Improvement in TNM staging of pulmonary neuroendocrine tumors requires histology and regrouping of tumor size

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.

Prognosis of Unresected vs Resected Small Pulmonary Carcinoid Tumors

BACKGROUND

Previous studies have shown that overall survival after lung resection for pulmonary carcinoid tumors is favorable. It is unclear what the prognosis is for observation rather than resection for small carcinoid tumors.

METHODS

We queried the National Cancer Database to identify patients presenting with primary pulmonary carcinoid tumors between 2004 and 2017. We included patients with small (<3 cm) primary pulmonary carcinoids, who were observed or underwent a lung resection. To minimize confounding by indication, we used propensity score matching, while accounting for age, sex, race, insurance type, Charlson-Deyo comorbidity score, typical and atypical histology, tumor size, and year of diagnosis. We used Kaplan-Meier survival analyses to compare 5-year overall survival in the matched cohorts.

RESULTS

Of 8435 patients with small pulmonary carcinoids, 783 (9.3%) underwent observation and 7652 (91%) underwent surgical resection. After propensity score matching, surgical resection was associated with improved 5-year overall survival (66% vs 81%, P < .001). No significant difference in overall survival was found between wedge and anatomic resection (88% vs 88%, P = .83). In patients undergoing resection, lymph node sampling at the time of wedge and anatomic resection increased 5-year overall survival (90% vs 86%, P = .0042; 88% vs 82%, P = .04, respectively).

CONCLUSIONS

Surgical resection of small pulmonary carcinoids is associated with improved survival compared with observation. When surgical resection is performed, wedge and anatomic resection result in similar survival, and lymph node sampling improves survival.

Development and Validation of Prognostic Nomograms for Periampullary Neuroendocrine Neoplasms: A SEER Database Analysis

(1) Background: Periampullary neuroendocrine neoplasms (NENs) are rare tumors that lack a prognostic prediction model. We aimed to design comprehensive and effective nomograms to predict prognosis; (2) Methods: Univariate and multivariate Cox analyses were used to screen out significant variables for the construction of the nomograms. The discrimination and calibration of the nomograms were carried out using calibration plots, concordance indices (C-indices), and area under time-dependent receiver operating characteristic curves (time-dependent AUCs). Decision curve analysis (DCA) was used to compare the clinical applicability of the nomograms, TNM (Tumor- Node-Metastasis) stage, and SEER stage; (3) Results: The independent risk factors for overall survival (OS) and cancer-specific survival (CSS) of patients with periampullary NENs included age, tumor size, histology, differentiation, N stage, M stage, and surgery, which were used to construct the nomograms. The calibration curves and C-indices showed a high degree of agreement between the predicted and actual observed survival rates. The AUCs displayed good calibration and acceptable discrimination of the nomograms. Additionally, the DCA curves indicated that the nomograms showed better clinical applicability; (4) Conclusions: We developed and validated nomogram prognostic models for patients with periampullary NENs. The nomograms provided insightful and applicable tools to evaluate prognosis.

Angioside: The role of Angiogenesis and Hypoxia in Lung Neuroendocrine Tumours According to Primary Tumour Location in Left or Right Parenchyma

Well-differentiated lung neuroendocrine tumours (Lu-NETs), classified as typical (TC) and atypical (AC) carcinoids, represent 30% of NETs. Angiogenesis plays an essential role in NET development and progression. A higher vascular network is a marker of differentiation, with positive prognostic implications. Materials and Methods: We retrospectively evaluated microvessel density (MVD) by CD34 immunohistochemical (IHC) staining and hypoxia by IHC staining for Hypoxia-inducible factor 1α (HIF-1α), comparing right- and left-lung parenchyma in 53 lung NETs. Results: The median age was 66 years (39−81), 56.6% males, 24.5% AC, 40.5% left-sided tumours and 69.8% TNM stage I. The mitotic count was <2/10 per 10 HPF in 79.2%, and the absence of necrosis in 81.1%, 39.6% with Ki67, was ≤2%. The MVD, the number of vessels and the average vessel area median values were significantly higher in the right than the left parenchyma (p: 0.025, p: 0.019, p: 0.016, respectively). Hypoxia resulted present in 14/19 (73.6%) left tumours and in 10/20 (50%) right tumours in the parenchyma (p: 0.129). Conclusions: This study suggests a biological rationale for a different angiogenesis and hypoxia according to the Lu-NETs’ location. In our study, left primary tumours were less vascularized and most likely to present hypoxia than right primary tumours. This finding could have potentially useful prognostic and predictive implications for Lu-NETs.

