Staging lymph node metastases from lung cancer in the mediastinum

Developing a primary tumor and lymph node 18F-FDG PET/CT-clinical (TLPC) model to predict lymph node metastasis of resectable T2-4 NSCLC

PURPOSE

The goal of this study was to investigate whether the combined PET/CT radiomic features of the primary tumor and lymph node could predict lymph node metastasis (LNM) of resectable non-small cell lung cancer (NSCLC) in stage T2-4.

METHODS

This retrospective study included 192 NSCLC patients who underwent tumor and node dissection between August 2016 and December 2017 and underwent ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT scanning 1-3 weeks before surgery. In total, 192 primary tumors (> 3 cm) and 462 lymph nodes (LN > 0.5 cm) were analyzed. The pretreatment clinical features of these patients were recorded, and the radiomic features of their primary tumor and lymph node were extracted from PET/CT imaging. The Spearman's relevance combined with the least absolute shrinkage and selection operator was used for radiomic feature selection. Five independent machine learning models (multi-layer perceptron, extreme Gradient Boosting, light gradient boosting machine, gradient boosting decision tree, and support vector machine) were tested as classifiers for model development. We developed the following three models to predict LNM: tumor PET/CT-clinical (TPC), lymph PET/CT-clinical (LPC), and tumor and lymph PET/CT-clinical (TLPC). The performance of the models and the clinical node (cN) staging was evaluated using the ROC curve and confusion matrix analysis.

RESULTS

The ROC analysis showed that among the three models, the TLPC model had better predictive clinical utility and efficiency in predicting LNM of NSCLC (AUC = 0.93, accuracy = 85%; sensitivity = 0.93; specificity = 0.75) than both the TPC model (AUC = 0.54, accuracy = 50%; specificity = 0.38; sensitivity = 0.59) and the LPC model (AUC = 0.82, accuracy = 70%; specificity = 0.41; sensitivity = 0.92). The TLPC model also exhibited great potential in predicting the N2 stage in NSCLC (AUC = 0.94, accuracy = 79%; specificity = 0.64; sensitivity = 0.91).

CONCLUSION

The combination of CT and PET radiomic features of the primary tumor and lymph node showed great potential for predicting LNM of resectable T2-4 NSCLC. The TLPC model can non-invasively predict lymph node metastasis in NSCLC, which may be helpful for clinicians to develop more rational therapeutic strategies.

Infiltration of metastatic lymph nodes with PD-1+ T cells is associated with improved disease-free and overall survival in resected N+ NSCLC

Tumor metastases to regional lymph nodes are associated with worse outcome for patients with resected non-small cell lung cancer (NSCLC), but there is a wide variation in survival. We hypothesized that infiltration of tumor-involved lymph nodes with activated effector T cells would impact subsequent outcome. A total of 54 lymph nodes (27 N⁺ and 15 N^- collected from 12 patients with Stage IIB (T₂N₁M₀) and 12 N^- lymph nodes collected from 10 patients with Stage IIA (T₂N₀M₀) who underwent lymphadenectomy during surgical management of their NSCLC) were analyzed for effector T cells expressing activation markers PD-1 and TIM-3 using the Opal-multiple immunofluorescence assay. The frequency of CD3⁺CD8⁺ (P=0.0001), CD3⁺CD8⁺TIM-3⁺ (P<0.0001), and CD3⁺CD8⁺TIM-3⁺Ki-67⁺ (P<0.0001) T cells was greater in lymph nodes of IIA patients compared with IIB patients; however the frequency of CD3⁺CD8⁺PD-1⁺ (P=0.0086), CD3⁺CD8⁺TIM-3⁺ (P=0.0129), CD3⁺CD8⁺PD-1⁺Ki-67⁺ (P<0.0001) and CD3⁺CD8⁺TIM-3⁺Ki-67⁺ (P=0.0001) T cells was greater among the tumor involved (N⁺) nodes of N1 patients compared with the tumor-uninvolved (N^-) nodes. The frequency of intranodal CD3⁺CD8⁺, CD3⁺CD8⁺PD-1⁺ and CD3⁺CD8⁺PD-1⁺Ki-67⁺ T cells in N⁺ nodes was associated with prolonged progression-free (PFS) and overall survival (OS). These data suggest that CD3⁺CD8⁺TIM-3⁺ T cells may suppress tumor spread to regional lymph nodes but once tumor cells metastasize to lymph nodes, CD3⁺/CD8⁺/PD-1⁺/Ki67⁺ T cells localizing to N⁺ nodes may prevent further tumor spread, resulting in prolonged survival.

