Tumorlets, multicentric carcinoids, lymph-nodal metastases, and long-term behavior in bronchial carcinoids

Two Different Tumors and Lung Aspergilloma: An Uncommon Etiopathogenic Association

Several cases reported in the literature have confirmed the link between pulmonary aspergillosis and various malignant diseases. Furthermore, it has been observed that the correlation between carcinoid tumor and lung adenocarcinoma is quite uncommon. The etiopathogenic mechanisms underlying these correlations remain poorly defined. We present the case of a patient with three of these diseases: a lung adenocarcinoma with a lepidic pattern, a typical carcinoid, and pulmonary aspergillosis. An additional noteworthy aspect of this case pertains to the timely detection of both lung malignancies. Thus, the necessity for further investigation to ascertain the pathogenic connection among the three diseases is underscored. The ultimate objective is to enhance the prognosis of individuals diagnosed with lung cancer, which is a prevailing malignant disease on a global scale.

Rachel score: a nomogram model for predicting the prognosis of lung neuroendocrine tumors

BACKGROUND

Lung NET, classified in typical carcinoids (TC) and atypical carcinoids (AC), are highly heterogeneous in their biology and prognosis. The histological subtype and TNM stage are well-established prognostic factors for lung NET. In a previous work by our group, we demonstrated a significant impact of laterality on lung NET survival outcomes.

MATERIALS AND METHODS

We developed a nomogram that integrates relevant prognostic factors to predict lung NET outcomes. By adding the scores for each of the variables included in the model, it was possible to obtain a prognostic score (Rachel score). Wilcoxon non-parametric statistical test was applied among parameters and Harrell's concordance index was used to measure the models' predictive power. To test the discriminatory power and the predictive accuracy of the model, we calculated Gonen and Heller concordance index. Time-dependent ROC curves and their area under the curve (AUC) were used to evaluate the models' predictive performance.

RESULTS

By applying Rachel score, we were able to identify three prognostic groups (specifically, high, medium and low risk). These three groups were associate to well-defined ranges of points according to the obtained nomogram (I: 0-90, II: 91-130; III: > 130 points), providing a useful tool for prognostic stratification. The overall survival (OS) and progression free survival (PFS) Kaplan-Meier curves confirmed significant differences (p < 0.0001) among the three groups identified by Rachel score.

CONCLUSIONS

A prognostic nomogram was developed, incorporating variables with significant impact on lung NET survival. The nomogram showed a satisfactory and stable ability to predict OS and PFS in this population, confirming the heterogeneity beyond the histopathological diagnosis of TC vs AC.

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.

Anatomic Pulmonary Resection is Associated With Improved Survival in Typical Carcinoid Lung Tumor Patients

BACKGROUND

The optimal extent of resection for a patient with a typical carcinoid tumor has been controversial. Studies suggest that wedge resection is an adequate oncologic operation for this tumor type.

MATERIALS AND METHODS

We analyzed the National Cancer Database to determine an optimal surgical resection for patients with a typical carcinoid tumor. We determined the number of patients who had typical carcinoid tumors. We then performed a survival analysis of the propensity-matched group of patients having a pathologic stage I typical carcinoid tumor who had undergone anatomic pulmonary resection (lobectomy and segmentectomy) or wedge resection.

RESULTS

A total of 10,265 patients met the inclusion and exclusion criteria: 8956 (87%) had a typical carcinoid tumor, while 1309 patients (13%) had an atypical carcinoid tumor. Among patients with typical carcinoid tumors, there were 7163 patients (80%) who underwent anatomic pulmonary resection (6755 patients with lobectomy, 94% and 408 patients with segmentectomy, 6%) and 1793 patients (20%) who underwent wedge resection. In this cohort, patients who had an anatomic resection had significantly improved 5-y survival compared to patients who had wedge resection (91% versus 84%, P < 0.001). In the propensity score-matched group of stage I typical carcinoid tumors (n = 1348), the patients who had an anatomic resection had significantly improved survival compared to patients who had wedge resections (89% versus 85%, P = 0.01) at 5 y.

CONCLUSIONS

The anatomic resection compared to wedge resection was associated with improved survival in patients with early-stage typical carcinoid lung cancer. Surgically fit patients should be considered for anatomic resection for typical carcinoid tumors.

Prognostic Significance of Pulmonary Multifocal Neuroendocrine Proliferation With Typical Carcinoid

BACKGROUND

The clinical significance of multifocal pulmonary neuroendocrine proliferation (MNEP), including tumorlets and pulmonary neuroendocrine cell hyperplasia, in association with typical carcinoid (TC), is still debated.

METHODS

We evaluated a retrospective series of TC with long-term follow-up data prospectively collected from 2 institutions and compared the outcome between TC alone and MNEP plus TC. Several baseline covariates were imbalanced between the MNEP plus TC and TC groups; therefore, we conducted 1:1 propensity score matching and inverse probability of treatment weighting in the full sample. In the matched group, the association of clinical, respiratory, and work-related factors with the group was determined through univariable and multivariable conditional logistic regression analysis.

RESULTS

A total of 234 TC patients underwent surgery: 41 MNEP plus TC (17.5%) and 193 TC alone (82.5%). In the MNEP plus TC group, older age (P < .001), peripheral tumors (P = .0032), smaller tumor size (P = .011), and lymph node spread (P = .02) were observed compared with the TC group. Relapses occurred in 8 patients in the MNEP plus TC group (19.5%) and 7 in the TC group (3.6%). After matching, in 36 pairs of patients, a significantly higher 5-year progression-free rate was observed for the TC group (P < .01). Similar results were observed using inverse probability of treatment weighting in the full sample. The odds of being in the MNEP plus TC group was higher for those with work-related exposure to inhalant agents (P = .008), asthma or bronchitis (P = .002), emphysema, fibrosis, and inflammatory status (P = .032), or micronodules on the chest computed tomography scan and respiratory insufficiency (P = .036).

CONCLUSIONS

The association with MNEP seems to represent a clinically and prognostic relevant factor in TC. Hence, careful preoperative workup, systematic pathologic evaluation, including nontumorous lung parenchyma, and long-term postoperative follow-up should be recommended in these patients.

Pulmonary neuroendocrine carcinoid tumors: Is there a predictive role to the Ki 67 index?