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.

External Validation of a Prognostic Score for Survival in Lung Carcinoids

Background: A prognostic score including T-dimension, age, histology and lymph node ratio was previously proposed in absence of an external validation dataset. The aim of the current study was to validate the proposed prognostic score using an independent dataset. Methods: Data of patients with lung carcinoids, who underwent surgical resection and lymphadenectomy in five institutions from 1 January 2005 to 31 December 2019, were retrospectively analyzed. Two risk groups were created based on the following data: age, histology, node ratio and pT for disease-free survival (DFS); age, sex, node ratio and pT for overall survival (OS). The previously proposed score was validated, identifying two groups of patients: a high risk (HRG) and low risk (LRG) group. Results: The final analysis was conducted on 283 patients. Regarding DFS, 230 (81.3%) patients were assigned to the LRG and 53 (18.7%) to the HRG. Considering OS, 268 (94.7%) were allocated in the LRG and 15 (5.3%) in the HRG. The 5-year DFS was 92.7% in the LRG vs. 67% in the HRG (p < 0.001) while the 5-year OS was 93.6% in the LRG vs. 86.2% in the HRG (p = 0.29) with clear curve separation. Conclusion: Our analysis confirmed the validity of the composite score for DFS in lung carcinoids. Regarding OS, statistical significance was not reached because of a low number of deaths and patients in the HRG.

The Role of Conventionally Fractionated Radiotherapy and Stereotactic Radiotherapy in the Treatment of Carcinoid Tumors and Large-Cell Neuroendocrine Cancer of the Lung

The occurrence of neuroendocrine tumors among the diagnosed neoplasms is extremely rare and is associated with difficulties in undertaking effective therapy due to the histopathological differentiation of individual subtypes and the scarce clinical data and recommendations found in the literature. The choice of treatment largely depends not only on its type, but also on the location and production of excess hormones by the tumor itself. Common therapeutic approaches include surgical removal of the tumor, the use of chemotherapy, targeted drug therapy, peptide receptor radionuclide therapy, and the use of radiation therapy. This article reviews the current knowledge on the classification and application of radiotherapy in the treatment of lung NETs. Case reports were presented in which treatment with conventional radiotherapy, radical and palliative radiochemotherapy, as well as stereotactic fractionated radiotherapy in the treatment of typical (TC) and atypical (AT) lung carcinoids and large cell neuroendocrine carcinoma (LCNC) were used. We hope that the solutions presented in the literature will allow many radiation oncologists to make the best, often personalized decisions about the therapeutic qualifications of patients.

Prognostic score for survival with pulmonary carcinoids: the importance of associating clinical with pathological characteristics

OBJECTIVES

Lung carcinoids (LCs) are staged using the non-small-cell lung cancer tumour/node/metastasis staging system; the possibility of an LC-specific staging system is still being debated. The goal of our study was to construct a composite prognostic score for LC.

METHODS

From January 2002 to December 2014, data from 293 patients who underwent surgical treatment for LC in 7 research institutes were retrospectively analysed. A panel of established prognostic factors in addition to lymph node metastasis patterns (single/multiple N1-N2 station, skip metastasis, lobe specific), numbers of lymph nodes resected and the ratio between the numbers of metastatic lymph nodes and the numbers of lymph nodes resected (node ratio) were correlated to overall survival (OS) and disease-free survival (DFS). The log-hazard ratio (HR), obtained from the Cox model, was used to derive weighting factors for a continuous prognostic index, designed to identify differential outcome risks. The score was dichotomized according to maximally selected log-rank statistics.

