Diagnostic Accuracy of Bronchoalveolar Lavage and Bronchial Brushing Cytology, Alone and in Combination, in Patients with Histologically Confirmed Lung Adenocarcinoma and Squamous Cell Carcinoma

Abstract

Introduction: Bronchoalveolar lavage (BAL) and bronchial brushing (BB) are minimally invasive cytology techniques used during the diagnostic work-up of lung cancer. They sample different anatomic compartments. Their performance for lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) may differ. This study evaluated their subtype-specific diagnostic performance, alone and in combination, using histopathology as the reference standard.
Method: This retrospective paired diagnostic-accuracy study included 38 patients at Prof. dr. Chairuddin Panusunan Lubis Teaching Hospital, Medan, from January 2023 to June 2024. All underwent BAL, BB, and lung biopsy. Cytology was evaluated on Giemsa-stained preparations and histopathology on hematoxylin and eosin-stained sections. Sensitivity and subtype-specific specificity, with exact 95% confidence intervals (CIs), were calculated for concordant cytologic subtype assignment.
Results: Histopathology showed ADC in 21 patients and SCC in 17. BAL sensitivity for ADC was 95.2% (95% CI: 76.2–99.9), compared with 76.2% (95% CI: 52.8–91.8) for BB. For SCC, BAL sensitivity was 47.1% (95% CI: 23.0–72.2) and BB sensitivity was 94.1% (95% CI: 71.3–99.9). The combined strategy matched the more sensitive individual test for each subtype. No cross-subtype cytologic assignments occurred; subtype-specific specificity was 100%, with wide CIs due to the small non-target groups.
Conclusion: BAL demonstrated higher sensitivity for ADC, whereas BB demonstrated higher sensitivity for SCC; together, the techniques can provide complementary preliminary cytologic information, although histopathological confirmation remains necessary.