INTRODUCTION

There are several factors predicting evolution in carcinoid tumors (CT) to date including the Ki67 role.

AIMS

The aim of this study is to identify a KI67 cut-off point for a population of CT and determine its prognostic implication in global and disease-free survival.

METHODS

Hematoxylin-eosin slides of 102 CT were revised. The percentage of cells expressing Ki 67 was determined manually.

STATISTICAL ANALYSIS

The variables were compared with the t-test or the Wilcoxon test according to their distribution, the categorical ones with Chi-square or Fisher's test. The best cut-off point was established by constructing receiver operating characteristic curves, then using that value as a dichotomous variable.

RESULTS

72 typical carcinoids (TC) and 30 atypical carcinoids (AC) were analyzed; 66% were female. Median age (TC 38 vs. AC 51, P = 0.001), Ki67 expression (TC 0.63 vs. AC 2, P = 0.003), tumor size (TC 2.5 vs. AC 2.6, P = 0.001), the percentage relapse (TC 3.4% vs. AC 23%, P = 0.006), and the number of deaths (TC 1 vs. AC 4, P = 0.042) were significantly higher in the AC subgroup. The best cut-off point for Ki 67 was 0.755 (area under the curve AUC 0.564, 95% confidence interval 0.270-0.857), with no significant differences found in the disease-free and overall survival curves when considering values < or ≥ at the established cut-off point. The best cut-off point of the Ki-67 when exclusively analyzing AC was 1.18. When using this value as a predictive variable, a marginal statistical association was observed between Ki-67 expression, mortality (P = 0.077), and the frequency of relapses (P = 0.054).

CONCLUSIONS

Histological type is the best predictor of prognosis in the carcinoid tumor group. In the AC subgroup, the marginal association between mortality, frequency of relapses and Ki values 67 ≥ 1.18 has clinical relevance future analyses are required to determine the real predictive value of this variable.

Long-term survival and recurrence after resection of bronchopulmonary carcinoids: A single-center cohort study of 236 patients

OBJECTIVE

The aim of this study was to determine overall survival and recurrence-free survival after resection of bronchopulmonary carcinoids by means of predominantly minimally invasive surgery and lung-sparing resections. In addition, we aimed to identify prognostic factors for overall survival.

MATERIALS AND METHODS

Retrospective review of consecutive patients operated for bronchopulmonary carcinoids between January 2009 and October 2020 identified from a prospectively collected database.

RESULTS

A total of 236 patients representing 240 cases of bronchopulmonary carcinoids were included. Of these, 212 (88.3 %) were typical carcinoids, while 28 (11.7 %) were atypical carcinoids. A Video-Assisted Thoracoscopic Surgery (VATS) approach was used in 75 % of cases. There was no 30-day mortality. The median follow-up was 5.6 years for overall survival and 4.7 years for recurrence-free survival. 5- and 10-year overall survival rates were 89 % and 71 %, while 5- and 10-year recurrence-free survival rates were 84 % and 71 %. Patients with atypical carcinoids had significantly reduced overall survival and recurrence-free survival rates (HR 3.4; 95 % CI 1.5-7.6; p = 0.003 and HR 5.4; 95 % CI 2.6-11.4; p < 0.001). Independent predictors of overall survival included atypical carcinoid (HR 2.7; 95 % CI 1.2-6.0; p = 0.018) and age > 60 years (HR 2.9; 95 % CI 1.2-7.3; p = 0.021).

CONCLUSION

Surgery for bronchopulmonary carcinoids by means of predominantly VATS and lung-sparing resections provides favorable long-term survival. Atypical carcinoids and age > 60 years are independent predictors of poor overall survival.

Pulmonary carcinoid presenting in pregnancy with an unusual radiological feature

Pulmonary carcinoid tumours are a rare form of malignancy that often present with clinical heterogeneity and are challenging to diagnose. Diagnosis during pregnancy is further complicated by delays in imaging and procedures to minimise harm to the fetus. This case describes a primigravid healthcare worker who was diagnosed with pulmonary carcinoid in her first trimester of pregnancy, with particular focus on the unique radiological findings of subpleural blebs as a feature.

[Diagnostic and therapeutic management of operable bronchopulmonary carcinoid tumours]

INTRODUCTION

Bronchial carcinoid tumours (CT), divided into typical carcinoid (TC) or atypical carcinoid (AC), are rare tumours whose therapeutic management remains unspecified.

METHODS

Retrospective study collecting cases of bronchial CT operated at the thoracic surgery department of Abderrahmane-Mami hospital of Ariana and recruited from the pneumology departments of Northern Tunisia, during a 12-year period.

RESULTS

Ninety patients were collected (74 cases of TC and 16 cases of AC). The mean age was 45 years and the sex ratio H/F=0.5. The chest X-ray was normal in 11 cases, as well as flexible bronchoscopy in seven cases. The tumour was classified: stage IA (10 cases), IIA (28 cases), IIB (31 cases), IIIA (15 cases) and IIIB (six cases). Surgery resulted in a complete resection in 78 patients, an extensive resection in six patients, and a conservative resection in six patients. Adjuvant chemotherapy was given in 10 patients. The survival was 84% at five years and 42% at 10 years.

CONCLUSION

The prognosis of CT depends directly on the histological subtype. It is excellent for TC after complete resection, unlike ACs that are similar to well-differentiated bronchial carcinomas.

Endobronchial Carcinoids: Surgical Outcome in 100 Consecutive Patients and Factors Affecting Lung Preservation

Bronchial carcinoids are slow-growing tumours of the neuroendocrine family. Most of them have a benign course with excellent outcome after complete resection. Due to their location in the primary bronchi, adequate resection with lung preservation requires considerable technical expertise. In this paper we present our surgical experience with endobronchial carcinoids and analyse the factors that predict possibility of lung preservation surgery. Retrospective analysis of a prospectively maintained database of patients operated for endobronchial carcinoids for the period March 2012 to September 2019 was carried out. Demographic factors and peri-operative variables were recorded and analysed. Factors that influence surgical outcome and possibility of lung preservation surgery were analysed. A total of 137 patients underwent surgery for resection of carcinoid tumours, out of which 100 had endobronchial carcinoids whereas 37 had peripheral carcinoids. The surgical procedure in 100 patients with endobronchial carcinoids included 14 left main bronchus sleeve resections, 13 pneumonectomies (7 right sided and 6 left sided), 10 right lower and middle bi-lobectomies, 10 lobectomies (4 left upper, 2 left lower and 4 right upper), and 53 sleeve lobectomies (18 left upper lobe sleeves, 8 left lower lobe sleeves, 20 right upper lobe sleeves, 5 right middle lobe sleeves and 2 right lower lobe sleeve lobectomies). There was no operative mortality. Median tumour size was 3.9 cm (range 5-130 mm). On univariate analysis, longer duration of symptoms was associated with poor surgical outcomes. On multivariate analysis, tumour in the main bronchus, duration of disease < 3 months (p = 0.006), left-sided disease (p = 0.03), and presence of healthy distal lung parenchyma (p < 0.001) were associated with successful lung preservation. Majority of endobronchial carcinoid tumours can be managed with lung-sparing procedures with minimal morbidity and mortality and excellent immediate and short-term outcomes. Early referral and experience of team performing these complex procedures are the key to success.