RESULTS

Pathological analysis showed typical carcinoids in 223 (76.1%) and atypical carcinoids in 70 (23.9%) patients; the tumour/node/metastasis pattern was stage I in 72.4%, stage II in 18.1%, stage III in 9.5% and stage IV in 0.03% cases. The median numbers of lymph nodes resected was 12 (range 0-53); hilar and mediastinal node metastases were identified in 14% and 6.8% of cases, respectively. Overall, the 5-year OS and 5-year DFS rates were 90.6% and 76.7%, respectively. At multivariable analysis, sex, age, pathological T stage and node ratio were significantly related to a better OS; age, histological type, pathological T stage and node ratio were related to DFS. These factors were used to generate the prognostic score, which showed statistically significant differences between the high-risk and low-risk groups: 5-year OS = 96.6% if score <3.1 vs 63.5% if score ≥3.1 [P < 0.0001; HR 17.56, 95% confidence interval (CI) 5.45-56.53]; 5-year DFS 92.3% if score <1.5 vs 52.5% if score ≥ 1.5 (P < 0.0001; HR 7.95, 95% CI 3.48-18.16).

CONCLUSIONS

The proposed prognostic scores seem to be effective in predicting outcomes for patients with LCs.

Diagnostic Value of Conventional PET Parameters and Radiomic Features Extracted from 18F-FDG-PET/CT for Histologic Subtype Classification and Characterization of Lung Neuroendocrine Neoplasms

Aim: To evaluate if conventional Positron emission tomography (PET) parameters and radiomic features (RFs) extracted by 18F-FDG-PET/CT can differentiate among different histological subtypes of lung neuroendocrine neoplasms (Lu-NENs). Methods: Forty-four naïve-treatment patients on whom 18F-FDG-PET/CT was performed for histologically confirmed Lu-NEN (n = 46) were retrospectively included. Manual segmentation was performed by two operators allowing for extraction of four conventional PET parameters (SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG)) and 41 RFs. Lu-NENs were classified into two groups: lung neuroendocrine tumors (Lu-NETs) vs. lung neuroendocrine carcinomas (Lu-NECs). Lu-NETs were classified according to histological subtypes (typical (TC)/atypical carcinoid (AC)), Ki67-level, and TNM staging. The least absolute shrink age and selection operator (LASSO) method was used to select the most predictive RFs for classification and Pearson correlation analysis was performed between conventional PET parameters and selected RFs. Results: PET parameters, in particular, SUVmax (area under the curve (AUC) = 0.91; cut-off = 5.16) were higher in Lu-NECs vs. Lu-NETs (p < 0.001). Among RFs, HISTO_Entropy_log10 was the most predictive (AUC = 0.90), but correlated with SUVmax/SUVmean (r = 0.95/r = 0.94, respectively). No statistical differences were found between conventional PET parameters and RFs (p > 0.05) and TC vs. AC classification. Conventional PET parameters were correlated with N+ status in Lu-NETs. Conclusion: In our study, conventional PET parameters were able to distinguish Lu-NECs from Lu-NETs, but not TC from AC. RFs did not provide additional information.

Prognostic significance of histopathological factors in survival and recurrence of atypical carcinoid tumours

OBJECTIVES

Atypical carcinoids are neuroendocrine neoplasms of intermediate degree and low frequency. The aim of this study is to analyse their clinical characteristics and the importance of different histopathological factors in their prognosis.

METHODS

Multicentre cooperative group EMETNE prospectively reviewed 153 patients operated on between 1998 and 2016 with diagnosis of atypical carcinoids. Clinical variables and histopathological features were assessed.

RESULTS

Mean age was 54.36 years, similar for both genders. Concerning pathological study, mean tumour size was 31.7 mm. Rosettes were presented in 17% of the cases and tumoural necrosis in 23.3%. The cell proliferation factor Ki-67 index was 10.7%. The 2- and 5-year overall survival rates were 95.8% and 88.9%, respectively. In the univariate study, statistically significant differences in survival were found for each of the categories of T, N and M factors. Mitotic index and quantification of expression of Ki-67 showed influence in overall survival, although without statistical significance. In the multivariate analysis, factors N, M and mitotic index behaved as independent prognostic factors related to survival. Median disease-free interval in the series was 163.35 months. In cases with loco-regional recurrence, 53% had positive hiliar or mediastinal nodal involvement at the time of the surgery. In the univariate analysis, we observed statistically significant differences in disease-free interval in patients with nodal involvement (P = 0.024) and non-anatomical resections (P = 0.04). Histological characteristics showed no statistically significant differences in disease-free interval.

CONCLUSIONS

Lymph node involvement, the development of distant metastasis and mitotic index, more than Ki-67 determination, were shown as independent prognostic factors related to survival of these patients.