Cox regression with survival-time-dependent missing covariate values

Analysis with time-to-event data in clinical and epidemiological studies often encounters missing covariate values, and the missing at random assumption is commonly adopted, which assumes that missingness depends on the observed data, including the observed outcome which is the minimum of survival and censoring time. However, it is conceivable that in certain settings, missingness of covariate values is related to the survival time but not to the censoring time. This is especially so when covariate missingness is related to an unmeasured variable affected by the patient's illness and prognosis factors at baseline. If this is the case, then the covariate missingness is not at random as the survival time is censored, and it creates a challenge in data analysis. In this article, we propose an approach to deal with such survival-time-dependent covariate missingness based on the well known Cox proportional hazard model. Our method is based on inverse propensity weighting with the propensity estimated by nonparametric kernel regression. Our estimators are consistent and asymptotically normal, and their finite-sample performance is examined through simulation. An application to a real-data example is included for illustration.

PET-CT has low specificity for mediastinal staging of non-small-cell lung cancer in an endemic area for tuberculosis: a diagnostic test study (LACOG 0114)

Background

The present study aims to assess the performance of 18F-FDG PET-CT on mediastinal staging of non-small cell lung cancer (NSCLC) in a location with endemic granulomatous infectious disease.

Methods

Diagnostic test study including patients aged 18 years or older with operable stage I-III NSCLC and indication for a mediastinal lymph node biopsy. All patients underwent a 18F-FDG PET-scan before invasive mediastinal staging, either through mediastinoscopy or thoracotomy, which was considered the gold-standard. Surgeons and pathologists were blinded for scan results. Primary endpoint was to evaluate sensitivity, specificity and positive and negative predictive values of PET-CT with images acquired in the 1st hour of the exam protocol, using predefined cutoffs of maximal SUV, on per-patient basis.

Results

Overall, 85 patients with operable NSCLC underwent PET-CT scan followed by invasive mediastinal staging. Mean age was 65 years, 49 patients were male and 68 were white. One patient presented with active tuberculosis and none had HIV infection. Using any SUV_max > 0 as qualitative criteria for positivity, sensitivity and specificity were 0.87 and 0.45, respectively. Nevertheless, even when the highest SUV cut-off was used (SUV_max ≥5), specificity remained low (0.79), with an estimated positive predictive value of 54%.

Conclusions

Our findings are in line with the most recent publications and guidelines, which recommend that PET-CT must not be solely used as a tool to mediastinal staging, even in a region with high burden of tuberculosis.

Trial registration

The LACOG 0114 study was registered at ClinicalTrials.gov, before study initiation, under identifier NCT02664792.

Surgical experience and patient-related restrictions predict the adequacy of cervical mediastinoscopy in non-small cell lung carcinoma lymph node staging

BACKGROUND

Until recently, cervical mediastinoscopy was considered to be the reference standard for mediastinal staging for Non-Small Cell Lung Carcinoma (NSCLC). In the absence of metastases, mediastinal lymph node involvement is the most important prognostic factor and as such it determines therapeutic strategies. In this study we evaluated the adequacy of cervical mediastinoscopy in NSCLC lymph node staging in a large university hospital over more than a decade. In addition, we determined the influence of: (1) surgeon's experience (2) video-assisted mediastinoscopy (VAM) and (3) patient-related restrictions (PRR) on the adequacy of lymph node sampling.

METHODS

Between January 2001 and December 2014, 225 patients underwent cervical mediastinoscopy for lymph node staging. Surgical and histological data were reviewed. Thirty-day follow-up was available for all patients. Lymph node sampling was considered adequate when stations 4 L, 4R and 7 were sampled (ESTS guidelines). A surgeon was considered to be experienced when he or she performed at least 40 procedures during the study-period.

RESULTS

Intraoperative mortality was 0%. Thirty-day mortality was 1.3%. Overall adequacy of lymph node sampling was 56%. Univariate and multivariate logistic regression analyses of lymph node sampling adequacy revealed level of surgical experience and PRR as independent predictors of lymph node sampling adequacy.