Surgical management of bronchopulmonary carcinoids: A single center experience

Introduction:

Bronchopulmonary carcinoids are uncommon tumors with relatively indolent biological behavior but a distinct malignant potential. Surgery is the mainstay of treatment. Our aim was to study preoperative characteristics, surgical approaches, and outcome in patients with bronchopulmonary carcinoid tumors.

Patients and Methods:

This retrospective study was done in the Department of Surgical Oncology of a Tertiary Teaching Hospital of North India. The case records of all the patients who underwent surgical treatment for lung neoplasms and were diagnosed to have bronchopulmonary carcinoids were reviewed. Details concerning the clinical presentation, preoperative therapy, operative procedure, postoperative complications, and outcome were retrieved from the case records.

Results:

Sixteen patients who underwent surgical treatment were found to have bronchopulmonary carcinoids on histopathological examination. The median age of the patients was 34 years (range 18–62 years). There were 11 men and five women. All patients were symptomatic, and the median duration of symptoms was 12 months (range 6–72 months) before presentation. Six patients had received antitubercular treatment before presentation, and one patient had been treated with chemotherapy due to misdiagnosis. Surgical procedures included six pneumonectomies (one with carinoplasty), four bilobectomies, three lobectomies, and three bronchoplastic procedures (two with lobectomy and one with bilobectomy). There was no postoperative mortality; three patients had morbidity in the form of lobar collapse, prolonged pleural collection, and surgical site infection. With a median follow-up time of 11 months (range 2–85 months), all the 16 patients are alive and disease-free.

Conclusions:

Delayed presentation and misdiagnosis of bronchial carcinoid are major concerns in North India. Adequate surgical resection can be performed without undue morbidity and is associated with good long-term results.

Diagnostic and Management Pathways for Pulmonary Carcinoid Tumours in the United Kingdom: Results from the National Lung Neuroendocrine Tumour Pathway Project

There is inconsistency among published guidelines for the optimal diagnostic and management pathways for patients with typical (TC) or atypical (AC) pulmonary carcinoid tumours. We conducted a UK-wide clinician survey to assess current practice for the diagnosis, management, and follow-up of patients with TC/AC and descriptively compared management between European Neuroendocrine Tumor Society (ENETS) accredited centres of excellence (CoE) and nonaccredited centres (non-CoE). Twenty-seven clinicians (10 CoE; 17 non-CoE) participated. Computed tomography of thorax, abdomen, and pelvis was the most commonly reported diagnostic tool (96% of respondents), and bone scans and gallium somatostatin receptor scintigraphy positron emission tomography (SRS PET) were the least commonly reported (30% and 37% of respondents, respectively). Adjuvant therapy is considered for resected TC/AC by <5% of respondents for patients with stage N0 M0 AC or TC, up to 48% of respondents for patients with AC with R1 disease. Somatostatin analogues were the most commonly reported first-line treatment (63% of respondents), and chemotherapy was the most commonly reported second-line therapy and third-line therapy (33% and 41%, respectively) for unresectable and metastatic disease. Reported frequency of initial follow-up after primary surgery ranged from every 2 months to annual, and total follow-up duration ranged from 2 years to indefinite depending on disease type (TC/AC) and stage. For most diagnostic investigations, the highest reported frequency of use was in CoE, most notably gallium SRS PET (70% CoE vs. 18% non-CoE respondents). 93% of respondents (100% CoE; 88% non-CoE) reported having neuroendocrine tumour- (NET-) specialist multidisciplinary team meetings at their centre; 59% (90% CoE; 41% non-CoE) had a NET Clinical Nurse Specialist (CNS) and 48% (80% CoE; 29% non-CoE) had a lung NET patient database. The survey results suggest variability between UK centres in diagnostic pathways and management of patients with TC/AC and suggest that CoE may be able to offer an improved service to patients.

Pulmonary Neuroendocrine Tumors

Pulmonary neuroendocrine tumors represent a morphologic spectrum of tumors from the well-differentiated typical carcinoid tumor, to the intermediate-grade atypical carcinoid tumor, to the high-grade neuroendocrine carcinomas composed of small-cell carcinoma and large-cell neuroendocrine carcinoma. The addition of immunohistochemistry in diagnostics is helpful and often essential, especially in the classification of large-cell neuroendocrine carcinoma. The importance of the intermediate-grade atypical carcinoid group is underscored by the impact of this diagnosis on therapy. The distinction of pulmonary small-cell carcinoma from large-cell neuroendocrine carcinoma, despite both being in the high-grade group, is of relevance to the therapeutic approach to these tumor types.

Neuroendocrine Tumors of the Lung: Updates and Diagnostic Pitfalls

Neuroendocrine tumors of the lung constitute approximately 20% of all primary lung tumors and include typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma. Given their morphologic overlap with diverse mimics, neuroendocrine tumors of the lung can be diagnostically challenging. This review discusses the clinical, histologic, immunophenotypic, and molecular features of pulmonary neuroendocrine tumors, along with common diagnostic pitfalls and strategies for avoidance.

