Diagnostic Accuracy of the Who Reporting System for Lung Fine-Needle Aspiration Biopsies: A Systematic Review and Meta-Analysis Publisher



Ahuja S ; Fattahidarghlou M ; Ahuja R ; Kabra AP ; Zaheer S
Source: Journal of the American Society of Cytopathology Published:2026

Abstract

Introduction: The World Health Organization (WHO), together with the International Academy of Cytology and the International Agency for Research on Cancer, has introduced a standardized framework for reporting lung cytopathology. This approach clarifies diagnostic tiers, provides malignancy risk estimates, and integrates with the latest WHO Tumour Classification. Derived partly from the Papanicolaou Society of Cytopathology model, it strengthens diagnostic reproducibility and clinical risk categorization. The aim of this study is to evaluate the diagnostic accuracy of fine-needle aspiration biopsy (FNAB) in lung lesions reported under the WHO system. Materials and methods: A comprehensive search of Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov and conference abstracts was carried out using predefined terms (lung, diagnostic accuracy, FNAB). Studies applying the WHO reporting scheme to lung FNAB were eligible, with histopathology or clinical follow-up as reference standards. Meta-analysis examined sensitivity and specificity at 3 thresholds: (1) malignant only, (2) suspicious or higher, and (3) atypical or higher. Pooled diagnostic odds ratios and summary receiver operating characteristic analyses were undertaken. Results: Four studies met inclusion criteria. Risk of malignancy increased across WHO categories, from 27% in benign to 92% in malignant. Sensitivity and specificity differed by cut-off: malignant only (33%, 100%), suspicious or higher (73%, 96%), atypical or higher (83%, 84%). Aggregate diagnostic odds ratios and summary receiver operating characteristic curves supported the diagnostic robustness of the system. Conclusions: The WHO reporting system provides effective stratification of lung FNABs. Defining positivity at “suspicious” or higher offers the best diagnostic balance, while including “atypical” increases sensitivity with minimal loss of specificity, supporting its clinical utility. © 2026 Published by Elsevier Inc. on behalf of American Society of Cytopathology.