Preoperative Biopsy Diagnosis in Pulmonary Carcinoids, a Shot in the Dark

INTRODUCTION

The preferred treatment for pulmonary carcinoids (PCs) is lobectomy, and parenchyma-sparing approaches might be considered for typical carcinoids (TCs). Treatment decisions are based on a preoperative biopsy diagnosis. Following the WHO criteria (2015), definitive diagnosis is only feasible postoperatively, thereby hampering preoperative treatment decisions. Here, we determined whether the final carcinoid classification on a resection specimen can be predicted by a preoperative biopsy.

METHODS

We searched all stage I to III patients with a final carcinoid diagnosis who underwent a curative resection and of whom both a preoperative biopsy and paired resection specimen were available (2003-2012) using the Dutch Pathology Registry (PALGA) and the Netherlands Cancer Registry (IKNL). Pathology report conclusions of the biopsy-resection specimen were compared.

RESULTS

Paired biopsy-resection specimens in combination with clinical data were available from 330 patients. 57% (189 of 330) of the patients exhibited discordance between the preoperative biopsy and paired resection diagnosis, including 36% (44 of 121) preoperatively diagnosed TC, 40% (six of 15) atypical carcinoid (AC), and 65% (103 of 158) not-otherwise-specified (NOS) carcinoids. A quarter of preoperatively diagnosed TC and NOS was reclassified as AC on the resection specimen. Preoperatively diagnosed ACs exhibited the highest relapse rates (40%, 6 of 15). Preoperatively diagnosed TC and NOS patients who were reclassified as ACs exhibited higher relapse rates as compared to nonreclassified TCs and NOS (3% versus 1%, and 16% versus 6%).

CONCLUSIONS

We provide evidence that carcinoid classification on preoperative biopsies is imprecise, as is also stated by the current WHO classification. We advise clinicians to interpret the preoperative biopsy diagnosis with caution in deciding the extent of surgery (e.g., parenchyma-sparing versus non-parenchyma-sparing).

Proposal of organ-specific subdivision of M component and staging system for metastatic pulmonary neuroendocrine tumor

OBJECTIVES

To evaluate the prognostic significance of patterns of distant metastatic organs in metastatic pulmonary neuroendocrine tumors (PNETs).

METHODS

891 metastatic PNETs patients (G1-typical carcinoid, 200; G2-atypical carcinoid, 68; G3-large-cell neuroendocrine carcinoma, 623) diagnosed between 2010 and 2016 were identified. Multivariate analysis was performed using a Cox regression model to identify prognostic factors associated with cancer-specific survival (CSS). The novel M component was established based on the hazard ratio of different metastatic organs. A disease-specific staging system was then proposed by using k-means cluster analysis.

RESULTS

For metastatic PNETs, involvement of bone, liver or brain and multiple metastatic organs were identified as independent prognostic factors in multivariate analysis. M categories was subdivided into three subcategories: M1a, lung involvement only or distant lymph node involvement only; M1b, bone involvement only or liver involvement only; M1c, brain involvement regardless of number of metastatic organs or multiple organs involvement except brain. Primary site surgery, chemotherapy and histologic subtypes were independently associated with CSS, but T component and N component were not. After regrouping histologic subtypes and novel M component, we proposed the following modified staging system: stage IVA (G1M1any, G2M1a-b), stage IVB (G2M1c, G3M1a-b) and stage IVC (G3M1c). The 2-year CSS were 77.9 %, 16.4 % and 5.3 %.

CONCLUSIONS

Subdivision of M component according to patterns of distant metastatic organs facilitates prognostic significance for PNETs. Brain metastases and multiple metastatic organs were associated with significantly inferior prognosis. Incorporating histologic subtypes and novel M categories create a disease-specific staging system showed good discriminatory capacity.