Endobronchial and surgical treatment of pulmonary carcinoid tumors: A systematic literature review

The treatment of pulmonary carcinoid has changed over the last decades. Although surgical resection is still the gold standard, minimally invasive endobronchial procedures have emerged as a parenchyma sparing alternative for tumors located in the central airways. This review was performed to identify the optimal treatment strategy for pulmonary carcinoid, with a particular focus on the feasibility and outcome of parenchyma sparing techniques versus surgical resection. A systematic review of the literature was carried out using MEDLINE, Embase and the Cochrane databases, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Two separate searches of publications in endobronchial and surgical treatment in patients with pulmonary carcinoid, were performed. Outcomes were overall survival, disease free survival, recurrence rate, complications, quality of life, and healthcare costs. Combining the two main searches for endobronchial therapy and surgical therapy yielded 3111 records. Finally, 43 studies concerning surgical treatment and 9 studies related to endobronchial treatment for pulmonary carcinoid were included. Assessment of included studies showed that lymph node involvement, histological grade, tumor location and tumor diameter were identified as poor prognostic factors and seem to be important for patients with pulmonary carcinoid. For patients with a more favorable prognosis, tumor location and tumor diameter are important factors that can help decide on the optimal treatment strategy. Centrally located small intraluminal pulmonary carcinoids, without signs of metastasis can be treated with minimally invasive alternatives such as endobronchial treatment or parenchyma sparing surgical resection. Patients with parenchyma sparing resections should be followed with long term follow up to exclude recurrence of disease. In a multidisciplinary setting, it should be determined whether individual patients are eligible for parenchyma sparing procedures or anatomical resection. Overall evidence is of low quality and future studies should focus on prospective trials in the treatment of pulmonary carcinoid.

[Systemic Therapy for Low-grade Pulmonary Neuroendocrine Tumor]

肺部是神经内分泌肿瘤（neuroendocrine tumor, NET）的第二好发部位。肺类癌包括典型类癌和不典型类癌，属于低级别神经内分泌肿瘤。这一类肿瘤由于发病率较低，目前尚未得到广大医务工作者的重视。但有效的治疗不仅能提高患者的远期生存，还能控制患者症状，改善生活质量。本文分别阐述肺低级别神经内分泌肿瘤的流行病学和病理学特点、早期患者的治疗策略以及进展期患者的治疗策略。早期患者应当尽早进行手术治疗。进展期患者治疗方式包括化疗、SSAs、mTOR抑制剂、肽受体介导的放射性核素治疗、生物治疗以及靶向治疗。目前的研究结论大多来自其他部位的NETs研究外推而来，仍需针对肺低级别神经内分泌肿瘤患者进行特异性临床试验加以证实。

Unmet Medical Needs in Pulmonary Neuroendocrine (Carcinoid) Neoplasms

Pulmonary carcinoids (PCs) display the common features of all well-differentiated neuroendocrine neoplasms (NEN) and are classified as low- and intermediate-grade malignant tumours (i.e., typical and atypical carcinoid, respectively). There is a paucity of randomised studies dedicated to advanced PCs and management principles are drawn from the larger gastroenteropancreatic NEN experience. There is growing evidence that NEN anatomic subgroups have different biology and different responses to treatment and, therefore, should be investigated as separate entities in clinical trials. In this review, we discuss the existing evidence and limitations of tumour classification, diagnostics and staging, prognostication, and treatment in the setting of PC, with focus on unmet medical needs and directions for the future.

Pulmonary carcinoids - analysis of early and long-term surgical treatment outcomes in a group of 90 patients

Introduction

Over the years, pulmonary carcinoids have been treated as locally malignant tumors because of the favorable prognosis. It is currently known that the clinical course of the disease is mainly dependent on the carcinoid subtype.

Aim

To analyze the early and long-term surgical treatment outcomes for typical and atypical carcinoids.

Material and methods

A total of 90 patients were treated surgically for pulmonary carcinoid tumors in the years 2007–2015. Typical carcinoids were diagnosed in 69 (77%) cases, while atypical carcinoids – in 21 (23%); 67 patients underwent lobectomy, 3 – sleeve lobectomy, 9 – bilobectomy, 2 – pneumonectomy, 1 – segmentectomy, and 8 – wedge resection.

Results

None of the patients died in the postoperative period. Complications occurred in 14.4% of patients. The most common complications included: arrhythmias (5.6%), prolonged air leak (3.3%), and residual pneumothorax (3.3%). Among the 21 patients with atypical carcinoids, N1 metastasis was found in 1 (4.8%) patient, while N2 – in 5 (23.8%) patients. In the group of 69 patients with typical carcinoids, N1 metastasis was revealed in 7 (10.1%) patients and N2 metastases – in 2 (2.9%) patients. The probability of 5-year survival in patients with typical and atypical carcinoids was 96% and 83%, respectively. During the follow-up period 7 (7.8%) patients, including 6 with atypical carcinoids, experienced local recurrence; distant metastasis occurred in 8 (8.9%) cases, including 6 with atypical carcinoids.

Conclusions

Although radical surgical treatment provides excellent long-term outcomes, it should be noted that patients with pulmonary carcinoids (especially with the atypical subtype) may experience local recurrence and distant metastases even many years after surgery.

Management of pulmonary neuroendocrine tumors

Neuroendocrine tumors (NETs) of the lung are divided into 4 major types: small cell lung cancer (SCLC), large cell neuroendocrine carcinoma (LCNEC), atypical carcinoid (AC) or typical carcinoid (TC). Each classification has distinctly different treatment paradigms, making an accurate initial diagnosis essential. The inconsistent clinical presentation of this disease, however, makes this difficult. The objective of this manuscript is to detail the diagnosis and management of the well differentiated pulmonary carcinoid (PC) tumors. A multidisciplinary approach to work up and treatment should be utilized for each patient. A multimodal radiological work-up is used for diagnosis, with contrast enhanced CT predominantly utilized and functional imaging techniques. A definitive diagnosis is based on tissue findings. Surgical management remains the mainstay of therapy and can be curative. In those with advanced disease, medical treatments consist of somatostatin analog (SSA) therapy, targeted therapy, chemotherapy or peptide receptor radionuclide therapy. SSAs are the standard of care in those with metastatic NETs, using either Octreotide long acting repeatable (LAR) or lanreotide as reasonable options, despite a scarcity of prospective data in PCs. Targeted therapies consist of everolimus which is approved for use in PCs, with various studies showing mixed results with other targeted agents. Additionally, radionuclide therapy may be used and has been shown to increase survival and to reduce symptoms in some studies. Prospective trials are needed to determine other strategies that may be beneficial in PCs as well as sequencing of therapy. Successful diagnosis and optimal treatment relies on a multidisciplinary approach in patients with lung NETs. Clinical trials should be used in appropriate patients.

