of early-stage pulmonary carcinoid tumors: A retrospective cohort study

Currently, there is no consensus regarding the extent of surgery for stage I pulmonary carcinoid (PC) tumors, which encompass typical carcinoid (TC) and atypical carcinoid (AC) tumors. Sublobar resection includes segmental resection and wedge resection; the former is regarded as a type of anatomical resection that is better suited for tumor treatment. Therefore, it needs to be further verified whether differences exist in the effects of the two surgical methods on the survival time of patients. Propensity score matching (PSM) was used. The primary endpoints were cancer-specific survival (CSS) and overall survival (OS) time. Survival differences were analyzed via the Kaplan-Meier method and the log-rank test. There was no significant difference in survival between the sublobar resection and lobectomy groups after PSM in either the TC or AC tumor groups (all p > 0.05). A total of 1680 patients underwent pulmonary wedge resection (TC: n = 1547, AC: n = 133), and 398 patients underwent segmental resection (TC: n = 365, AC: n = 33). After PSM, there were no statistically significant differences in survival, regardless of whether OS or CSS was considered the primary endpoint (OS: p = 0.337; CSS: p = 0.470). Furthermore, segmental resection did not prolong patient survival time compared with wedge resection in different subgroup analyses on the basis of histology, age, and tumor size (all p > 0.05). Finally, the same results were obtained via multivariate Cox analysis (OS: p = 0.153; HR = 1.21; CSS: p = 0.351, HR = 1.32). Sublobar resection could be considered for patients with early-stage typical or atypical pulmonary carcinoid, provided that a rigorous lymph node evaluation is conducted. If the tumor is distant from the pulmonary hilum, either segmentectomy or wedge resection may be performed depending on the specific location of the tumor and the clinical condition of the patient.

Absence of orthopaedia homeobox protein (OTP) expression is associated with disease spread and adverse outcome in pulmonary carcinoid tumour patients

Pulmonary carcinoid (PC) tumours typically have a good prognosis, although metastases occur, and the disease may progress after a long period of time. Expression of orthopaedia homeobox protein (OTP) has been recognized as a possible independent prognostic marker in PCs. Immunohistochemical (IHC) OTP expression has been associated with better prognosis, but the staining has yet to be implemented in routine clinical diagnostics. In response to this, two new monoclonal OTP antibodies were recently developed.This retrospective study included 164 PC patients operated on at Helsinki University Hospital between 1990 and 2020. Tissue microarray slides, prepared from formalin-fixed and paraffin-embedded primary tumour samples, were stained with OTP IHC using one polyclonal and two novel monoclonal antibodies.Absence of OTP expression was associated with a shorter disease-specific survival (DSS) and disease progression (p < 0.001). Patients without OTP expression had a 5-year DSS of 73-79%, whereas 5-year DSS was 91-94% with OTP expression, depending on the primary antibody. In a univariable Cox regression model, absence of OTP expression was associated with adverse outcome along with atypical histological subtype, metastatic disease, Ki-67 proliferation index > 1%, and larger tumour size. In a multivariable Cox regression model, only absence of OTP expression and lymph node involvement at the time of diagnosis were associated with risk of worse prognosis. All three antibodies showed good concordance with each other.Our findings support the role of OTP as an independent prognostic marker in PCs and applicability of IHC staining in routine clinical use with novel monoclonal antibodies.

Assessment of the current and emerging criteria for the histopathological classification of lung neuroendocrine tumours in the lungNENomics project

BACKGROUND

Six thoracic pathologists reviewed 259 lung neuroendocrine tumours (LNETs) from the lungNENomics project, with 171 of them having associated survival data. This cohort presents a unique opportunity to assess the strengths and limitations of current World Health Organization (WHO) classification criteria and to evaluate the utility of emerging markers.

PATIENTS AND METHODS

Patients were diagnosed based on the 2021 WHO criteria, with atypical carcinoids (ACs) defined by the presence of focal necrosis and/or 2-10 mitoses per 2 mm2. We investigated two markers of tumour proliferation: the Ki-67 index and phospho-histone H3 (PHH3) protein expression, quantified by pathologists and automatically via deep learning. Additionally, an unsupervised deep learning algorithm was trained to uncover previously unnoticed morphological features with diagnostic value.

RESULTS

The accuracy in distinguishing typical from ACs is hampered by interobserver variability in mitotic counting and the limitations of morphological criteria in identifying aggressive cases. Our study reveals that different Ki-67 cut-offs can categorise LNETs similarly to current WHO criteria. Counting mitoses in PHH3+ areas does not improve diagnosis, while providing a similar prognostic value to the current criteria. With the advantage of being time efficient, automated assessment of these markers leads to similar conclusions. Lastly, state-of-the-art deep learning modelling does not uncover undisclosed morphological features with diagnostic value.

CONCLUSIONS

This study suggests that the mitotic criteria can be complemented by manual or automated assessment of Ki-67 or PHH3 protein expression, but these markers do not significantly improve the prognostic value of the current classification, as the AC group remains highly unspecific for aggressive cases. Therefore, we may have exhausted the potential of morphological features in classifying and prognosticating LNETs. Our study suggests that it might be time to shift the research focus towards investigating molecular markers that could contribute to a more clinically relevant morpho-molecular classification.

Mutational analysis of pulmonary large cell neuroendocrine carcinoma: APC gene mutations identify a good prognostic factor

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a highly aggressive neoplasm with biological heterogeneity. Mutations in multiple genes have been identified in LCNEC. However, associations between gene alterations, histopathological characteristics, and prognosis remain ambiguous. Here, we investigated the clinicopathologic, immunohistochemical, and genomic characteristics of 19 patients with LCNEC and 9 patients with atypical carcinoid (AC). We revealed high mutation frequencies of TP53 (89.5 %), RB1 (42.1 %), APC (31.6 %), and MCL1 (31.6 %) in LCNEC, while genetic alterations were rarely found in AC. APC alterations mainly occurred to the exon 16 and were only identified in LCNEC with wild-type RB1. The 19 LCNEC were further subgrouped into APC wild-type (LCNEC-APCMT, 6/19) and APC-mutated (LCNEC-APCWT, 13/19) subgroups. In comparison with LCNEC-APCWT, LCNEC-APCMT displayed lower TMB (median: 12.64 vs 4.20, P = 0.045), and relatively mild cytologic atypia. In addition, LCNEC-APCMT distinguished itself from AC and LCNEC-APCWT by obviously downregulated expression of neuroendocrine markers (CD56 and Syn, P < 0.01) and significantly altered expression of genes downstream of APC (β-catenin migrating into the cytoplasm and nucleus, P < 0.001; c-Myc upregulating, P = 0.005). The OS of LCNEC-APCMT was numerically intermediate between AC and LCNEC-APCWT. We first proposed that APC alterations were common in LCNEC with wild-type RB1 and that LCNEC-APCMT was associated with lower TMB and better OS in comparison with LCNEC-APCWT.

Metastatic Neuroendocrine Neoplasms to the Pancreas: Two Unusual Cases and a Review of the Literature

Neuroendocrine tumor metastases to the pancreas are rare, and they share substantial overlap with the significantly more common primary pancreatic neuroendocrine neoplasms, representing a potential diagnostic pitfall. Elucidating whether a neuroendocrine tumor within the pancreas is a primary neoplasm versus a metastasis has significant prognostic and treatment implications. Correlation with clinical history and imaging as well as incorporating an appropriate immunohistochemical panel are essential to establish the correct diagnosis. Herein, we present 2 rare neuroendocrine tumors that metastasized to the pancreas: a medullary thyroid carcinoma and an atypical carcinoid tumor of lung origin. We also provide a brief review of the literature.

Hepatic cytoreduction for lung and renal neuroendocrine tumor metastases

BACKGROUND

Patients with hepatic metastases from lung and renal neuroendocrine tumors are rare. Outcome data on treatment of hepatic metastases for these types of tumors are lacking. We report the outcomes of hepatic cytoreduction operations for these tumors.

