# Ultrasound-guided fine-needle cytology for cervical lymph nodes: a tertiary centre’s experience with the Sydney system

## TL;DR

This study compares two ultrasound-guided fine-needle cytology methods for diagnosing cervical lymph nodes, finding that one method performs better for most sizes.

## Contribution

The study provides new evidence on the superior diagnostic performance of US-FNAC over US-FNNAC for cervical lymph nodes sized 5.1–15.0 mm.

## Key findings

- US-FNAC showed higher sensitivity and diagnostic accuracy than US-FNNAC for lymph nodes measuring 5.1–15.0 mm.
- US-FNAC is recommended as the preferred method for cervical lymph node evaluation in clinical practice.
- Lymph nodes ≤5.0 mm require additional tests to improve diagnostic performance.

## Abstract

To evaluate the diagnostic value of ultrasound-guided fine-needle aspiration cytology (US-FNAC) and ultrasound-guided fine-needle non-aspiration cytology (US-FNNAC) on cervical lymphadenopathies, in which the authors specifically analysed the influence of lymph node size.

A total of 500 lymphadenopathies were retrospectively enrolled from January 2019 to July 2023. The lymph nodes were divided into four size groups: ≤5.0 mm, from 5.1 to 10.0 mm, from 10.1 to 15.0 mm and >15.0 mm. The cytohistologic diagnosis was evaluated based on the Sydney System: I. inadequate/nondiagnostic; II. benign; III. atypical cells with uncertain significance/atypical lymphoid cells with undetermined significance; IV. Suspicious and V. malignant. The diagnostic yield of US-FNAC and US-FNNAC were assessed based on sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and accuracy calculations.

The overall SEN, SPE, PPV, NPV and accuracy of ultrasound-guided fine-needle cytology were 88.7%, 89.7%, 96.2%, 72.9%, 88.9%, respectively. The diagnostic accuracy and SEN of US-FNAC were superior to that of US-FNNAC in the overall cases (95.1% vs 83.9%, p < 0.001;95.6% vs 83.4%, p < 0.001) and in lymph nodes that measured from 5.1 to 10.0 mm(94.5% vs 85.1%, p = 0.022; 95.8% vs 84.4%, p = 0.021) as well as that from 10.1 to 15.0 mm (98.6% vs 86.0%, p = 0.011; 98.2% vs 83.3%, p = 0.011), while there was no significant difference between US-FNAC and US-FNNAC in the diagnostic yield among the other two subgroups.

The current findings supported the preferential use of US-FNAC over US-FNNAC in routine clinical practice for lymph node evaluation, particularly for nodes measuring 5.1–15.0 mm. For lymphadenopathies ≤5.0 mm, additional tests were required to enhance the diagnostic performance of US-FNC, with US-FNAC often being necessary. Thus, we recommended using US-FNAC to obtain cytological specimens for definitive diagnosis of cervical lymphadenopathies that ≤15.0 mm.