Development and internal validation of the OPERA-FE score incorporating area under the expiratory flow-volume curve for predicting postoperative complications after lung cancer surgery.

INTRODUCTION: Postoperative complications remain major determinants of prognosis after lung cancer surgery. Conventional pulmonary function parameters such as FEV1 and DLCO have limited predictive accuracy. We aimed to investigate the association between AreaFE and postoperative complications and to develop and internally validate a clinically applicable risk score integrating AreaFE with clinical and surgical variables. MATERIALS AND METHODS: This retrospective cohort study included 373 consecutive patients who underwent surgical resection for histopathologically confirmed lung cancer between October 2023 and October 2024. Preoperative spirometric flow-volume curves were analyzed using Python-based software to calculate AreaFE. Postoperative complications within 30 days were recorded according to the Clavien-Dindo classification. The dataset was randomly divided into a training cohort (80%) and a test cohort (20%). Multivariable logistic regression was performed in the training cohort, and a point-based risk score (OPERA-FE) was derived. Discrimination was assessed using ROC curve analysis and internally validated. RESULTS: Postoperative complications occurred in 132 patients (35.4%). Lower AreaFE values were significantly associated with complications. In the multivariable model, AreaFE ≤6.85, male sex, COPD, and operation time ≥180 min were associated with increased risk. The OPERA-FE score demonstrated good discrimination in the training cohort (AUC = 0.81) and maintained similar performance in the test cohort (AUC = 0.81). CONCLUSION: Lower preoperative AreaFE values independently predict postoperative complications after lung cancer surgery. The OPERA-FE score may support perioperative risk stratification.