METHODS

Records of patients undergoing hepatic cytoreduction operations of at least 70 ​% of the hepatic tumors for well differentiated lung and renal neuroendocrine tumors were reviewed. Data collected included primary tumor type, number and size of metastases resected, tumor grade, percentage of hepatic cytoreduction, presence of extra-hepatic disease, and status at last follow up.

RESULTS

Twenty-one patients were identified. Ninety percent had extrahepatic metastases. Median-time to liver progression was 66 months. The five-year survival rate was 65 ​%. Liver failure was the predominant cause of death. No prognostic factors for survival could be identified among the variables collected.

CONCLUSION

Hepatic cytoreduction operations for lung and renal neuroendocrine tumors do not yield as good of survival rates as observed with small bowel and pancreatic neuroendocrine tumors, but are considerably better than those obtained with complete resection of colorectal metastases.

Updates on lung neuroendocrine neoplasm classification

Lung neuroendocrine neoplasms (NENs) are a heterogeneous group of pulmonary neoplasms showing different morphological patterns and clinical and biological characteristics. The World Health Organisation (WHO) classification of lung NENs has been recently updated as part of the broader attempt to uniform the classification of NENs. This much-needed update has come at a time when insights from seminal molecular characterisation studies revolutionised our understanding of the biological and pathological architecture of lung NENs, paving the way for the development of novel diagnostic techniques, prognostic factors and therapeutic approaches. In this challenging and rapidly evolving landscape, the relevance of the 2021 WHO classification has been recently questioned, particularly in terms of its morphology-orientated approach and its prognostic implications. Here, we provide a state-of-the-art review on the contemporary understanding of pulmonary NEN morphology and the potential contribution of artificial intelligence, the advances in NEN molecular profiling with their impact on the classification system and, finally, the key current and upcoming prognostic factors.

Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension with bronchial obstruction by a carcinoid tumor

Pulmonary endarterectomy (PEA) is a standard treatment for chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH combined with bronchial obstruction by a tumor is rare but should be assessed carefully because PEA for obstructed segments can be less therapeutic and make the subsequent surgical resection challenging. This report describes a case of CTEPH with bronchial obstruction by a typical carcinoid tumor in a 75-year-old man. On-site evaluation and removal of the obstructive tumor were performed bronchoscopically, increasing the effectiveness of subsequent PEA for all affected pulmonary segments. This report illustrates a PEA strategy to treat CTEPH with bronchial tumor obstruction.

Lung Carcinoids: A Comprehensive Review for Clinicians

Lung carcinoids are neuroendocrine tumors, categorized as typical or atypical carcinoids based on their histological appearance. While most of these tumors are slow-growing neoplasms, they still possess malignant potential. Many patients are diagnosed incidentally on chest X-rays or CT scans. Presenting symptoms include cough, hemoptysis, wheezing, dyspnea, and recurrent pneumonia. Endocrine symptoms, such as carcinoid syndrome or ectopic Cushing's syndrome, are rare. Surgery is the primary treatment and should be considered in all patients with localized disease, even when thoracic lymph node metastases are present. Patients with distant metastases may be treated with somatostatin analogues, chemotherapy, preferably temozolomide-based, mTOR inhibitors, or peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE. Most patients have an excellent prognosis. Poor prognostic factors include atypical histology and lymph node metastases at diagnosis. Long-term follow-up is mandatory since metastases may occur late.

Defining MRI Superiority over CT for Colorectal and Neuroendocrine Liver Metastases

BACKGROUND

We compared CT and MRI for staging metastatic colorectal or neuroendocrine liver metastases (CRLMs and NELMs, respectively) to assess their impact on tumor burden.

METHODS

A prospectively maintained database was queried for patients who underwent both imaging modalities within 3 months, with two blinded radiologists (R1 and R2) independently assessing the images for liver lesions. To minimize recall bias, studies were grouped by modality, and were randomized and evaluated separately.

RESULTS

Our query yielded 76 patients (42 CRLMs; 34 NELMs) with low interrater variability (intraclass correlation coefficients: CT = 0.941, MRI = 0.975). For CRLMs, there were no significant differences in lesion number or size between CT and MRI. However, in NELMs, Eovist®-enhanced MRI detected more lesions (R1: 14.3 vs. 12.1, p = 0.02; R2: 14.4 vs. 12.4, p = 0.01) and smaller lesions (R1: 5.7 vs. 4.4, p = 0.03; R2: 4.8 vs. 2.9, p = 0.02) than CT.

CONCLUSIONS

CT and MRI are equivalent for CRLMs, but for NELMs, MRI outperforms CT in detecting more and smaller lesions, potentially influencing treatment planning and surgery.

Neuroendocrine neoplasms of the orbit: report of three cases and a literature review

Neuroendocrine neoplasms (NENs) originate from neuroendocrine cells, and mainly occur in the gastrointestinal tract and lungs, rarely occurring in the orbit. Here, the clinicopathologic factors, treatments and prognosis of three cases of orbital NENs are described. The mean age of the three patients (two females and one male) was 59 years. Two cases exhibited ocular symptoms, including unilateral proptosis and eyelid mass, while the third case presented systemic symptoms exhibited as Cushing's syndrome. The tumours were surgically resected in all three patients. Immunohistochemistry assays revealed positive expression for pan cytokeratin and epithelial membrane antigen in all cases. Additionally, neural cell adhesion molecule 1 (also known as CD56) and synaptophysin were positive in two cases. The pathological diagnosis for case 1 and 2 was 'neuroendocrine carcinoma' and both patients died three months after diagnosis. Case 3 was diagnosed with a neuroendocrine tumour and the symptoms of Cushing's syndrome gradually improved following surgery. In addition, no recurrence was observed during the four-year follow-up period. These cases demonstrate that orbital neuroendocrine tumours show different clinical manifestations due to the different types. Pathology may clarify the diagnosis, classification and grading, and provide a reference value for treatment and prognosis.

A Competing Risk Model Nomogram to Predict the Long-Term Prognosis of Lung Carcinoid

BACKGROUND

The prediction of long-term, cancer-specific survival of lung carcinoid remains controversial. We aimed to build a prognostic model by using competing-risk analysis to predict the long-term, cancer-specific survival of lung carcinoid patients.

METHODS

Patients were retrospectively enrolled from the SEER database, and clinicopathological data were collected. Univariable and multivariable competing-risk analyses were conducted to identify prognostic factors. A competing-risk model and a nomogram were developed by using independent prognostic factors. The model was assessed by using concordance index and calibration curves.

RESULTS

A total of 2496 patients were enrolled, of which 267 (10.7%) died of diagnosed carcinoma; 316 (12.7%) died because of other reasons. The 5-year, 10-year, and 15-year cancer-specific survival of carcinoid patients were 91.35%, 86.60%, and 84.39%, respectively. Multivariable analysis demonstrated that increasing age, male, larger tumor size, higher N stage, M1, atypical carcinoid, and undergoing no surgery were independent risk factors. A competing-risk model based on the risk factors and a corresponding nomogram were developed. Concordance index of the developed model for 5-year, 10-year, and 15-year were 0.891, 0.856, 0.836 respectively in the training cohort and 0.876, 0.841, 0.819 respectively in the validation cohort after bootstrap adjustment. The calibration curves of 5-year, 10-year, and 15-year showed good agreement.

CONCLUSIONS

Increasing age, male, larger tumor size, higher N stage, M1, atypical carcinoid, and undergoing no surgery were independent risk factors. A competing risk model of excellent performance in predicting long-term survival was developed, and a nomogram was established.