NEP-Score Thresholds Predict Survival of Patients With Bronchial Carcinoids

Survival prognostic markers are extremely needed to better define therapeutic strategies in patients with bronchial carcinoids (BC). We aim to verify the applicability of the NEP-Score in a homogeneous BC cohort and identify a derivative prognostic marker, the NEP-Score at diagnosis (NEP-D) that does not consider new metastases during follow-up. Sixty-four patients (38 females, and 26 males, mean age at diagnosis 58.9 ± 1.7 years) with BC were retrospectively evaluated. NEP-Score was calculated at the end of follow-up (NEP-T). A derivative score, the NEP-Score at diagnosis (NEP-D) that does not consider new metastases during follow-up, was then assessed. Patients were subdivided according to their living status at the end of follow-up. A NEP-Score threshold was investigated to predict survival. Mean NEP-T and mean NEP-D were significantly lower in live patients at end of follow-up. A NEP-T cut-off >138 significantly predicts survival. Atypical BC relapsed more frequently than Typical BC. Male gender and previous malignancy were negative prognostic factors for survival. We confirmed NEP-Score applicability in BC and NEP-D utility, being the latter a simple, quick, and cheap prognostic score that can help clinicians in decision making. The identified NEP-D threshold can predict NEN aggressiveness and may be used to define the best personalized therapeutic strategy. In this context, a validation study is needed.

Staging System for Neuroendocrine Tumors of the Lung Needs to Incorporate Histologic Grade

BACKGROUND

Neuroendocrine tumors of the lung are staged with the American Joint Committee on Cancer (AJCC) TNM system for non-small cell lung cancer. However neuroendocrine tumors have a distinct clinical behavior with grade providing critical prognostic information. We aim to determine components of a tumor-specific staging system.

METHODS

We identified 12,415 of 58,736 neuroendocrine patients with complete 8th edition AJCC staging information in the National Cancer Database from 2004 to 2014. Data were randomized into training (n = 8324) and validation (n = 4091) sets and analyzed separately. Recursive partitioning followed by Cox regression was performed to classify by grade (G1, typical carcinoid; G2, atypical carcinoid; G3, large cell neuroendocrine), T category, and nodal status. Overall survival according to individual grade and an integrated grade-specific staging was compared by Kaplan-Meier analysis.

RESULTS

Overall 7524 G1, 1211 G2, and 3680 G3 tumors were analyzed with no differences between sets. Each grade was separately classified by the AJCC TNM system with poor separation of the curves and clustered survival. Recursive partitioning identified grade as the most significant factor driving overall survival. Subsequent partitions identified nodal status and then T category as additional important factors, consistent with results from the Cox regression analysis (G2 hazard ratio, 3.05 [95% confidence interval, 2.65-3.5]; G3 hazard ratio, 9.03 [95% confidence interval, 8.22-9.92]). When grade was integrated with nodal status and T category to approximate a tumor-specific staging system, distinct overall survival stratification occurred at each proposed stage.

CONCLUSIONS

Grade was the dominant driver of prognosis in patients with neuroendocrine tumors of the lung. Incorporation of grade with traditional TNM parameters better discriminates between stage categories compared with current AJCC staging. Future staging systems for neuroendocrine tumors of the lung should include histologic grade.

Prognostic nomogram predicts overall survival in pulmonary large cell neuroendocrine carcinoma

BACKGROUND

Large cell neuroendocrine carcinoma (LCNEC) is a rare and typically aggressive malignancy with poor prognosis. This study developed a nomogram model to predict the overall survival (OS) of patients with LCNEC.

METHODS

LCNEC patients were identified from the Surveillance, Epidemiology, and End Results database between 2004-2014. Univariate and multivariate Cox regression models were used to determine demographic and clinicopathological features associated with OS. A nomogram model was generated to predict OS and its performance was assessed by Harrell's concordance index (C-index), calibration plots, and subgroup analysis by risk scores.

RESULTS

Of 3048 eligible patients with LCNEC, 2138 were randomly grouped into the training set and 910 into the validation set. Age at diagnosis, gender, tumor stage, N stage, tumor size, and surgery of primary site were independent prognostic factors of OS. C-index values of the nomogram were 0.75 (95% CI, 0.74-0.76) and 0.76 (95% CI, 0.74-0.77) in the training and validation sets, respectively. In both cohorts, the calibration plots showed good concordance between the predicted and observed OS at 3 and 5 years. Kaplan-Meier curves revealed significant differences in OS in patients stratified by nomogram-based risk score, and patients with a higher-than-median risk score had poorer OS.

CONCLUSION

This is the first nomogram developed and validated in a large population-based cohort for predicting OS in patients with LCNEC, and it shows favorable discrimination and calibration abilities. Use of this proposed nomogram has the potential to improve prediction of survival risk, and lead to individualized clinical decisions for LCNEC.

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.