CONCLUSIONS

Surgical experience and PRR independently predict the adequacy of cervical mediastinoscopy in NSCLC lymph node staging. VAM does not independently predict the adequacy of mediastinal lymph node sampling. In light of the expected further decline in mediastinoscopy numbers, we recommend to limit this procedure exclusively to the armamentarium of the experienced thoracic surgeon.

Five-year survival analysis and prognostic factors in patients operated on for non-small cell lung cancer with N2 disease

Background

The aim of the study is to analyse 5-year survival and prognostic factors in patients operated due to lung cancer with postoperatively confirmed metastases to N2 group nodes.

Methods

In the years 2007-2015, 1,148 patients with lung cancer were treated surgically. A postoperative histopathological study confirmed N2 feature in 150 patients. One hundred and ten patients, in whom a 5-year survival analysis was possible to perform, were included in such analysis. The patients underwent the following procedures: pneumonectomy, 31 patients; lobectomy, 61; bilobectomy, 10; and wedge resection, 8. All patients were subjected to supplementary treatment after the surgery.

Results

Five-year survival was achieved in 23 patients (21%). The patients' survival did not depend on the type of surgery, type of tumour, its location or presence of metastases in N1 nodes (P=0.82, P=0.51, P=0.36 and P=0.23, respectively). A statistically significant correlation was observed (P=0.01) between the 5-year survival of a patient and the occurrence of metastases only in one group of lymph nodes of the N2 feature (22 patients, 20%). Involvement of three or more mediastinal nodal groups resulted in survival shorter than 5-year.

Conclusions

(I) In patients with the N2 feature, the type of performed surgery, type of tumour and the occurrence of metastases in the lymph nodes of the lung hilum do not affect 5-year survival; (II) involvement of only one nodal group allows to achieve 5-year survival in 20% of patients; (III) involvement of three and more nodal groups with the N2 feature results in decreased 5-year survival.

18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)-Radiomics of metastatic lymph nodes and primary tumor in non-small cell lung cancer (NSCLC) - A prospective externally validated study

BACKGROUND

Lymph node stage prior to treatment is strongly related to disease progression and poor prognosis in non-small cell lung cancer (NSCLC). However, few studies have investigated metabolic imaging features derived from pre-radiotherapy 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) of metastatic hilar/mediastinal lymph nodes (LNs). We hypothesized that these would provide complementary prognostic information to FDG-PET descriptors to only the primary tumor (tumor).

METHODS

Two independent cohorts of 262 and 50 node-positive NSCLC patients were used for model development and validation. Image features (i.e. Radiomics) including shape and size, first order statistics, texture, and intensity-volume histograms (IVH) (http://www.radiomics.io/) were evaluated by univariable Cox regression on the development cohort. Prognostic modeling was conducted with a 10-fold cross-validated least absolute shrinkage and selection operator (LASSO), automatically selecting amongst FDG-PET-Radiomics descriptors from (1) tumor, (2) LNs or (3) both structures. Performance was assessed with the concordance-index. Development data are publicly available at www.cancerdata.org and Dryad (doi:10.5061/dryad.752153b).

RESULTS

Common SUV descriptors (maximum, peak, and mean) were significantly related to overall survival when extracted from LNs, as were LN volume and tumor load (summed tumor and LNs' volumes), though this was not true for either SUV metrics or tumor's volume. Feature selection exclusively from imaging information based on FDG-PET-Radiomics, exhibited performances of (1) 0.53 -external 0.54, when derived from the tumor, (2) 0.62 -external 0.56 from LNs, and (3) 0.62 -external 0.59 from both structures, including at least one feature from each sub-category, except IVH.

CONCLUSION

Combining imaging information based on FDG-PET-Radiomics features from tumors and LNs is desirable to achieve a higher prognostic discriminative power for NSCLC.

FDG-PET parameters predicting mediastinal malignancy in lung cancer

Background

Staging of mediastinal lymph nodes in non-small cell lung cancer (NSCLC) is mandatory. The maximum Standard Uptake Value (SUVmax) obtained using F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is the best non-invasive technique available for this evaluation, but its performance varies from center to center. The aim of the present study was to identify FDG-PET predictors of mediastinal malignancy that are able to minimize intercenter variability and improve the selection of subsequent staging procedures.