Role of Advanced Gastrointestinal Endoscopy in the Comprehensive Management of Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs), also called neuroendocrine tumors (NETs), are relatively uncommon, heterogenous tumors primarily originating in the gastrointestinal tract. With the improvement in technology and increasing use of cross-sectional imaging and endoscopy, they are being discovered with increasing frequency. Although traditionally considered indolent tumors with good prognoses, some NENs exhibit aggressive behavior. Timely diagnosis, risk stratification, and management can often be a challenge. In general, small NENs without local invasion or lymphovascular involvement can often be managed using minimally invasive advanced endoscopic techniques, while larger lesions and those with evidence of lymphovascular invasion require surgery, systemic therapy, or a combination thereof. Ideal management requires a comprehensive and accurate understanding of the stage and grade of the tumor. With the recent advancements, a therapeutic advanced endoscopist can play a pivotal role in diagnosing, staging, and managing this rare condition. High-definition white light imaging and digital image enhancing technologies like narrow band imaging (NBI) in the newer endoscopes have improved the diagnostic accuracy of traditional endoscopy. The refinement of endoscopic ultrasound (EUS) over the past decade has revolutionized the role of endoscopy in diagnosing and managing various pathologies, including NENs. In addition to EUS-directed diagnostic biopsies, it also offers the ability to precisely assess the depth of invasion and lymphovascular involvement and thus stage NENs accurately. EUS-directed locoregional ablative therapies are increasingly recognized as highly effective, minimally invasive treatment modalities for NENs, particularly pancreatic NENs. Advanced endoscopic resection techniques like endoscopic submucosal dissection (ESD), endoscopic submucosal resection (EMR), and endoscopic full-thickness resection (EFTR) have been increasingly used over the past decade with excellent results in achieving curative resection of various early-stage gastrointestinal luminal lesions including NENs. In this article, we aim to delineate NENs of the different segments of the gastrointestinal (GI) tract (esophagus, gastric, pancreatic, and small and large intestine) and their management with emphasis on the endoscopic management of these tumors.

Systemic treatment for neuroendocrine non-small cell lung carcinoma: A cases series and a systematic review of the literature

INTRODUCTION

Neuroendocrine lung cancer constitutes a continuum from carcinoid tumours (CT) to large cell neuroendocrine (LCNEC) and small-cell carcinomas (SCLC). Except for SCLC, there is no consensual agreement on systemic therapy. The aim of this study is to review our clinical experience among patients with CT and LCNEC in the light of a systematic review of the literature.

METHODS

A retrospective study of all patients with CT and LCNEC receiving a systemic therapy at Institut Jules Bordet and Erasme Hospital between 01/01/2000-31/12/2020. A systematic review of the literature was performed in Ovid Medline.

RESULTS

53 patients (21 CT and 32 LCNEC) were included. Despite limited response rates, patients with CT receiving a "carcinoid-like" 1st-line regimen (somatostatin analogues (SSA), everolimus, peptide receptor radionuclide therapy (PRRT)) had a numerically longer survival compared to those receiving other type of regimens (median 51.4 vs 18.6 months, respectively; p = 0.17). We observed a similar survival between 1st line "SCLC-like" vs "non-small cell lung cancer (NSCLC)-like" schemes in LCNEC (median 11.2 vs 12.6 months, respectively; p = 0.46). The systematic review identified 23 studies (12 prospective, 15 and 8 for CT and LCNEC respectively). For CT, everolimus and SSA led to prolonged disease control with an acceptable toxicity profile, while higher response rates but lower tolerance were associated with PRRT and chemotherapy regimens including oxaliplatine and dacarbazine. For LCNEC, no difference emerged when comparing "SCLC-like" and "NSCLC-like" regimens considering response rate, progression-free or overall survival.

CONCLUSIONS

SSA, everolimus and PRRT present a good therapeutic index for CT, while the role of chemotherapy remains limited to aggressive and rapidly evolving CT. The best type of chemotherapy regimen remains an open question in LCNEC.

Spotlight on Small-Cell Lung Cancer and Other Lung Neuroendocrine Neoplasms

Lung neuroendocrine neoplasms (NENs) encompass a spectrum of neoplasms that are subdivided into the well-differentiated neuroendocrine tumors comprising the low- and intermediate-grade typical and atypical carcinoids, respectively, and the poorly differentiated, high-grade neuroendocrine carcinomas including large-cell neuroendocrine carcinomas and small-cell lung carcinoma (SCLC). Here, we review the current morphological and molecular classifications of the NENs on the basis of the updated WHO Classification of Thoracic Tumors and discuss the emerging subclassifications on the basis of molecular profiling and the potential therapeutic implications. We focus on the efforts in subtyping SCLC, a particularly aggressive tumor with few treatment options, and the recent advances in therapy with the adoption of immune checkpoint inhibitors in the frontline setting for patients with extensive-stage SCLC. We further highlight the promising immunotherapy strategies in SCLC that are currently under investigation.

Neuroendocrine Neoplasms: Genetics and Epigenetics

Neuroendocrine neoplasms (NENs) are a group of rare, heterogeneous tumors of neuroendocrine cell origin, affecting a range of different organs. The clinical management of NENs poses significant challenges, as tumors are often diagnosed at an advanced stage where overall survival remains poor with current treatment regimens. In addition, a host of complex and often unique molecular changes underpin the pathobiology of each NEN subtype. Exploitation of the unique genetic and epigenetic signatures driving each NEN subtype provides an opportunity to enhance the diagnosis, treatment, and monitoring of NEN in an emerging era of individualized medicine.

The Surgical Management of Lung Neuroendocrine Neoplasms

This review summarizes key recent developments relevant to the surgical management of lung neuroendocrine neoplasms (L-NENs), including typical and atypical carcinoids, large cell neuroendocrine carcinoma, and small cell lung carcinoma. This review includes recent insights into the classification, clinical presentation, diagnostic workup, treatment options, and follow-up. Highlighted topics include general principles of surgery in localized or locally advanced or metastatic L-NENs, lung-sparing surgery for small, peripheral typical carcinoids, adjuvant and systemic therapies for typical and atypical carcinoids, and surgery and adjuvant therapies for large cell neuroendocrine carcinoma and small cell lung carcinoma.

A 46-Year-Old Woman With Chronic Dyspnea and Diarrhea

CASE PRESENTATION

A 46-year-old previously healthy woman presented with dyspnea, fatigue, and diarrhea. She had been experiencing these symptoms for > 1 year, but they had worsened in the few weeks prior to presentation. She had become progressively dyspneic on exertion and at rest and had increased the number of pillows she was sleeping on at night. She reported having episodes of nonbloody, watery diarrhea five to six times a day. The episodes were not associated with abdominal pain or recent travel and occurred even with fasting. Review of systems was positive for intermittent hot flashes, heart palpitations, and myalgias. She was premenopausal. She denied fever, weight loss, cough, hemoptysis, chest pain, or new edema. She had a pertinent medical history of gastritis, a nonspecific murmur since childhood, current tobacco use with a five pack-year history, and a family history of non-first-degree relatives having lung, breast, and colon cancer. She had not received medical care since moving from Brazil to the United States 4 years earlier.

Immune Checkpoint Inhibitor Therapy in Neuroendocrine Tumors

Neuroendocrine tumors (NETs) occur in various regions of the body and present with complex clinical and biochemical phenotypes. The molecular underpinnings that give rise to such varied manifestations have not been completely deciphered. The management of neuroendocrine tumors (NETs) involves surgery, locoregional therapy, and/or systemic therapy. Several forms of systemic therapy, including platinum-based chemotherapy, temozolomide/capecitabine, tyrosine kinase inhibitors, mTOR inhibitors, and peptide receptor radionuclide therapy have been extensively studied and implemented in the treatment of NETs. However, the potential of immune checkpoint inhibitor (ICI) therapy as an option in the management of NETs has only recently garnered attention. Till date, it is not clear whether ICI therapy holds any distinctive advantage in terms of efficacy or safety when compared to other available systemic therapies for NETs. Identifying the characteristics of NETs that would make them (better) respond to ICIs has been challenging. This review provides a summary of the current evidence on the value of ICI therapy in the management of ICIs and discusses the potential areas for future research.