Lung neuroendocrine tumors: pathological characteristics

Lung neuroendocrine tumors (NETs) are a heterogeneous family of neoplasms comprising four histologic types, namely typical and atypical carcinoid (TC and AC), large-cell neuroendocrine and small cell carcinoma (SCC). Classification criteria include the number of mitoses per 2 mm2, the occurrence and extent of necrosis, cytological and histological features and immunohistochemistry for neuroendocrine markers. The classification system and the diagnostic workflow of lung NETs are apparently easy to apply and well established. However, several unresolved issues still exist in classification and pathological characterization of these tumors, probably because inter-observer diagnostic reproducibility remains disappointing, likely due to inconsistency in recognizing necrosis, mitoses and cytological details, especially in small biopsy or cytological materials. Furthermore, the lack of strong prognostic and grading criteria leads to the incomplete interpretation of some rare intermediate entities that stand in between AC and large cell neuroendocrine carcinoma (LCNEC) categories.

The components of somatostatin and ghrelin systems are altered in neuroendocrine lung carcinoids and associated to clinical-histological features

BACKGROUND

Lung carcinoids (LCs) are rare tumors that comprise 1-5% of lung malignancies but represent 20-30% of neuroendocrine tumors. Their incidence is progressively increasing and a better characterization of these tumors is required. Alterations in somatostatin (SST)/cortistatin (CORT) and ghrelin systems have been associated to development/progression of various endocrine-related cancers, wherein they may become useful diagnostic, prognostic and therapeutic biomarkers.

OBJECTIVES

We aimed to evaluate the expression levels of ghrelin and SST/CORT system components in LCs, as well as to explore their putative relationship with histological/clinical characteristics.

PATIENTS AND METHODS

An observational retrospective study was performed; 75 LC patients with clinical/histological characteristics were included. Samples from 46 patients were processed to isolate mRNA from tumor and adjacent non-tumor region, and the expression levels of SST/CORT and ghrelin systems components, determined by quantitative-PCR, were compared to those of 7 normal lung tissues.

RESULTS

Patient cohort was characterized by mean age 53±15 years, 48% males, 34% with tobacco exposure; 71.4/28.6% typical/atypical carcinoids, 21.7% incidental tumors, 4.3% functioning tumors, 17.7% with metastasis. SST/CORT and ghrelin system components were expressed at variable levels in a high proportion of tumors, as well as in adjacent non-tumor tissues, while a lower proportion of normal lung samples also expressed these molecules. A gradation was observed from normal non-neoplastic lung tissues, non-tumor adjacent tissue and LCs, being SST, sst4, sst5, GHS-R1a and GHS-R1b overexpressed in tumor tissue compared to normal tissue. Importantly, several SST/CORT and ghrelin system components displayed significant correlations with relevant clinical parameters, such as necrosis, peritumoral and vascular invasion, or metastasis.

CONCLUSION

Altogether, these data reveal a prominent, widespread expression of key SST/CORT/ghrelin system components in LCs, where they display clinical-histological correlations, which could provide novel, valuable markers for NET patient management.

Bronchial and Thymic Carcinoid Tumors

Bronchial and thymic carcinoids are rare. We present epidemiologic data and potential risk factors. The approach to bronchial and thymic carcinoid patients is discussed, from the initial diagnosis and evaluations to treatment. These malignancies follow staging systems of their site of origin. Because bronchial and thymic carcinoids are rare, we use many treatment strategies that have been demonstrated in gastrointestinal and pancreatic neuroendocrine tumors. The lack of information regarding efficacy in bronchial and thymic carcinoids, as well as the scarcity of therapeutic options available, demands the importance of clinical trials that include these patients.

Pulmonary Neuroendocrine Tumors: Part I. Spectrum and Characteristics of Tumors

Pulmonary neuroendocrine tumors arise from Kulchitzky cells of the bronchial mucosa and include typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma, and small cell lung cancer. These tumors have a variable growth rate that determines their presentation and prognosis. Typical carcinoid has the lowest growth rate and better prognosis; in contrast, small cell lung cancer is an aggressive tumor with a very poor prognosis. Although there are some overlapping histologic features between these tumors, clinical, imaging, and immunohistochemical markers are useful in the differentiation of pulmonary neuroendocrine tumors. The treatment options differ on the basis of histologic characteristics. In this article, we aim to describe the spectrum of neuroendocrine tumors of the lung, except for small cell lung cancer, and their clinical, pathologic, and imaging findings, with a focus on treatment options.

Differential expression and prognostic value of the chemokine receptor CXCR4 in bronchopulmonary neuroendocrine neoplasms

Introduction

For many tumors, the overexpression of the chemokine receptor CXCR4 is associated with increased malignancy and poor patient outcomes. However, comprehensive data for neuroendocrine neoplasms of the lung are still lacking.

Methods

CXCR4 expression was evaluated in a panel of bronchopulmonary neuroendocrine neoplasms (BP-NEN) comprising typical carcinoids (n = 26), atypical carcinoids (n = 30), and small cell lung cancers (SCLC, n = 34). Samples were analyzed by immunohistochemistry using the novel monoclonal rabbit anti-human CXCR4 antibody UMB-2 and by qRT-PCR. The expression was correlated with clinical data and overall patient survival.

Results

CXCR4 was predominantly localized at the plasma membrane of the tumor cells. CXCR4 was expressed with a high intensity in almost all of the 30 SCLC samples. In contrast, it was detected infrequently and with low intensity in the typical carcinoid and atypical carcinoid samples. There was a significant correlation between the immunohistochemistry and qRT-PCR data. Additionally, there was a significant negative relationship between CXCR4 expression and overall survival.

Conclusions

With increasing malignancy, BP-NEN clearly differ in the extent of CXCR4 expression. As in other tumor entities, CXCR4 overexpression significantly correlates with negative patient outcome. Due to its particular high expression rate in SCLC, CXCR4 may serve as a promising new target for diagnostic and pharmacological intervention as well as for peptide receptor-based radionuclide therapy.

