Diagnostic Accuracy of the WHO System for Reporting Lung Cytopathology: A Retrospective Analysis.

Background: Lung cancer is the leading cause of cancer-related deaths globally, with early diagnosis crucial for improving survival. The 2023 WHO reporting system for lung cytopathology aims to standardize diagnostic criteria. This study assesses the system's diagnostic accuracy.

Materials and methods: This retrospective study analyzed 207 respiratory tract cytology samples (bronchoalveolar lavage/bronchial washing and endobronchial ultrasound-guided transbronchial needle aspiration) from January 2023 to June 2024. Samples were classified into five WHO categories: Nondiagnostic, Benign, Atypical, Suspicious for Malignancy, and Malignant. Histological correlation was performed where available. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated using histological diagnosis as the reference.

Results: Patients ranged from 27 to 87 years old, with a male-to-female ratio of 5.8:1. Sample distribution: Nondiagnostic (3.4%), Benign (63.7%), Atypical (6.3%), Suspicious for Malignancy (16.9%), and Malignant (9.6%). Histological correlation was available for 46.3% of cases. Risk of malignancy (ROM) was 25% for Nondiagnostic, 25.7% for Benign, 44.4% for Atypical, 93.5% for Suspicious for Malignancy, and 100% for Malignant. Highest sensitivity (84.75%) and NPV (74.29%) were achieved when Atypical, Suspicious for Malignancy, and Malignant categories were considered positive for malignancy.

Conclusion: The 2023 WHO reporting system for lung cytopathology offers a standardized and accurate diagnostic framework, enhancing patient management. Further studies are recommended to validate these results.