A Rare Case of Neuroendocrine Tumor in a Patient With Neurofibromatosis Type 1: Is There Any Association?

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition characterized by café-au-lait spots, cutaneous neurofibromas, axillary and inguinal freckling, and iris Lisch nodules; however, the presentations vary greatly, even within families. NF1 is also a recognized risk factor for the development of malignancy particularly malignant peripheral nerve sheath tumors (MPNST), optic gliomas, other gliomas, and leukemia. Nevertheless, the occurrence of lung cancer in a patient with neurofibromatosis type 1 is a rare phenomenon.

Here we present a case of neuroendocrine tumor in a patient with neurofibromatosis type 1, highlighting the association between the two diseases. This case report also aimed to raise awareness of possible malignancies in patients with neurofibromatosis type 1.

Lymphadenectomy for lung carcinoids: Which factors may predict nodal upstaging? A multi centric, retrospective study

OBJECTIVE

To investigate risk factors for nodal upstaging in patients with lung carcinoids and to understand which type of lymphadenectomy is most appropriate.

METHODS

Data regarding patients with lung carcinoids, who underwent surgical resection and lymphadenectomy in five institutions from January 1, 2005 to December 31, 2019, were collected and retrospectively analyzed. Clinical and pathological tumor characteristics were correlated to analyze lymph node upstaging.

RESULTS

The analysis was conducted on 283 patients. Pathology showed 230 typical and 53 atypical carcinoids. Nodal and mediastinal upstaging occurred in 33 (11.6%) and 16 (5.6%) patients, respectively. At the univariable analysis, nodal upstaging was significantly correlated with central location (p = 0.003), atypical histology (p < 0.001), pT dimension (p = 0.004), and advanced age (p = 0.043). The multivariable analysis confirmed atypical histology (odds ratio [OR]: 11.030; 95% confidence interval [CI]: 4.837-25.153, p < 0.001) and central location (OR: 3.295; 95% CI: 1.440-7.540, p = 0.005) as independent prognostic factors for nodal upstaging. Atypical histology (p < 0.001), pT dimension (p = 0.036), number of harvested lymph node stations (p = 0.047), and type of lymphadenectomy (p < 0.001) correlated significantly with mediastinal upstaging. The multivariable analysis confirmed atypical histology (OR: 5.408; 95% CI: 1.391-21.020, p = 0.015) and pT (OR: 1.052; 95% CI: 1.021-1.084, p = 0.001) as independent prognostic factors.

CONCLUSION

Atypical histology, dimension, and central location are associated with a high-risk for occult hilo-mediastinal metastases, and mediastinal radical dissection may predict nodal upstaging. Thus, we suggest radical mediastinal lymph node dissection in high-risk tumors, reserving sampling, or lobe-specific dissection in peripheral, small typical carcinoids.

Diagnostic criteria and evolving molecular characterization of pulmonary neuroendocrine carcinomas

Neuroendocrine carcinomas of the lung are currently classified into two categories: small cell lung carcinoma and large cell neuroendocrine carcinoma. Diagnostic criteria for small cell- and large cell neuroendocrine carcinoma are based solely on tumor morphology; however, overlap in histologic and immunophenotypic features between the two types of carcinoma can potentially make their classification challenging. Accurate diagnosis of pulmonary neuroendocrine carcinomas is paramount for patient management, as clinical course and treatment differ between small cell and large cell neuroendocrine carcinoma. Molecular-genetic, transcriptomic, and proteomic data published over the past decade suggest that small cell and large cell neuroendocrine carcinomas are not homogeneous categories but rather comprise multiple groups of distinctive malignancies. Nuances in the susceptibility of small cell lung carcinoma subtypes to different chemotherapeutic regimens and the discovery of targetable mutations in large cell neuroendocrine carcinoma suggest that classification and treatment of neuroendocrine carcinomas may be informed by ancillary molecular and protein expression testing going forward. This review summarizes current diagnostic criteria, prognostic and predictive correlates of classification, and evidence of previously unrecognized subtypes of small cell and large cell neuroendocrine carcinoma.

Differential Orthopedia Homeobox expression in pulmonary carcinoids is associated with changes in DNA methylation

Limited number of tumor types have been examined for Orthopedia Homeobox (OTP) expression. In pulmonary carcinoids, loss of expression is a strong indicator of poor prognosis. Here, we investigated OTP expression in 37 different tumor types, and the association between OTP expression and DNA methylation levels in lung neuroendocrine neoplasms. We analyzed publicly available multi-omics data (whole-exome-, whole-genome-, RNA sequencing and Epic 850K-methylation array) of 58 typical carcinoids, 27 atypical carcinoids, 69 large cell neuroendocrine carcinoma and 51 small cell lung cancer patients and TCGA (The Cancer Genome Atlas) data of 33 tumor types. 850K-methylation analysis was cross-validated using targeted pyrosequencing on 35 carcinoids. We report bimodality of OTP expression in carcinoids (OTPhigh vs OTPlow group, likelihood-ratio test P = 1.5 × 10-2 ), with the OTPhigh group specific to pulmonary carcinoids while absent from all other cohorts analyzed. Significantly different DNA methylation levels were observed between OTPhigh and OTPlow carcinoids in 12/34 OTP infinium probes (FDR < 0.05 and β-value effect size > .2). OTPlow carcinoids harbor high DNA methylation levels as compared to OTPhigh carcinoids. OTPlow carcinoids showed a significantly worse overall survival (log-rank test P = .0052). Gene set enrichment analysis for somatically mutated genes associated with hallmarks of cancer showed robust enrichment of three hallmarks in the OTPlow group, that is, sustaining proliferative signaling, evading growth suppressor and genome instability and mutation. Together our data suggest that high OTP expression is a unique feature of pulmonary carcinoids with a favorable prognosis and that in poor prognostic patients, OTP expression is lost, most likely due to changes in DNA methylation levels.

Correlation of somatostatin receptor PET/CT imaging features and immunohistochemistry in neuroendocrine tumors of the lung: a retrospective observational study

PURPOSE

To correlate somatostatin receptor (SSTR) and proliferative activity profile (SSTR2, SSTR5, Ki-67) at immunohistochemistry (IHC) with SSTR-PET/CT imaging features in a retrospective series of lung neuroendocrine tumors (NET). Proliferative activity by Ki-67 and ¹⁸F-FDG-PET/CT parameters (when available) were also correlated.

METHODS

Among 551 patients who underwent SSTR-PET/CT with ⁶⁸Ga-DOTA-somatostatin analogs (SSA) between July 2011 and March 2020 for lung neuroendocrine neoplasms, 32 patients with a confirmed diagnosis of NET were included. For 14 of them, ¹⁸F-FDG-PET/CT was available. PET/CT images were reviewed by qualitative and semi-quantitative analyses. Immunohistochemistry for SSTR2, SSTR5, and Ki-67 was assessed. Inferential analysis was performed including kappa statistics and Spearman's rank correlation test.

RESULTS

Definitive diagnosis consisted of 26 typical carcinoids-G1 and six atypical carcinoids-G2. Positive SSTR2-IHC was found in 62.5% of samples while SSTR5-IHC positivity was 19.4%. A correlation between SSTR2-IHC and SSTR-PET/CT was found in 24/32 cases (75.0%, p = 0.003): 20 were concordantly positive, 4 concordantly negative. For positive IHC, 100% concordance with SSTR-PET/CT (both positive) was observed, while for negative IHC concordance (both negative) was 33.3%. In 8 cases, IHC was negative while SSTR-PET/CT was positive, even though with low-grade uptake in all but one. A significant correlation between SUV_max values at SSTR-PET/CT and the SSTR2-IHC scores was found, with low SUV_max values corresponding to negative IHC and higher SUV_max values to positive IHC (p = 0.002).