Diagnosis and management of typical and atypical lung carcinoids

An estimated 20% to 30% of all neuroendocrine tumours originate in the bronchial tree and lungs. According to the 2015 World Health Organization categorization, these tumours are separated into four subtypes characterized by increasing biological aggressiveness: typical carcinoid, atypical carcinoid, large-cell neuroendocrine carcinoma and small-cell carcinoma. Although typical and atypical lung carcinoids account for less than 1-5% of all pulmonary malignancies, the incidence of these neoplasms has risen significantly in recent decades. Surgery is the treatment of choice for loco-regional disease but for advanced lung carcinoids there is no recognized standard of care and successful management requires a multidisciplinary approach. The aim of this review is to provide a useful guide for the clinical management of lung carcinoids.

[Metastatic bronchial carcinoid tumors]

Bronchial carcinoids are uncommon pulmonary neoplasms and represent 1 to 2 % of all lung tumors. In early stage of disease, the mainstay and only curative treatment is surgery. Bronchial carcinoids are generally regarded as low-grade carcinomas and metastatic dissemination is unusual. The management of the metastatic stage is not currently standardized due to a lack of relevant studies. As bronchial carcinoids and in particular their metastatic forms are rare, we apply treatment strategies that have been evaluated in gastrointestinal and pancreatic neuroendocrine tumors. However, bronchial carcinoids have their own characteristic. A specific therapeutic feature of these metastatic tumors is that they require a dual approach: both anti-secretory for the carcinoid syndrome, and anti-tumoral.

Cardiothoracic manifestations of neuroendocrine tumours

Cardiothoracic neuroendocrine tumour (NET) manifestations encompass a vast disease spectrum. Pulmonary neuroendocrine tumours represent a range of tumour grade and differentiation characteristics from pre-malignant diffuse neuroendocrine cell hyperplasia, well-differentiated, low-grade carcinoid tumours with excellent outcomes, through to high-grade small-cell lung carcinoma and large-cell neuroendocrine carcinoma with poor prognoses. Rarer thymic NETs represent a similarly wide neoplastic spectrum. Cardiac carcinoid is a paraneoplastic manifestation of the carcinoid syndrome and often the cause of mortality in NETs with hepatic metastases. Cardiothoracic NET manifestations are reviewed herein from a radiologists' perspective, discussing the diverse clinical presentations, spectrum of neoplastic and paraneoplastic manifestations, imaging features and treatment options.

Classification of lung neuroendocrine tumors: lights and shadows

Neuroendocrine tumors of the lung are classified into low-grade typical and intermediate-grade atypical carcinoids, and high-grade poorly differentiated neuroendocrine carcinomas of the large and small cell types. This scheme is strongly predictive of patients' prognosis but relies on few and scarcely reproducible pathological parameters (namely mitotic count and assessment of the presence of necrosis), which have been demonstrated to affect the inter-observer agreement of the classification. Moreover, tumor and nodal staging schemes are not specific for lung carcinoids, at variance with neuroendocrine tumors of the gastro-entero-pancreatic system, despite these tumors have specific features that strongly differ from conventional lung cancer. Finally, there is no grading for lung neuroendocrine neoplasms and prognostication, as well as the definition of treatment modalities and clinical strategies, which are based on tumor histotypes, only. However, literature data indicate that the evaluation of Ki-67 proliferation index may be a reliable and useful tool to determine the biological and clinical behavior of neuroendocrine tumors, with special reference to carcinoids, both in pre-operative and surgical samples.

Somatostatin receptor PET/CT in restaging of typical and atypical lung carcinoids

Background

To assess the role of somatostatin receptor (SR) PET/CT using Ga-68 DOTATOC or DOTATATE in staging and restaging of typical (TC) and atypical (AC) lung carcinoids.

Methods

Clinical and PET/CT data were retrospectively analyzed in 27 patients referred for staging (N = 5; TC, N = 4; AC, N = 1) or restaging (N = 22; TC, N = 8; AC, N = 14). Maximum standardized uptake value (SUVmax) of SR-positive lesions was normalized to the SUVmax of the liver to generate SUVratio; SR PET was compared to contrast-enhanced (ce) CT. The classification system proposed by Rindi et al. (Endocr Relat Cancer. 2014;21(1):1-16, 2014) was used for classification of patients in TC and AC groups.

Results

Only 18/27 patients were found to have metastases on PET/CT. Of the 186 lesions, 101 (54.3 %) were depicted on both PET and CT, 53 (28.5 %) lesions only on CT, and 32 (17.2 %) only on PET. SUVratio of lesions was significantly higher in AC as compared to TC (p < 0.001). In patients referred for restaging, additional findings on PET lead to upstaging with change in management strategy in 5/22 (22.7 %) patients (AC, N = 5; TC, N = 1). In four patients (all AC) referred for restaging and in one patient (TC) referred for staging, additional findings on CT missed on PET lead to correct staging.

Conclusions

Typical and atypical carcinoid patients have complex patterns of metastases which make it necessary to combine functional SR PET and contrast-enhanced CT for appropriate restaging. In patients referred for restaging SR, PET may have a relevant impact on treatment strategy in up to 22.7 of patients with typical and atypical lung carcinoids.

Diagnosis and treatment of bronchopulmonary neuroendocrine tumours: State of the art

Bronchopulmonary neuroendocrine tumours (BP-NET) are a heterogeneous population of neoplasms with different pathology, clinical behaviour and prognosis compared to the more common lung cancers. The management of BP-NET patients is largely based on studies with a low level of evidence and extrapolation of data obtained from more common types of neuroendocrine tumours. This review reflects our view of the current state of the art of diagnosis and treatment of patients with BP-NET.

Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practice for typical and atypical pulmonary carcinoids

BACKGROUND

Pulmonary carcinoids (PCs) are rare tumors. As there is a paucity of randomized studies, this expert consensus document represents an initiative by the European Neuroendocrine Tumor Society to provide guidance on their management.

PATIENTS AND METHODS

Bibliographical searches were carried out in PubMed for the terms 'pulmonary neuroendocrine tumors', 'bronchial neuroendocrine tumors', 'bronchial carcinoid tumors', 'pulmonary carcinoid', 'pulmonary typical/atypical carcinoid', and 'pulmonary carcinoid and diagnosis/treatment/epidemiology/prognosis'. A systematic review of the relevant literature was carried out, followed by expert review.