Method

A multicenter study of NSCLC patients staged through FDG-PET and endobronchial ultrasonography with needle aspiration (EBUS-NA) was performed using therapeutic surgery with systematic nodal dissection as gold standard. Intercenter variability and predictive power for mediastinal malignancy of different FDG-PET measures were assessed, as well as the role of these measures for selecting additional staging procedures.

Results

One hundred and twenty-one NSCLC patients, of whom 94 (72%) had ≥1 hypermetabolic spots in the mediastinum, were included in the study. Mean SUVmax of the primary tumor was 12.3 (SD 6.3), and median SUVmax of the highest hypermetabolic spots in the mediastinum was 3.9 (IQR 2.4-7). Variability of FDG-PET measures between hospitals was statistically significant (p = 0.016 and p < 0.001 respectively), but lost significance when SUVmax in the mediastinum was expressed as a ratio or a subtraction from the primary tumor (SUVmax mediastinum/tumor, p = 0.083; and SUVmax mediastinum - tumor, p = 0.428 respectively). SUVmax mediastinum/tumor showed higher accuracy in the ROC analysis (AUC 0.77 CI 0.68-0.85, p < 0.001), and showed predictive power for mediastinal malignancy when using a 0.4 cutoff (OR 6.62, 95%CI 2.98-14.69). Sensitivities and negative predictive values of clinical staging through EBUS-NA attained values ranging between 57% and 92% after FDG-PET, which improved with additional techniques when the tumor had a diameter >3 cm and/or a SUVmax mediastinum/tumor ratio >0.4.

Conclusion

The SUVmax mediastinum/tumor ratio is a good predictor of regional tumor extension in NSCLC. This measure is not influenced by intercenter variability and has an accuracy of over 70% for the identification of malignancy when using a 0.4 cutoff.

Mediastinal lymph node detection and station mapping on chest CT using spatial priors and random forest

PURPOSE

To develop an automated system for mediastinal lymph node detection and station mapping for chest CT.

METHODS

The contextual organs, trachea, lungs, and spine are first automatically identified to locate the region of interest (ROI) (mediastinum). The authors employ shape features derived from Hessian analysis, local object scale, and circular transformation that are computed per voxel in the ROI. Eight more anatomical structures are simultaneously segmented by multiatlas label fusion. Spatial priors are defined as the relative multidimensional distance vectors corresponding to each structure. Intensity, shape, and spatial prior features are integrated and parsed by a random forest classifier for lymph node detection. The detected candidates are then segmented by the following curve evolution process. Texture features are computed on the segmented lymph nodes and a support vector machine committee is used for final classification. For lymph node station labeling, based on the segmentation results of the above anatomical structures, the textual definitions of mediastinal lymph node map according to the International Association for the Study of Lung Cancer are converted into patient-specific color-coded CT image, where the lymph node station can be automatically assigned for each detected node.

RESULTS

The chest CT volumes from 70 patients with 316 enlarged mediastinal lymph nodes are used for validation. For lymph node detection, their system achieves 88% sensitivity at eight false positives per patient. For lymph node station labeling, 84.5% of lymph nodes are correctly assigned to their stations.

CONCLUSIONS

Multiple-channel shape, intensity, and spatial prior features aggregated by a random forest classifier improve mediastinal lymph node detection on chest CT. Using the location information of segmented anatomic structures from the multiatlas formulation enables accurate identification of lymph node stations.

Evaluation of Mediastinal Lymph Nodes in Sarcoidosis, Sarcoid Reaction, and Malignant Lymph Nodes Using CT and FDG-PET/CT

The aim of this study was to analyze the clinical, computed tomography (CT), and positron emission tomography (PET) findings of sarcoidosis, sarcoid reaction, and malignant lymph nodes (LNs) to the results of transbronchial LN aspiration and biopsy (TBNA).The TBNA results of mediastinal and hilar LNs of 152 patients in our hospital from July 2008 to March 2013 were retrospectively reviewed. Two independent radiologists measured the size and attenuation of LNs on CT and assessed the probability of the 3 categories: sarcoidosis (n = 36), sarcoid reaction (n = 25), or malignant LNs (n = 91). The total volume and attenuation of LNs were measured using Image J (NIH). The median maximum standardized uptake value (maxSUV) of the 3 mediastinal and hilar LNs on PET/CT was obtained.There was no significantly different CT finding between sarcoidosis and sarcoid reaction. Multivariate analysis showed that the age, total volume of LNs, and number of enlarged LNs significantly differed between sarcoid reaction and malignant LNs. Sarcoid reaction tends to be occurred in young patients (P = 0.007), the total volume of LNs was smaller (P = 0.04) than that of malignant LNs, and there were significantly more LNs >1 cm (P = 0.005). The median maxSUV of the 3 highest SUVs of the LNs did not significantly differ between the 3 entities.