CONCLUSION

This retrospective study showed an overall good agreement between SSTR2-IHC and tumor uptake at SSTR-PET/CT in lung NETs. SSTR-PET/CT SUV_max values can be used as a parameter of SSTR2 density. Within the limits imposed by the relatively small cohort, our data suggest that SSTR2-IHC may surrogate SSTR-PET/CT in selected lung NET patients for clinical decision making when SSTR-PET/CT is not available.

Molecular imaging phenotyping for selecting and monitoring radioligand therapy of neuroendocrine neoplasms

Neuroendocrine neoplasia (NEN) is an umbrella term that includes a widely heterogeneous disease group including well-differentiated neuroendocrine tumours (NETs), and aggressive neuroendocrine carcinomas (NECs). The site of origin of the NENs is linked to the intrinsic tumour biology and is predictive of the disease course. It is understood that NENs demonstrate significant biologic heterogeneity which ultimately translates to widely varying clinical presentations, disease course and prognosis. Thus, significant emphasis is laid on the pre-therapy evaluation of markers that can help predict tumour behavior and dynamically monitors the response during and after treatment. Most well-differentiated NENs express somatostatin receptors (SSTRs) which make them appropriate for peptide receptor radionuclide therapy (PRRT). However, the treatment outcomes of PRRT depend heavily on the adequacy of patient selection by molecular imaging phenotyping not only utilizing pre-treatment SSTR PET but ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) PET to provide insights into the intra- or inter-tumoural heterogeneity of the metastatic disease. Molecular imaging phenotyping may go beyond patient selection and provide useful information during and post-treatment for monitoring of temporal heterogeneity of the disease and dynamically risk-stratify patients. In addition, advances in the understanding of genomic-phenotypic classifications of pheochromocytomas and paragangliomas led to an archetypical example in precision medicine by utilizing molecular imaging phenotyping to guide radioligand therapy. Novel non-SSTR based peptide receptors have also been explored diagnostically and therapeutically to overcome the tumour heterogeneity. In this paper, we review the current molecular imaging modalities that are being utilized for the characterization of the NENs with special emphasis on their role in patient selection for radioligand therapy.

Prognostic significance of laterality in lung neuroendocrine tumors

PURPOSE

Well-differentiated lung neuroendocrine tumors (Lu-NET) are classified as typical (TC) and atypical (AC) carcinoids, based on mitotic counts and necrosis. However, prognostic factors, other than tumor node metastasis (TNM) stage and the histopathological diagnosis, are still lacking. The current study is aimed to identify potential prognostic factors to better stratify lung NET, thus, improving patients' treatment strategy and follow-up.

METHODS

A multicentric retrospective study, including 300 Lung NET, all surgically removed, from Italian and Spanish Institutions.

RESULTS

Median age 61 years (13-86), 37.7% were males, 25.0% were AC, 42.0% were located in the lung left parenchyma, 80.3% presented a TNM stage I-II. Mitotic count was ≥2 per 10 high-power field (HPF) in 24.7%, necrosis in 13.0%. Median overall survival (OS) was 46.1 months (0.6-323), median progression-free survival (PFS) was 36.0 months (0.3-323). Female sex correlated with a more indolent disease (T1; N0; lower Ki67; lower mitotic count and the absence of necrosis). Left-sided primary tumors were associated with higher mitotic count and necrosis. At Cox-multivariate regression model, age, left-sided tumors, nodal (N) positive status and the diagnosis of AC resulted independent negative prognostic factors for PFS and OS.

CONCLUSIONS

This study highlights that laterality is an independent prognostic factors in Lu-NETs, with left tumors being less frequent but showing a worse prognosis than right ones. A wider spectrum of clinical and pathological prognostic factors, including TNM stage, age and laterality is suggested. These parameters could help clinicians to personalize the management of Lu-NET.

Diagnosis in Neuroendocrine Neoplasms: From Molecular Biology to Molecular Imaging

Simple Summary

Neuroendocrine neoplasms are a small group of malignancies with a diverse prognosis and behaviour. In order to offer an adequate treatment, physicians need to perform a proper diagnosis, staging and stratification. This review aims to help to integrate the information from pathology, immunohistochemistry, molecular biology and imaging to guide this process.

Abstract

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumours with a diverse behaviour, biology and prognosis, whose incidence is gradually increasing. Their diagnosis is challenging and a multidisciplinary approach is often required. The combination of pathology, molecular biomarkers, and the use of novel imaging techniques leads to an accurate diagnosis and a better treatment approach. To determine the functionality of the tumour, somatostatin receptor expression, differentiation, and primary tumour origin are the main determining tumour-dependent factors to guide treatment, both in local and metastatic stages. Until recently, little was known about the biological behaviour of these tumours. However, in recent years, many advances have been achieved in the molecular characterization and diagnosis of NENs. The incorporation of novel radiotracer-based imaging techniques, such as ⁶⁸Gallium-DOTATATE PET-CT, has significantly increased diagnostic sensitivity, while introducing the theragnosis concept, offering new treatment strategies. Here, we will review current knowledge and novelties in the diagnosis of NENs, including molecular biology, pathology, and new radiotracers.

Value of [68Ga]Ga-somatostatin receptor PET/CT in the grading of pulmonary neuroendocrine (carcinoid) tumours and the detection of disseminated disease: single-centre pathology-based analysis and review of the literature

BACKGROUND

Although most guidelines suggest performing a positron emission tomography/computed tomography (PET/CT) with somatostatin receptor (SSTR) ligands for staging of pulmonary carcinoid tumours (PC), only a limited number of studies have evaluated the role of this imaging tool in this specific patient population. The preoperative differentiation between typical carcinoid (TC) and atypical carcinoid (AC) and the extent of dissemination (N/M status) are crucial factors for treatment allocation and prognosis of these patients. Therefore, we performed a pathology-based retrospective analysis of the value of SSTR PET/CT in tumour grading and detection of nodal and metastatic involvement of PC and compared this with the previous literature and with [¹⁸F]FDG PET/CT in a subgroup of patients.

METHODS

SSTR PET/CT scans performed between January 2007 and May 2020 in the context of PC were included. If available, [¹⁸F]FDG PET/CT images were also evaluated. The maximum standardized uptake (SUV_max) values of the primary tumour, of the pathologically examined hilar and mediastinal lymph node stations, as well as of the distant metastases, were recorded. Tumoural SUV_max values were related to the tumour type (TC versus AC) for both SSTR and [¹⁸F]FDG PET/CT in diagnosing and differentiating both tumour types. Nodal SUV_max values were compared to the pathological status (N⁺ versus N^-) to evaluate the diagnostic accuracy of SSTR PET/CT in detecting lymph node involvement. Finally, a mixed model analysis of all pathologically proven distant metastatic lesions was performed.

RESULTS

A total of 86 SSTR PET/CT scans performed in 86 patients with PC were retrospectively analysed. [¹⁸F]FDG PET/CT was available in 46 patients. Analysis of the SUV_max values in the primary tumour showed significantly higher SSTR uptake in TC compared with AC (median SUV_max 18.4 vs 3.8; p = 0.003) and significantly higher [¹⁸F]FDG uptake in AC compared to TC (median SUV_max 5.4 vs 3.5; p = 0.038). Receiver operating characteristic (ROC) curve analysis resulted in an area under the curve (AUC) of 0.78 for the detection of TC on SSTR PET/CT and of 0.73 for the detection of AC on [¹⁸F]FDG PET/CT. A total of 267 pathologically evaluated hilar and mediastinal lymph node stations were analysed. ROC analysis of paired SSTR/[¹⁸F]FDG SUV_max values for the detection of metastasis of TC in 83 lymph node stations revealed an AUC of 0.91 for SSTR PET/CT and of 0.74 for [¹⁸F]FDG PET/CT (difference 0.17; 95% confidence interval - 0.03 to 0.38; p = 0.10). In a sub-cohort of 10 patients with 12 distant lesions that were pathologically examined due to a suspicious aspect on SSTR PET/CT, a positive predictive value (PPV) of 100% was observed.