RESULTS

PCs are well-differentiated neuroendocrine tumors and include low- and intermediate-grade malignant tumors, i.e. typical (TC) and atypical carcinoid (AC), respectively. Contrast CT scan is the diagnostic gold standard for PCs, but pathology examination is mandatory for their correct classification. Somatostatin receptor imaging may visualize nearly 80% of the primary tumors and is most sensitive for metastatic disease. Plasma chromogranin A can be increased in PCs. Surgery is the treatment of choice for PCs with the aim of removing the tumor and preserving as much lung tissue as possible. Resection of metastases should be considered whenever possible with curative intent. Somatostatin analogs are the first-line treatment of carcinoid syndrome and may be considered as first-line systemic antiproliferative treatment in unresectable PCs, particularly of low-grade TC and AC. Locoregional or radiotargeted therapies should be considered for metastatic disease. Systemic chemotherapy is used for progressive PCs, although cytotoxic regimens have demonstrated limited effects with etoposide and platinum combination the most commonly used, however, temozolomide has shown most clinical benefit.

CONCLUSIONS

PCs are complex tumors which require a multidisciplinary approach and long-term follow-up.

Medical treatment of advanced thoracic neuroendocrine tumors

Thoracic Neuroendocrine Tumors (TNETs) range from the more indolent behavior of the well-differentiated to the highly aggressive poorly differentiated forms. A clinical approach totally different in terms of diagnosis and treatment is therefore required. Chemotherapy and radiotherapy are the treatments of choice in poorly differentiated, whereas biological and target therapy, peptide receptor radionuclide therapy (PPRT) and temozolomide have shown efficacy in small series or in the subgroup analysis of larger trials in well differentiated. However, no specific trials have been performed before this year. The first large, prospective, randomized trial (LUNA trial) entirely dedicated to TNET is ongoing at the time of this publication.

Thoracic and duodenopancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1: natural history and function of menin in tumorigenesis

Mutations of the multiple endocrine neoplasia type 1 (MEN1) gene lead to loss of function of its protein product menin. In keeping with its tumor suppressor function in endocrine tissues, the majority of the MEN1-related neuroendocrine tumors (NETs) show loss of heterozygosity (LOH) on chromosome 11q13. In sporadic NETs, MEN1 mutations and LOH are also reported, indicating common pathways in tumor development. Prevalence of thymic NETs (thNETs) and pulmonary carcinoids in MEN1 patients is 2-8%. Pulmonary carcinoids may be underreported and research on natural history is limited, but disease-related mortality is low. thNETs have a high mortality rate. Duodenopancreatic NETs (dpNETs) are multiple, almost universally found at pathology, and associated with precursor lesions. Gastrinomas are usually located in the duodenal submucosa while other dpNETs are predominantly pancreatic. dpNETs are an important determinant of MEN1-related survival, with an estimated 10-year survival of 75%. Survival differs between subtypes and apart from tumor size there are no known prognostic factors. Natural history of nonfunctioning pancreatic NETs needs to be redefined because of increased detection of small tumors. MEN1-related gastrinomas seem to behave similar to their sporadic counterparts, while insulinomas seem to be more aggressive. Investigations into the molecular functions of menin have led to new insights into MEN1-related tumorigenesis. Menin is involved in gene transcription, both as an activator and repressor. It is part of chromatin-modifying protein complexes, indicating involvement of epigenetic pathways in MEN1-related NET development. Future basic and translational research aimed at NETs in large unbiased cohorts will clarify the role of menin in NET tumorigenesis and might lead to new therapeutic options.

Analysis on the characteristics and prognosis of pulmonary neuroendocrine tumors

OBJECTIVE

To retrospectively review the clinical characteristics and analyze the prognostic factors of Chinese patients with pulmonary neuroendocrine tumors.

MATERIALS AND METHODS

The clinical data of 176 patients with pulmonary neuroendocrine tumors in Chinese PLA General Hospital from Mar., 2000 to Oct., 2012 were retrospectively analyzed. The parameters were evaluated by univariate and multivariate analysis, including the gender, age, smoking history, family history, TNM staging, localization (central or peripheral), tumor size, nodal status, histological subtype and treatment (operation or non-operation).

RESULTS

There were 23 patients with typical carcinoids (TC) (13.1%), 41 with atypical carcinoids (AC) (23.3%), 10 with large cell neuroendocrine carcinoma (LCNEC) (5.7%) and 102 with small cell lung cancer (SCLC) (57.9%). The median follow-up time was 64.5 months for AC, 38 months for LCNEC and 27 months for SCLC. The typical carcinoid censored data was 18 (more than 50% of the patients), so the median follow-up time was not obtained, and actuarial 5-year survivals for TC, AC, LCNEC and SCLC were 75.1%, 51.7%, 26.7% and 38.8%, respectively. COX univariate analysis revealed that the age (P=0.001), histological subtype (P=0.005), nodal status (P=0.000), treatment (P=0.000) and TNM staging (P=0.000) were the prognostic factors of the patients with pulmonary neuroendocrine tumors, whereas its multivariate analysis showed that only the age(P=0.001), TNM staging (P=0.002) and treatment (P=0.000) were independent prognostic factors.

CONCLUSIONS

Radical surgery remains the treatment of choice, and is the only curative option. The age, TNM staging and treatment are confirmed to be the independent prognostic factors in multivariable models for pulmonary neuroendocrine tumors.

Diagnosis and treatment of neuroendocrine lung tumors

Pulmonary neuroendocrine tumors (PNT) encompass a broad spectrum of tumors including typical carcinoid (TC) and atypical (AC) tumors, large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC). Although no variety can be considered benign, AC and TC have a much lower metastatic potential, are usually diagnosed in early stages, and most are candidates for surgical treatment. Several chemotherapy (CT) regimens are available in the case of recurrence or in advanced stages, although scientific evidence is insufficient. LCNEC, which is currently classified alongside large-cell carcinomas, have molecular features, biological behavior and CT sensitivity profile closely resembling SCLC. Pathological diagnosis is often difficult, despite the availability of immunohistochemical techniques, and surgical specimens may be necessary. The diagnostic tests used are similar to those used in other lung tumors, with some differences in the optimal tracer in positron emission tomography. The new TNM classification is useful for staging these tumors. Carcinoid syndrome, very rare in PNT, may cause symptoms that are difficult to control and requires special therapy with somatostatin analogs and other drugs. Overall, with the exception of SCLC, new trials are needed to provide a response to the many questions arising with regard to the best treatment in each lineage and each stage.

