Clinical Characteristics of False-Positive Lymph Node on Chest CT or PET-CT Confirmed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in Lung Cancer

The value of net influx constant based on FDG PET/CT dynamic imaging in the differential diagnosis of metastatic from non-metastatic lymph nodes in lung cancer

OBJECTIVES

This study aims to evaluate the value of the dynamic and static quantitative metabolic parameters derived from 18F-fluorodeoxyglucose (FDG)-positron emission tomography/CT (PET/CT) in the differential diagnosis of metastatic from non-metastatic lymph nodes (LNs) in lung cancer and to validate them based on the results of a previous study.

METHODS

One hundred and twenty-one patients with lung nodules or masses detected on chest CT scan underwent 18F-FDG PET/CT dynamic + static imaging with informed consent. A retrospective collection of 126 LNs in 37 patients with lung cancer was pathologically confirmed. Static image analysis parameters include LN-SUVmax and LN-SUVmax/primary tumor SUVmax (LN-SUVmax/PT-SUVmax). Dynamic metabolic parameters including the net influx rate (Ki) and the surrogate of perfusion (K1) and of each LN were obtained by applying the irreversible two-tissue compartment model using in-house Matlab software. Ki/K1 was then calculated as a separate marker. Based on the pathological findings, we divided into a metastatic group and a non-metastatic group. The χ2 test was used to evaluate the agreement of the individual and combined diagnosis of each metabolic parameter with the gold standard. The receiver-operating characteristic (ROC) analysis was performed for each parameter to determine the diagnostic efficacy in differentiating non-metastatic from metastatic LNs with high FDG-avid. P < 0.05 was considered statistically significant.

RESULTS

Among the 126 FDG-avid LNs confirmed by pathology, 70 LNs were metastatic, and 56 LNs were non-metastatic. For ROC analysis, in separate assays, the dynamic metabolic parameter Ki [sensitivity (SEN) of 84.30%, specificity (SPE) of 94.60%, accuracy of 88.89%, and AUC of 0.895] had a better diagnostic value than the static metabolic parameter SUVmax (SEN of 82.90%, SPE of 62.50%, accuracy of 74.60%, and AUC of 0.727) in differentiating between metastatic from non-metastatic LNs groups, respectively. In the combined diagnosis group, the combined SUVmax + Ki diagnosis had a better diagnostic value in the differential diagnosis of metastatic from non-metastatic LNs, with SEN, SPE, accuracy, and AUC of 84.3%, 94.6%, 88.89%, and 0.907, respectively.

CONCLUSIONS

When the cutoff value of Ki was 0.022 ml/g/min, it had a high diagnostic value in the differential diagnosis between metastasis and non-metastasis in FDG-avid LNs of lung cancer, especially in improving the specificity. The combination of SUVmax and Ki is expected to be a reliable metabolic parameter for N-staging of lung cancer.

The burden of tuberculosis among patients with non-small cell lung carcinoma in a tertiary care center

BACKGROUND

Lung cancer and tuberculosis share similar risk factors, clinical spectrum, radiological features and it is difficult to differentiate but it is important to diagnose both conditions for targeted therapy and better outcome.

AIMS

Our primary objective was to estimate the proportion of TB in primary biopsy proven non-small cell lung carcinoma (NSCLC) cases.

MATERIAL & METHODS

This prospective observational study was conducted in the Departments of Medicine/Pulmonary Medicine/Medical Oncology and Microbiology at the All India Institute of Medical Sciences, New Delhi for a period of 2 years (January 2020-December 2021). Patients with biopsy proven, primary non-small cell lung cancer were recruited and sputum samples were subjected to microbiological investigations to confirm tuberculosis. Comparison was done in two groups of lung cancer patients with confirmed TB (Group A) and without confirmed tuberculosis (Group B).