CONCLUSION

Our findings confirm the higher SSTR ligand uptake in TC compared to AC and vice versa for [¹⁸F]FDG uptake. More importantly, we found a good diagnostic performance of SSTR PET/CT for the detection of hilar and mediastinal lymph node metastases of TC. Finally, a PPV of 100% for SSTR PET/CT was found in a small sub-cohort of patients with pathologically investigated distant metastatic lesions. Taken together, SSTR PET/CT has a very high diagnostic value in the TNM assessment of pulmonary carcinoids, particularly in TC, which underscores its position in European guidelines.

Clinic and genetic similarity assessments of atypical carcinoid, neuroendocrine neoplasm with atypical carcinoid morphology and elevated mitotic count and large cell neuroendocrine carcinoma

Background

Pulmonary neuroendocrine neoplasms can be divided into typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell (lung) carcinoma. According to the World Health Organization, these four neoplasms have different characteristics and morphological traits, mitotic counts, and necrotic status. Importantly, “a grey-zone” neoplasm with an atypical carcinoid-like morphology, where the mitotic rate exceeds the criterion of 10 mitoses per 2 mm², have still not been well classified. In clinical practice, the most controversial area is the limit of 11 mitoses to distinguish between atypical carcinoids and large cell neuroendocrine carcinomas.

Methods

Basic and clinical information was obtained from patient medical records. A series of grey-zone patients (n = 8) were selected for exploring their clinicopathological features. In addition, patients with atypical carcinoids (n = 9) and classical large cell neuroendocrine carcinomas (n = 14) were also included to compare their similarity to these neoplasms with respect to tumour morphology and immunohistochemical staining.

Results

We found that these grey-zone tumour sizes varied and affected mainly middle-aged and older men who smoked. Furthermore, similar gene mutations were found in the grey-zone neoplasms and large cell neuroendocrine carcinomas, for the mutated genes of these two are mainly involved in PI3K-Akt signal pathways and Pathways in cancer, including a biallelic alteration of TP53/RB1 and KEAP1.

Conclusions

Our findings indicate that neuroendocrine neoplasm with atypical carcinoid morphology and elevated mitotic counts is more similar to large cell neuroendocrine carcinoma than atypical carcinoid. Furthermore, this study may help improve diagnosing these special cases in clinical practice to avoid misdiagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09391-w.

Immune Checkpoint Blockade in Lung Carcinoids with Aggressive Behaviour: One More Arrow in Our Quiver?

Lung carcinoids are well-differentiated and low-/intermediate-grade neuroendocrine neoplasms of the lung. Given their relative rarity, and the paucity of data available from prospective studies, no global consensus exists on the systemic treatment of these tumours. In recent years, immune checkpoint inhibitors have revolutionized cancer management and are under evaluation in patients with diverse types of neuroendocrine neoplasms. The aim of this narrative review is to analyse all available data for the use of approved immune checkpoint inhibitors in patients with lung carcinoids. We performed an extensive search for relevant data sources and found five published articles, one meeting abstract, and nine registered clinical trials indicating a growing interest of researchers in this field, and providing preliminary evidence of efficacy for combined nivolumab plus ipilimumab and durvalumab plus tremelimumab regimens in the treatment of advanced and/or metastatic lung carcinoids.

The classification of neuroendocrine neoplasms of the lung and digestive system according to WHO, 5th Edition: similarities, differences, challenges & unmet needs

Neuroendocrine neoplasms (NENs) are a group of disease entities sharing common morphological, ultrastructural and immunophenotypical features, yet with distinct biological behavior and clinical outcome, ranging from benign to frankly malignant. Accordingly, a spectrum of therapeutic options for each single entity is available, including somatostatin analogues (SSA), mTOR-inhibitors, peptide receptor radionuclide therapy (PRRT), non-platinum and platinum chemotherapy. In the last few decades, several attempts have been made in order to (1) better stratify these lesions refining the pathological classifications, so as to obtain an optimal correspondence between the scientific terminology and, the predictive and prognostic features of each disease subtype, and (2) achieve a global Classification encompassing NENs arising at different anatomical sites. Aim of this review is to analyze, compare and discuss the main features and issues of the latest WHO Classifications of NENs of the lung and the digestive system, in order to point out the strengths and limitations of our current understanding of these complex diseases.

Bronchial Carcinoids: From Molecular Background to Treatment Approach

A better understanding of the genetic and molecular background of bronchial carcinoids (BCs) would allow a better estimation of the risk of disease progression and the personalization of treatment in cases of advanced disease. Molecular studies confirmed that lungs neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) are different entities; thus, no progression of NET to NEC is expected. In BCs, MEN1 gene mutations and deletions and decreased gene expression have been associated with a poor prognosis. ATRX mutation has also been linked to a shorter disease-specific survival. In terms of therapeutic targets, PI3K/AKT/mTOR pathway mutations have been described in 13% of typical carcinoids (TCs) and 39% of atypical carcinoids (ACs), representing a targetable mutation with kinase inhibitors. Regarding treatment, surgical resection is usually curative in localized BCs and adjuvant treatment is not routinely recommended. Multiple options for systemic therapy exist for patients with advanced BCs, although limited by a heterogeneity in the scientific evidence behind their use recommendation. These options include somatostatin analogues, everolimus, peptide receptor radionuclide therapy, chemotherapy, radiotherapy, antiangiogenic agents, and immunotherapy. In this article, we provide a comprehensive review about the molecular and genetic background of BCs, and about the treatment of local and metastatic disease, as well as the main paraneoplastic syndromes that have been associated with this tumor.

Prognosis of Patients with Bronchopulmonary Neuroendocrine Neoplasms in a Tertiary Neuroendocrine Tumor Centre of Excellence

INTRODUCTION

The European Neuroendocrine Tumor Society (ENETS) reports variables of prognostic significance in bronchopulmonary neuroendocrine neoplasms (BP-NENs). The aim of this study was to investigate prognostic factors, recurrence-free survival (RFS), and overall survival (OS) for patients with typical carcinoid (TC), atypical carcinoid (AC), and large-cell neuroendocrine carcinoma (LCNEC). Current follow-up practices vary as the evidence is sparse, and we aimed to explore the relevance of routine bronchoscopy in follow-up.

METHODS

This was a cohort study of 208 patients with BP-NENs followed at Aarhus University Hospital in 2008-2019. RFS and OS were determined using the Kaplan-Meier method for the variables such as primary tumor, primary treatment, smoking status, gender, and histological subtypes.

RESULTS

The study included 153 patients with TC, 29 with AC, and 26 with LCNEC. Median follow-up was 48 months. The majority of patients (n = 191) received surgical resection, of which 22 (11%) recurred over time. Seventeen patients had nonsurgical treatment, of which 10 (59%) progressed. The 5-year OS rate was 86% for operated and 9% for nonoperated patients (p < 0.05). Patients with TC had a 5-year OS of 90% compared with 63% and 39% for AC and LCNEC, respectively. As for prognostic factors, nonsmokers did not secure a significant difference in OS compared with current/previous smokers (p = 0.51). In the follow-up period, only 2 (9%) of the 22 recurrences were found on a routine bronchoscopy. Both of these recurrences were also found by diagnostic imaging.

CONCLUSIONS

Surgical treatment, especially, and diagnosis of TC were associated with a good prognosis. Furthermore, our data did not support routine bronchoscopy as part of a follow-up program for bronchial carcinoids.

