Preoperative CT Findings for Predicting Acute Exacerbation of Interstitial Pneumonia After Lung Cancer Surgery: A Multicenter Case-Control Study.

Background: Acute exacerbation (AE) is a life-threatening complication of interstitial pneumonia (IP). Thoracic surgery may trigger AE. Objective: To explore the role of preoperative CT findings for predicting postoperative AE in patients with IP and lung cancer. Methods: This retrospective case-control study included patients from 22 institutions with IP who underwent thoracic surgery for lung cancer. AE was diagnosed based on symptoms and imaging findings within 30 days after surgery and absence of alternate causes. For each case of AE, two control cases without AE were identified. After exclusions, 92 patients (78 men, 14 women; mean age 72 years; 31 with AE, 61 without AE) were included. Two radiologists independently reviewed preoperative thin-slice CT examinations for pulmonary findings and resolved differences by consensus. AE and no-AE groups were compared using Fisher's exact and Mann-Whitney U tests. Multivariable logistic regression was performed. Interreader agreement was assessed by kappa coefficients. Results: A total of 94% of patients in AE group underwent segmentectomy or other surgery more extensive than wedge resection, versus 75% in no-AE group (p=.046). Usual interstitial pneumonia pattern was present in 58% of AE group versus 74% in no-AE group (p=.16). Using subjective visual scoring, mean ground glass opacity (GGO) extent was 6.3±5.4 in AE group versus 3.9±3.8 in no-AE group (p=.03), and mean consolidation extent was 0.5±1.2 in AE group versus 0.1±0.3 in no-AE group (p=.009). Mean pulmonary trunk diameter was 28±4 mm in AE group versus 26±3 mm in no-AE group (p=.02). In a model of only CT features, independent predictors of AE (p<.05) were GGO extent (OR=2.8), consolidation extent (OR=9.4), and pulmonary trunk diameter (OR=4.2); this model achieved AUC 0.75, PPV 71%, and NPV 77% for AE. When combing CT and clinical variables, undergoing segmentectomy or more extensive surgery also independently predicted AE (OR=8.2; p=.02). Conclusion: GGO, consolidation, and pulmonary trunk enlargement on preoperative CT predict AE in patients with IP undergoing lung cancer surgery. Clinical Impact: Patients with IP and lung cancer should be carefully managed in the presence of the predictive CT features. Wedge resection, if possible, may help reduce AE risk in these patients.