Prognostic factors in neuroendocrine tumours of the lung: a single-centre experience

OBJECTIVES

To assess the independent prognostic role of histological subtypes, tumour size and lymph nodal involvement upon survival in lung neuroendocrine tumours (NETs).

METHODS

A retrospective search of the database of the Department of Thoracic Surgery (Turin, Italy) identified 157 patients operated on for a newly diagnosed NET between January 1995 and December 2011. Multivariable Cox models were used to analyse predictors of overall survival and progression-free survival.

RESULTS

According to histology, 71 (45.2%) were typical carcinoids (TCs), 35 (22.3%) atypical carcinoids (ACs), 37 (23.6%) large-cell neuroendocrine carcinomas (LCNCs) and 14 (8.9%) small-cell lung carcinomas (SCLCs). After a median follow-up time of 6.5 years, 60 patients died and 73 had a recurrence or died. The overall 5-, 10- and 15-year survival rates were 64%, 53% and 46%, respectively. Older age, histology (ACs, LCNCs and SCLCs vs TCs) and lymph nodal involvement were confirmed to be independent negative prognostic factors in the multivariable models for overall survival and progression-free survival.

CONCLUSIONS

Tumour histology and lymph nodal involvement are definitively the predominant and relevant factors influencing survival. ACs showed an intermediate prognosis between TCs and poorly differentiated NETs.

Natural history of gastro-entero-pancreatic and thoracic neuroendocrine tumors. Data from a large prospective and retrospective Italian epidemiological study: the NET management study

BACKGROUND

The few epidemiological data available in literature on neuroendocrine tumors (NET) are mainly based on Registry databases, missing therefore details on their clinical and natural history.

AIM

To investigate epidemiology, clinical presentation, and natural history of NET.

DESIGN AND SETTING

A large national retrospective survey was conducted in 13 Italian referral centers. Among 1203 NET, 820 originating in the thorax (T-NET), in the gastro-enteropancreatic tract (GEP-NET) or metastatic NET of unknown primary origin (U-NET) were enrolled in the study.

RESULTS

93% had a sporadic and 7% a multiple endocrine neoplasia type 1 (MEN1)-associated tumor; 63% were GEP-NET, 33% T-NET, 4% U-NET. Pancreas and lung were the commonest primary sites. Poorly differentiated carcinomas were <10%, all sporadic. The incidence of NET had a linear increase from 1990 to 2007 in all the centers. The mean age at diagnosis was 60.0 ± 16.4 yr, significantly anticipated in MEN1 patients (47.7 ± 16.5 yr). Association with cigarette smoking and other non-NET cancer were more prevalent than in the general Italian population. The first symptoms of the disease were related to tumor burden in 46%, endocrine syndrome in 23%, while the diagnosis was fortuity in 29%. Insulin (37%) and serotonin (35%) were the most common hormonal hypersecretions. An advanced tumor stage was found in 42%, more frequently in the gut and thymus. No differences in the overall survival was observed between T-NET and GEP-NET and between sporadic and MEN1-associated tumors at 10 yr from diagnosis, while survival probability was dramatically reduced in U-NET.

CONCLUSIONS

The data obtained from this study furnish relevant information on epidemiology, natural history, and clinico-pathological features of NET, not available from the few published Register studies.

[Diagnosis and therapy of bronchopulmonary carcinoid tumors]

支气管肺类癌是罕见的肺部肿瘤，总体生长缓慢、预后尚可。根据其临床特征往往可以推测支气管肺类癌的诊断和亚型并指导治疗。其中年轻、CT表现为中心型肿瘤且无肺门或纵隔淋巴结肿大的病例，典型类癌的可能性较大。此亚型远处转移几率小，在手术治疗前除胸增强CT外可以不进行其它的常规术前分期检查。中心型肿瘤临床怀疑纵隔淋巴结累及或周围型肿瘤临床怀疑肺门纵隔淋巴结累及的病例，可能为不典型类癌。此亚型应做全面术前评估和分期。累及纵隔淋巴结的不典型类癌预后相对较差，应行多学科积极治疗。支气管肺类癌虽然其生物学特性不活跃，但均为恶性肿瘤，放化疗效果差，手术切除是最主要的治疗手段。彻底切除肿瘤、最大限度保留正常的肺组织是此类肺肿瘤外科治疗的基本目标。

Radical mediastinal nodal removal improves disease-free survival for pulmonary low-grade malignant tumors

PURPOSE

To investigate the prognostic role of radical lymph node dissection in treatment for pulmonary Low Grade Malignant Tumors (LGMTs); specifically, on the extent of nodal removal and its impact on long-term survival.

METHODS

A total of 93 LGMTs cases underwent surgical resection and were histopathologically confirmed. Overall survival rates and disease-free survival were respectively calculated according to the extent of lymph node resection and histopathological grades of tumors. Risk factors of nodal involvement and survival predictors were calculated via multivariate analysis. Life table, Kaplan-Meier, and Cox regression models were used for the statistical analysis.

RESULTS

Thirty-eight cases of carcinoid, 17 adenoid cystic carcinomas, and 38 mucoepidermoid carcinomas were included in the current study. Twenty-one cases were high-grade and 72 were low-grade. A total of 813 lymph nodes were removed, at an average of 8.7±5.4 nodes per patient. The numbers of harvested nodes were 11.8±4.5, in the study group via radical nodal removal and 4.0±2.4 nodes per patient in the nodal sampling group. Eleven cases showed lymph nodal involvement (5 mediastinal and 6 hilar lymph node metastasis). No significant differences of overall survival was found among the different histological types (p=0.939), or the extent of nodal removal (p=0.971). Meanwhile, there was a significant difference of disease-free survival (DFS) rates according to the extent of nodal removal (5-YS: 97% of radical nodal dissection vs. 78% of nodal sampling, p=0.038). Overall survival and disease-free survival were closely associated with histological grading (OS: 78% of high grade vs. 97% of low grade, p=0.001; DFS: 57% of high grade vs. 97% of low grade, p<0.0001).

CONCLUSIONS

Radical lymph node dissection improved disease-free survival for pulmonary low-grade malignant tumors, although no obvious improvement on overall survival was noticed. Histological grade was the most important prognostic factor in LGMTs.