RESULTS

Total 75 patients with biopsy proven, primary NSCLC were recruited and 16 % (12/75) were diagnosed with confirmed TB. Adenocarcinoma (36.48 %) and Squamous cell carcinoma (33.44 %) were the two predominant histopathological subtypes of NSCLC. About 57 (76 %) of them were found to be in stage IV of Lung cancer at initial presentation itself (75 % in group A & 74.6 % in group B; p value < 0.80). A majority of patients (11/12 cases; 91 %) of group A were males with a mean age of 59 ± 7.5 years. The upper lobes of the lung were involved in 65 % (49/75) of the cases and showing a mass lesion on imaging (75 % in group A & 65 % in group B; p value < 0.52). Kaplan Meier survival revealed a median survival time of 11 months in subjects with only NSCLC and a median survival time of 4 months in the group with concomitant TB and NSCLC (p value < 0.44).

Fibroblast Activation Protein-Directed Imaging Outperforms 18F-FDG PET/CT in Malignant Mesothelioma: A Prospective, Single-Center, Observational Trial

The fibroblast activation protein (FAP) is highly expressed in tumor and stromal cells of mesothelioma and thus is an interesting imaging and therapeutic target. Previous data on PET imaging with radiolabeled FAP inhibitors (FAPIs) suggest high potential for superior tumor detection. Here, we report the data of a large malignant pleural mesothelioma cohort within a 68Ga-FAPI46 PET observational trial (NCT04571086). Methods: Of 43 eligible patients with suspected or proven malignant mesothelioma, 41 could be included in the data analysis of the 68Ga-FAPI46 PET observational trial. All patients underwent 68Ga-FAPI46 PET/CT, contrast-enhanced CT, and 18F-FDG PET/CT. The primary study endpoint was the association of 68Ga-FAPI46 PET uptake intensity and histopathologic FAP expression. Furthermore, secondary endpoints were detection rate and sensitivity, specificity, and positive and negative predictive values as compared with 18F-FDG PET/CT. Datasets were interpreted by 2 masked readers. Results: The primary endpoint was met, and the association between 68Ga-FAPI46 SUVmax or SUVpeak and histopathologic FAP expression was significant (SUVmax: r = 0.49, P = 0.037; SUVpeak: r = 0.51, P = 0.030).68Ga-FAPI46 and 18F-FDG showed similar sensitivity by histopathologic validation on a per-patient (100.0% vs. 97.3%) and per region (98.0% vs. 95.9%) basis. Per-region analysis revealed higher 68Ga-FAPI46 than 18F-FDG specificity (81.1% vs. 36.8%) and positive predictive value (87.5% vs. 66.2%). Conclusion: We confirm an association of 68Ga-FAPI46 uptake and histopathologic FAP expression in mesothelioma patients. Additionally, we report high sensitivity and superior specificity and positive predictive value for 68Ga-FAPI46 versus 18F-FDG.

False-positive supraclavicular lymph node detected on chest computed tomography in oncology patients: Clinical implication based on subsequent neck ultrasonography and ultrasonography-guided tissue sampling

PURPOSE

The purpose of this study was to assess the prevalence and clinical implications of false-positive supraclavicular lymph node (LN) detected on chest computed tomography (CT), using subsequent neck ultrasonography (US) and US-guided tissue sampling.

METHODS

Among 172 patients with suspected supraclavicular LNs identified on CT, 87 underwent neck US or US-guided tissue sampling. Receiver operating characteristic curve and logistic regression analyses were performed to determine the diagnostic performance of US and independent predictors of false-positive LNs.

RESULTS

Among 87 patients, 49 (56.3%) were pathologically confirmed as metastases, 26 (29.9%) were negative for malignancy, and 12 (13.8%) had pseudolesions or schwannomas. The diagnostic indices were as follows: sensitivity, 91.8%; specificity, 92.3%; PPV, 95.7%; NPV, 85.7%; and accuracy, 92.0% (AUC = 0.921; 95% CI: 0.832-0.970, p < 0.001). The false-positive group had a higher mean age than the true-positive group (mean age, 69.8 ± 9.2 vs. 63.9 ± 9.8, p = 0.003). Logistic regression analyses revealed that age ≥ 65 years was the only independent predictor of false-positive LNs (OR = 4.391; 95% CI: 1.037-18.582; p = 0.044).

