The Role and Associated Factors of Liquid-Based Cytology of Bronchoalveolar Lavage Fluid in Lung Cancer Diagnosis: A Prospective Study.

Background Liquid-based cytology (LBC) has shown advantages over conventional smears (CS), but previous applications in bronchoalveolar lavage (BAL) fluid have produced inconsistent results. This study compared LBC and CS for diagnosing lung cancer using BAL fluid. Methodology A prospective study was conducted on 92 patients suspected of having lung cancer. All patients underwent bronchoscopy and had a final diagnosis confirmed by histopathology of lesions tissue through biopsy. The study aimed to assess the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the two cytological methods, in a pair-wise fashion. In addition, the study evaluated the correlation of factors, such as the volume of fluid used in LBC and bronchoscopy lesion morphology, with the sensitivity of LBC. Results The study involved 78 participants who were diagnosed with lung cancer. The sensitivity, specificity, PPV, and NPV of LBC were 25.7%, 100%, 100%, and 19.4%, respectively, whereas those of CS were 15.4%, 85.7%, 85.7%, and 15.4%, respectively. Although the sensitivity of LBC was higher than that of CS, the difference was not statistically significant (p=0.096, McNemar test). Furthermore, the median fluid volume performed during LBC in patients with positive results was significantly higher than in those with negative results (p=0.001, Mann-Whitney U test). Conclusions The application of LBC to BAL fluid has demonstrated similar and potentially superior diagnostic accuracy compared to CS in detecting lung cancer. It is recommended that further investigation be undertaken to examine the relationship between the volume of fluid utilized during the LBC process and its diagnostic accuracy to enhance its sensitivity.