Lung neuroendocrine neoplasms: recent progress and persistent challenges

This review summarizes key recent developments relevant to the pathologic diagnosis of lung neuroendocrine neoplasms, including carcinoids, small cell lung carcinoma (SCLC), and large cell neuroendocrine carcinoma (LCNEC). Covered are recent insights into the biological subtypes within each main tumor type, progress in pathological diagnosis and immunohistochemical markers, and persistent challenging areas. Highlighted topics include highly proliferative carcinoids and their distinction from small cell and large cell neuroendocrine carcinomas (NECs), the evolving role of Ki67, the update on the differential diagnosis of NEC to include thoracic SMARCA4-deficient undifferentiated tumors, the recent data on SCLC transcriptional subtypes with the emergence of POU2F3 as a novel marker for the diagnosis of SCLC with low/negative expression of standard neuroendocrine markers, and the update on the diagnosis of LCNEC, particularly in biopsies. There has been remarkable recent progress in the understanding of the genetic and expression-based profiles within each type of lung neuroendocrine neoplasm, and it is hoped that these insights will enable the development of novel diagnostic, prognostic, and predictive biomarkers to aid in the pathologic assessment of these tumors in the future.

Surgical Principles in the Management of Lung Neuroendocrine Tumors: Open Questions and Controversial Technical Issues

OPINION STATEMENT

Primary neuroendocrine tumors (NETs) of the lung represent a heterogeneous group of malignancies arising from the endocrine cells, involving different entities, from well differentiated to highly undifferentiated neoplasms. Because of the predominance of poorly differentiated tumors, advanced disease is observed at diagnosis in more than one third of patients making chemo- or chemoradiotherapy the only possible treatment. Complete surgical resection, as defined as anatomical resection plus systematic lymphadenectomy, becomes a reliable curative option only for that little percentage of patients presenting with stage I (N0) high-grade NETs. On the other hand, complete surgical resection is considered the mainstay treatment for localized low- and intermediate-grade NETs. Therefore, in the era of the mini-invasive surgery, their indolent behavior has suggested that parenchyma-sparing resections could be as adequate as the anatomical ones in terms of oncological outcomes, leading to discuss about the correct extent of resection and about the role of lymphadenectomy when dealing with highly differentiated NETs.

Endobronchial resection as a bridge to curative resection in patient with poor preoperative lung function secondary to an airway blocking endobronchial carcinoid tumour

We present a 70-year-old gentleman with chronic cough with haemoptysis found to have left lower zone collapse on imaging. The bronchoscopy showed an endobronchial mass histologically of a non-secreting atypical carcinoid. Poor baseline lung function excluded surgical resection, and instead, he successfully underwent a bronchoscopic debulking procedure which improved his FEV1 to 84% and DLCO 83% predicted. Unfortunately, the tumour regrew, but the calculated percentage predicted postoperative for FEV1 (64%), and DLCO (65%) enabled definitive surgical resection to take place. Surgical resection remains the definite curative option for localised endobronchial atypical carcinoid tumours. Achieving this in proximal endobronchial carcinoid tumour is a challenge. We described an endoscopic tumour debulking procedure as a bridge for curative surgical resection in a patient with an inoperable proximal atypical carcinoid tumour due to poor predicted postoperative lung function. We highlighted the need to assess predicted postoperative lung function with functional and quantitative perfusion methods to aid surgical planning. Debulking the tumour by endoscopy can be used as a conduit to curative surgical resection in bronchial carcinoid tumour. The choice of calculating the percentage predicted values by either or both methods must be individualised based on tumour location and the probability of converting a lobectomy to a pneumonectomy. This precautionary approach could evaluate the postoperative lung function and morbidity and mortality risk if considering a pneumonectomy. Endoscopic debulking can be a successful bridge to a curative surgical resection aided by comprehensive preoperative lung function tests to predict postoperative lung values

[Progress of Immune Checkpoint Inhibitors in the Treatment of Advanced Pulmonary Neuroendocrine Tumors]

Pulmonary neuroendocrine tumors (PNETs) are a kind of epithelial tumors originating from pulmonary neuroendocrine cells, accounting for about 20% of primary lung tumors, including typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma. The morphologic and clinical characteristics of these four types of PNETs are relatively highly heterogeneous. Immune checkpoint inhibitors (ICIs) have been shown robust antitumor activity in a variety of solid tumors. Treatment regimens of advanced PNETs have developed greatly in the past decade, but ICIs are still in their infancy in the field of PNETs. This review focuses on the landscape of current clinical trials and research as well as the situation of ICIs-related biomarkers in PNETs.
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Automated assessment of Ki-67 proliferation index in neuroendocrine tumors by deep learning

The Ki‐67 proliferation index (PI) is a prognostic factor in neuroendocrine tumors (NETs) and defines tumor grade. Analysis of Ki‐67 PI requires calculation of Ki‐67‐positive and Ki‐67‐negative tumor cells, which is highly subjective. To overcome this, we developed a deep learning‐based Ki‐67 PI algorithm (KAI) that objectively calculates Ki‐67 PI. Our study material consisted of NETs divided into training (n = 39), testing (n = 124), and validation (n = 60) series. All slides were digitized and processed in the Aiforia^® Create (Aiforia Technologies, Helsinki, Finland) platform. The ICC between the pathologists and the KAI was 0.89. In 46% of the tumors, the Ki‐67 PIs calculated by the pathologists and the KAI were the same. In 12% of the tumors, the Ki‐67 PI calculated by the KAI was 1% lower and in 42% of the tumors on average 3% higher. The DL‐based Ki‐67 PI algorithm yields results similar to human observers. While the algorithm cannot replace the pathologist, it can assist in the laborious Ki‐67 PI assessment of NETs. In the future, this approach could be useful in, for example, multi‐center clinical trials where objective estimation of Ki‐67 PI is crucial.

New Directions in Imaging Neuroendocrine Neoplasms

Purpose of Review

Accurate imaging is crucial for correct diagnosis, staging, and therapy of neuroendocrine neoplasms (NENs). The search for the optimal imaging technique has triggered rapid development in the field. This review aims at giving an overview on contemporary imaging methods and providing an outlook on current progresses.

Recent Findings

The discovery of molecular targets due to the overexpression of specific peptide hormone receptors on the NEN’s surface has triggered the development of multiple radionuclide imaging modalities. In addition to the established imaging technique of targeting somatostatin receptors, several alternative radioligands have been developed. Targeting the glucagon-like peptide-1 receptor by exendin-4 has a high sensitivity in localizing insulinomas. For dedifferentiated NENs, new molecular targets such as the C-X-C motif chemokine-receptor-4 have been evaluated. Other new targets involve the fibroblast activation protein and the cholecystokinin-2 receptors, where the ligand minigastrin opens new possibilities for the management of medullary thyroid carcinoma.

Summary

Molecular imaging is an emerging field that improves the management of NENs.

Adjuvant therapy for lung neuroendocrine neoplasms

Pulmonary neuroendocrine neoplasms (NENs) represent a minority of lung cancers and vary from slower growing pulmonary carcinoid (PC) tumors to aggressive small cell lung cancer (SCLC). While SCLC can account for up to 15% of lung cancer, PCs are uncommon and represent about 2% of lung cancers. Surgical resection is the standard of care for early-stage PCs and should also be considered in early stage large cell neuroendocrine carcinoma (LCNEC) and SCLC. Adjuvant treatment is generally accepted for aggressive LCNEC and SCLC, however, less well established for PCs. Guidelines admit a lack of trials to support a high-level recommendation for adjuvant therapy. This manuscript will discuss the role for adjuvant therapy in NENs and review the available literature.

Well-Differentiated Bronchopulmonary Neuroendocrine Tumors: More Than One Entity

INTRODUCTION

Until now, well-differentiated bronchopulmonary neuroendocrine tumors (bpNET) occurring either sporadically (sp-bpNET) or in the context of multiple endocrine neoplasia type 1 (MEN1) and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are regarded as similar entities. However, in contrast to sp-bpNET: MEN1-related and DIPNECH-related bpNET rarely metastasize or lead to bpNET-related death. We aimed to describe and compare the course of the disease of sp-bpNET, DIPNECH- and MEN1-related bpNET.