CONCLUSION

Subsequent US can be helpful for evaluating suspicious supraclavicular LNs detected on CT to establish appropriate management, especially in older patients.

Evaluation of hypermetabolic mediastinal-hilar lymph nodes determined by PET/CT with EBUS-TBNA and calculation of SUVmax cutoff values in differentiation of malignancy

Computed tomography (CT) and positron emission tomography (PET) are the most commonly used methods for diagnosis and staging in both malignant and benign diseases of the lung parenchyma and mediastinum. Endobronchial ultrasonography (EBUS) guided transbronchial needle aspiration biopsy (TBNA) has become widespread in recent years because it allows minimally invasive tissue sampling. PET-CT has high sensitivity in the diagnosis of malignancy but has low specificity. The false positive rate is high with the SUVmax 2.5 cutoff value, which is widely used in studies about malignancy. In our study, we evaluated lymph nodes with high F18-fluorodeoxyglucose (FDG) uptake on PET/CT and sampled by EBUS-TBNA. We aimed to calculate the new SUVmax cutoff values in the differentiation of malignancy. Our study included 103 patients who were examined for any reason and who underwent biopsy with EBUS-TBNA due to mediastinal or hilar lymph node enlargement on PET-CT. The relationship between PET-CT findings and EBUS findings, EBUS-TBNA results was evaluated. Biopsies were taken from 140 lymph nodes in 103 patients included in our study, and 39 (27.8%) were diagnosed as malignant. In our study, when the SUVmax cutoff value in PET-CT is taken as 2.54, the sensitivity is 98%, but the specificity remains at the level of 12%. When the SUVmax cutoff value in PET-CT was taken as 4.58, the sensitivity was 92% and the specificity was 49%. When this value was accepted as 5.25, and 6.09 the sensitivity was respectively 90% and 85%, the specificity was respectively 52% and 60%. In evaluations, we conducted in order to determine different SUVmax cutoff values that can be used for higher sensitivity and specificity in malignancy studies, the cutoff values were 4.58, 5.25, and 6.09. It is thought that these cutoff values will be useful both for diagnosing malignancy and for distinguishing benign pathologies.

Histology of the Primary Tumor Correlates with False Positivity of Integrated 18F-FDG-PET/CT Lymph Node Staging in Resectable Lung Cancer Patients

This study aimed to evaluate the diagnostic accuracy and false positivity rate of lymph node (LN) staging assessed by integrated 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG-PET/CT) in patients with operable lung cancer to the tumor histology. In total, 129 consecutive patients with non-small-cell lung cancer (NSCLC) undergoing anatomical lung resections were included. Preoperative LN staging was evaluated in the relationship to the histology of the resected specimens (group 1: lung adenocarcinoma/LUAD; group 2: squamous cell carcinoma/SQCA). Statistical analysis was performed by the Mann-Whitney U-test, the chi² test, and binary logistic regression analysis. To establish an easy-to-use algorithm for the identification of LN false positivity, a decision tree including clinically meaningful parameters was generated. In total, 77 (59.7%) and 52 (40.3%) patients were included in the LUAD and SQCA groups, respectively. SQCA histology, non-G1 tumors, and tumor SUVmax > 12.65 were identified as independent predictors of LN false positivity in the preoperative staging. The corresponding ORs and their 95% CIs were 3.35 [1.10-10.22], p = 0.0339; 4.60 [1.06-19.94], p = 0.0412; and 2.76 [1.01-7.55], and p = 0.0483. The preoperative identification of false-positive LNs is an important aspect of the treatment regimen for patients with operable lung cancer; thus, these preliminary findings should be further evaluated in larger patient cohorts.

