Contribution of endoscopic ultrasound-guided fine-needle aspiration in the workup of mediastinal lymph nodes

High Diagnostic Accuracy and Safety of Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Malignant Lymph Nodes: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is increasingly being used for diagnosing lymphadenopathy. We aim to systematically review the accuracy of EUS-FNA in differentiating benign and malignant mediastinal and abdominal lymph nodes (LNs).

METHODS

A comprehensive literature search was performed on multiple electronic databases through February 2020. A random or fixed effect model generated the pooled sensitivity, specificity, likelihood ratio (LR), and diagnostic odds ratio (DOR) of EUS-FNA. Subgroup analyses and meta-regression were used to explore sources of heterogeneity.

RESULTS

Twenty-six studies involving 2753 patients with 2833 LNs were included. In the differential diagnosis of benign and malignant LNs, EUS-FNA had a pooled sensitivity, specificity, positive LR, and negative LR of 87% (95% confidence interval [CI] 86-90%), 100% (95% CI 99-100%), 68.98 (95% CI 42.10-113.02), and 0.14 (95% CI 0.11-0.17), respectively. The pooled rate of adverse events associated with EUS-FNA was 1.57% (95% CI 1.06-2.24%). The summary receiver operating characteristic (SROC) yielded an area under the curve (AUC) of 0.9912. EUS-FNA performed in mediastinal LNs gained a sensitivity of 85% (95% CI 81-88%), while in abdominal LNs, it reached 87% (95% CI 82-91%). The sensitivity of the subgroup with rapid on-site evaluation (ROSE) was 91% (95% CI 89-93%), while non-ROSE was 85% (95% CI 82-87%).

CONCLUSIONS

EUS-FNA is a sensitive, highly specific, and safe method for distinguishing benign and malignant mediastinal or abdominal LNs. However, the sensitivity of EUS-FNA still varies significantly among different centers.

Endoscopic ultrasound guided fine-needle aspiration of lymph nodes and solid masses: factors influencing the cellularity and adequacy of the aspirate

GOALS

To study the factors that influence the cellularity and adequacy of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA).

BACKGROUND

An on-site cytopathology service is preferred during EUS-guided FNA. However, this is not always available. Factors that influence the aspirate cellularity and adequacy have not been well defined in the absence of on-site cytopathology.

STUDY

EUS-guided FNA procedures without an on-site cytopathologist from a single center were retrospectively studied. FNA of solid masses and lymph nodes (LN) were included. The FNA cellularity, hemorrhagic content, and endoscopists' assessment of adequacy were analyzed.

RESULTS

A total of 166 patients from January 2009 to October 2010 were included. A total of 520 FNA passes were performed. Of the 166 lesions, 70 (42.2%) were solid masses and 96 (57.8%) were LNs. A 22-G needle was used in 72.3% and 25 G in 27.7% of the patients. The median (range) number of FNA passes was 3 (1 to 7) for LNs and 3 (1 to 5) for solid masses. With this, the endoscopists had an accuracy of 92.2% (153/166) for obtaining an adequate aspirate. Of the 166 samples, 4 (2.4%) were acellular, 20 (12.0%) sparsely cellular, 52 (31.4%) moderately cellular, and 90 (54.2%) highly cellular. The 25-G needle had significantly more adequate aspirates than the 22-G needle for solid masses (P=0.011). Also, increasing passes correlated with higher cellularity (P=0.002) and an adequate aspirate (P=0.021). No correlation was found for LN FNA. Lesion size did not influence the cellularity or adequacy (P>0.05). The degree of hemorrhage was not influenced by the needle gauge, number of passes, or lesion size. The diagnostic yield was not affected by hemorrhage in the sample (P>0.05).

CONCLUSIONS

EUS-guided FNA obtains a high proportion of adequate aspirates for LNs and solid masses, even without an on-site cytopathologist. Small proportions of inadequate samples still occur. For solid masses, a 25-G needle with at least 3 passes is more likely to provide an adequate aspirate than a 22-G needle and fewer passes. Hemorrhage did not affect the cytopathology's ability to make a diagnosis.

[Role of endoscopic ultrasound (EUS) and endobronchial ultrasound (EBUS) for the evaluation of mediastinal adenopathy]

Mediastinal lymphadenopathy may be detected by CT-scan or positron emission tomography. Malignant (e.g, lung cancer, metastatic cancer, lymphoma), infectious (e.g, tuberculosis, histoplasmosis), and systemic processes (e.g, sarcoidosis) can cause mediastinal adenopathy. In the posterior and inferior mediastinum, endoscopic ultrasound visualizes and directs transesophageal fine needle aspiration of adenopathy. In the anterior mediastinum, endobronchial ultrasound visualizes and directs transbronchial fine needle aspiration of adenopathy. We discuss the role of EUS and EBUS in the evaluation of mediastinal adenopathy according to their anatomical localization.