METHODS

All patients with histologically confirmed MEN1-related bpNET from the DutchMEN Study Group database (1990-2017), patients with resected sp-bpNET and DIPNECH patients referred to a Dutch European Neuroendocrine Tumor Society center between 2000 and 2018 were included. Fisher's exact test was used for comparison between groups. The primary end point was disease-specific mortality (DSM). Kaplan-Meier and logrank test were used to compare survival. Cox regression was used to identify risk factors for DSM in the sp-bpNET subgroup.

RESULTS

We included 112 sp-bpNET, 29 MEN1, and 27 DIPNECH patients. Tumor classification was similar across subgroups. A total of 20 patients (18%) with sp-bpNET died because of bpNET, compared with none in the MEN1 group and DIPNECH group. Median disease-specific survival was 12.3 (confidence interval: 6.3-18.3) years for patients with sp-bpNET, and not estimable for the other subgroups (p < 0.001). Differences in baseline characteristics did not explain worse survival in sp-bpNET. Tumor classification and age at diagnosis were independent risk factors for DSM in sp-bpNET.

CONCLUSIONS

Patients with sp-bpNET have a significantly higher DSM compared with MEN1 or DIPNECH-related bpNET, unexplained by differences in baseline characteristics. This implies that not all bpNET are similar entities.

Optimal Cut-Off Values of the Positive Lymph Node Ratio and the Number of Removed Nodes for Patients Receiving Resection of Bronchopulmonary Carcinoids: A Propensity Score-Weighted Analysis of the SEER Database

Background

Although lymph node dissection (LND) has been commonly used for patients with bronchopulmonary carcinoids (PCs), the prognostic values of the positive lymph node ratio (PLNR) and the number of removed nodes (NRN) remain unclear.

Methods

Patients with resected PCs were identified in the Surveillance, Epidemiology, and End Results (SEER) database (2010–2015). The optimal cut-off values of the PLNR and NRN were determined by X-tile. The inverse probability of treatment weighting (IPTW) method was used to reduce the selection bias. IPTW-adjusted Kaplan-Meier curves and Cox proportional hazards models were used to compare the overall survival (OS) and cancer-specific survival (CSS) of patients in different PLNR and NRN groups.

Results

The study included 1622 patients. The optimal cut-off values of the PLNR and NRN for survival were 13% and 13, respectively. In both Kaplan-Meier analysis and univariable Cox proportional hazards regression analysis before IPTW, a PLNR ≥13% was significantly associated with worse OS (HR = 3.364, P<0.001) and worse CSS (HR = 7.874, P<0.001). These findings were corroborated by the IPTW-adjusted Cox analysis OS (HR = 2.358, P = 0.0275) and CSS (HR = 8.190, P<0.001) results. An NRN ≥13 was not significantly associated with worse OS in either the Kaplan-Meier or Cox analysis before or after IPTW adjustment. In the Cox proportional hazards analysis before and after IPTW adjustment, an NRN ≥13 was significantly associated with worse CSS (non-IPTW: HR = 2.216, P=0.013; IPTW-adjusted: HR = 2.162, P=0.024).

Conclusion

A PLNR ≥13% could predict worse OS and CSS in patients with PCs and might be an important complement to the present PC staging system. Extensive LND with an NRN ≥13 might have no therapeutic value for OS and may even have an adverse influence on CSS. Its application should be considered on an individual basis.

Surufatinib for the treatment of advanced extrapancreatic neuroendocrine tumors

Introduction: Surufatinib (also known as HMPL-012, sulfatinib) is a novel oral tyrosine kinase inhibitor (TKI), which has the dual activity of anti-angiogenesis and immune regulation. In December 2020, surufatinib was approved as a monotherapy for unresectable locally advanced or metastatic, progressive nonfunctioning, well differentiated (grade 1 or 2) extrapancreatic neuroendocrine tumors (epNETs) in China.Areas covered: In this paper, the chemical properties, mechanism of action, pharmacokinetics, clinical efficacy, safety, and tolerability of surufatinib for treatment of advanced extrapancreatic NETs are introduced in detail. We performed a systematic review of the literature in PubMed and the following keywords were used: 'surufatinib,' 'sulfatinib' and 'HMPL-012.'Expert opinion: Surufatinib is a potent, selective, and small-molecule TKI that targets vascular endothelial growth factor receptor (VEGFR), fibroblast growth factor receptor 1 (FGFR1) and colony stimulating factor 1 receptor (CSF1R). Surufatinib showed an acceptable safety profile and encouraging antitumor activity in patients with advanced epNETs. The most frequently observed adverse events (AEs) were hypertension and proteinuria. Surufatinib provides a new treatment option for patients with advanced epNETs. More clinical trials of surufatinib are ongoing to develop a combination of therapy strategies and new indications for malignancies.

Clinical-Pathologic Challenges in the Classification of Pulmonary Neuroendocrine Neoplasms and Targets on the Horizon for Future Clinical Practice

Diagnosing a pulmonary neuroendocrine neoplasm (NEN) may be difficult, challenging clinical decision making. In this review, the following key clinical and pathologic issues and informative molecular markers are being discussed: (1) What is the preferred outcome parameter for curatively resected low-grade NENs (carcinoid), for example, overall survival or recurrence-free interval? (2) Does the WHO classification combined with a Ki-67 proliferation index and molecular markers, such as OTP and CD44, offer improved prognostication in low-grade NENs? (3) What is the value of a typical versus atypical carcinoid diagnosis on a biopsy specimen in local and metastatic disease? Diagnosis is difficult in biopsy specimens and recent observations of an increased mitotic rate in metastatic carcinoid from typical to atypical and high-grade NEN can further complicate diagnosis. (4) What is the (ir)relevance of morphologically separating large cell neuroendocrine carcinoma (LCNEC) SCLC and the value of molecular markers (RB1 gene and pRb protein or transcription factors NEUROD1, ASCL1, POU2F3, or YAP1 [NAPY]) to predict systemic treatment outcome? (5) Are additional diagnostic criteria required to accurately separate LCNEC from NSCLC in biopsy specimens? Neuroendocrine morphology can be absent owing to limited sample size leading to missed LCNEC diagnoses. Evaluation of genomic studies on LCNEC and marker studies have identified that a combination of napsin A and neuroendocrine markers could be helpful. Hence, to improve clinical practice, we should consider to adjust our NEN classification incorporating prognostic and predictive markers applicable on biopsy specimens to inform a treatment outcome-driven classification.

Evaluation of the reporting quality of clinical practice guidelines on lung cancer using the RIGHT checklist

BACKGROUND

In recent years, the number of clinical practice guidelines (CPGs) for lung cancer has increased, but the quality of these guidelines has not been systematically assessed so far. Our aim was to assess the reporting quality of CPGs on lung cancer published since 2018 using the International Reporting Items for Practice Guidelines in Health Care (RIGHT) instrument.

METHODS

We systematically searched the major electronic literature databases, guideline databases and medical society websites from January 2018 to November 2020 to identify all CPGs for small cell and non-small cell lung cancer (NSCLC). The search and extraction were completed using standardized forms. The quality of included guidelines was evaluated using the RIGHT statement. We present the results descriptively, including a stratification by selected determinants.

RESULTS

A total of 49 CPGs were included. The mean proportion across the guidelines of the 22 items of the RIGHT checklist that were appropriately reported was 57.9%. The items most common to be poorly reported were quality assurance (item 17) and description of the role of funders (item 18b), both of which were reported in only one guideline. The proportions of items within each of the seven domains of the RIGHT checklist that were correctly reported were Basic information 75.9%; background 83.2%; evidence 44.5%; recommendations 55.4%; review and quality assurance 12.2%; funding and declaration and management of interests 42.9%; and other information 38.1%. The reporting quality of guidelines did not differ between publication years. CPGs published in journals with impact factor >30 tended to be best reported.

CONCLUSIONS

Our results revealed that reporting in CPGs for lung cancer is suboptimal. Particularly the declaration of funding and quality assurance are poorly reported in recent CPGs on lung cancer.