Assessment of intrathoracic lymph nodes by FDG PET/CT in patients with asbestos-related lung cancer

Background

This study explored the assessment of intrathoracic lymph node metastasis by 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography computed tomography (PET/CT) in patients with asbestos-related lung cancer (ARLC).

Methods

We retrospectively reviewed the data on 35 patients with ARLC who underwent preoperative FDG-PET/CT and surgical resection between January 2012 and December 2018. We collected medical information from medical records and imaging systems and examined the FDG uptake in each lymph nodal region resected by surgery and the presence or absence of pathological lymph node metastasis.

Results

Pathological lymph node metastases were detected in 14 (8.70%) of 161 nodal stations. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT were 71.4% (10/14), 87.8% (129/147), 35.7% (10/28), 97.0% (129/133), and 86.3% (139/161), respectively. Six of the eight false-positive patients had bilateral accumulations, whereas all six true-positive patients had unilateral accumulation (P=0.006). On histopathological examination, the false-positive nodes showed disruption of lymphoid follicles in the cortex, infiltration of histiocyte-like cells in the medulla, fibrous micronodules, and severe anthracosis.

Conclusions

PET/CT scans of patients with ARLC showed comparable sensitivity and specificity to those of PET/CT scans of patients with conventional lung cancer reported in the literature. Many false-positive cases also showed bilateral symmetric accumulation. This method can be used to evaluate lymph node involvement in lung cancer.

Recent advances in diagnostic technologies in lung cancer

The increase in lung cancer incidence of Korea has been dampened since 2000; however, increased human lifespan, interest in health care and the widespread implementation of health examinations have resulted in a considerable rise in detection of small lesions that need to be differentiated from lung cancer. Detection of lung cancer at an early stage rather than at a symptomatic advanced stage is also increasing, suggesting that there are increasing diagnostic demands for small peripheral lung lesions. The development of new molecular diagnostics, including next generation sequencing, companion diagnostics that accompany development of new anti-cancer drugs, and re-biopsy for application of new therapeutic modality accelerate the development of lung cancer diagnostics. In this review, we extensively describe the current available diagnostic tools in lung cancer.

The diagnostic accuracy of endobronchial ultrasound and spiral chest computed tomography scan in the prediction of infiltrating and non-infiltrating lymph nodes in patients undergoing endobronchial ultrasound

Purpose

Endobronchial ultrasound (EBUS) and spiral chest computed tomography (CT) scan are important methods in the prediction of infiltrating and non-infiltrating lymph nodes, and the determination of their diagnostic accuracy would result in a reduction of the burden of problems and an improvement in prognosis. The purpose in this study was to determine the diagnostic accuracy of endobronchial ultrasound and spiral chest CT scan in the prediction of infiltrating and non-infiltrating lymph nodes in patients undergoing endobronchial ultrasound.

Material and methods

In this observational prospective study, 40 consecutive patients with infiltrating and non-infiltrating lymph nodes in Masih-Daneshvari Hospital in 2017 and 2018 were enrolled, and the sensitivity, specificity, and accuracy of EBUS and CT-scan versus fine needle aspiration pathology results were determined in them.

Results

The results in this study demonstrated that the congruence between EBUS and CT scan was 80.5% (p = 0.0001). The sensitivity, specificity, and accuracy for CT scan were 100%, 22.6%, and 40%, respectively, and the sensitivity, specificity, and accuracy for EBUS were 100%, 16.1%, and 35%, respectively.

Conclusion

According to the obtained results, it may be concluded that CT scan and EBUS results have good congruence and high sensitivity to differentiate infiltrating and non-infiltrating lymph nodes. Hence, these methods are useful for screening methods, but due to their low specificity and accuracy the use of them for a confirmative approach is not beneficial. However, regarding the accessibility and less invasive nature, use of chest CT scan is more rational and is recommended in these patients.