Usefulness of positron emission tomography-computed tomography in pre-operative evaluation of intra-thoracic esophageal cancer

Background

The purpose of the study was to clarify the usefulness of positron emission tomography-computed tomography (PET-CT) for pre-operative evaluation of intra-thoracic esophageal cancer, especially in terms of regional lymph node status.

Methods

Medical records of 93 consecutive cases from July 2007 to October 2012 were retrospectively reviewed. All patients underwent curative and complete esophagectomies for intra-thoracic esophageal cancer. We compared pre-operative maximum standard uptake values (SUVmax) of esophageal tumors and regional lymph nodes (LN) with other variables (chronic obstructive pulmonary disease, history of previous other primary cancer, gender, differentiation, and neoadjuvant therapy). In addition, the SUVmax of tumors and LNs were analyzed with pathologic findings.

Results

There was no significant difference of each tumor and LN SUVmax according to factors including chronic lung disease, age, history of previous other cancer, differentiation, and gender. Pre-operative evaluations by PET-CT were not accurate (tumor sensitivity 76.4%, specificity 25%; LN sensitivity 45.2%, specificity 54.8%). Receiver operating characteristic analysis showed that LN metastasis could not be appropriately diagnosed with SUVmax (P = 0.871). There was no difference in SUVmax between pathologically positive and negative LN subgroups. Tumor SUVmax correlated with the progression of esophageal cancer in patients without neoadjuvant therapy (P < 0.001). However, LN SUVmax had no correlation with overall pathologic stage. After neoadjuvant therapy, there were significant decreases in SUVmax in both pathologically positive and negative LN subgroups (P = 0.043, P = 0.008).

Conclusion

 Surgery should not be withheld in N-stage according to PET-CT findings and carefully considered in conjunction with other conditions.

Concurrent chemoradiotherapy with vinorelbine plus split-dose cisplatin may be an option in inoperable stage III non-small cell lung cancer: a single-center experience

BACKGROUND

Concurrent chemoradiotherapy is the current standard treatment for inoperable stage III non-small cell lung cancer (NSCLC). In this study we aimed to investigate the efficacy and toxicity of CCRT with split dose of cisplatin (30 mg/m2) and vinorelbine (20 mg/m2) in patients with inoperable stage III NSCLC followed in our oncology clinic.

MATERIAL AND METHODS

Medical records of 97 patients with inoperable stage III NSCLC treated with concurrent chemoradiotherapy with cisplatin-vinorelbine were retrospectively analyzed. Cisplatin (30 mg/m2) and vinorelbine (20 mg/m2) were administered on days 1, 8, 22, and 29 during radiotherapy. Two cycles of consolidation chemotherapy were given. All patient data, including pathological, clinical, radiological, biochemical, and hematological data, were assessed retrospectively using our database system.

RESULTS

Our study included 97 unresectable stage III NSCLC patients who were treated with CCRT. Median age was 58 years old (range 39-75) and 87 (89.7%) of the patients were men. ECOG performance score was 0-1 in 93 patients (95.9%). Squamous histology, the most common histology, was diagnosed in 46 patients (47.4%). Median follow-up time was 23.8 months. Median progression-free survival (PFS) and median overall survival time (OS) were 10.3 months and 17.8 months, respectively. Objective response rate and clinical benefit rate were 75.3% and 83.5%, respectively. Distant and local relapse rate were 57.1% and 42.9%, respectively. Hematological and non-hematological grade 3-4 toxicities were seen in 13 (13.4%) and 16 (16.5%) patients, respectively. Six (6.1%) patients died due to toxicity.

CONCLUSIONS

The results of this study suggest that split-dose cisplatin may offer fewer grade III-IV toxicities without sacrificing efficacy and could be an option in patients with inoperable stage III NSCLC during CCRT. Similar to past studies, despite high response rate during CCRT, distant relapse is the major parameter that influences patient survival in long-term in NSCLC.