Sublobar Resection in Stage IA Non-Small Cell Lung Cancer: Role of Preoperative CT Features in Predicting Pathologic Lymphovascular Invasion and Postoperative Recurrence

BACKGROUND. Prognostic factors on preoperative CT in stage IA non-small cell lung cancer (NSCLC) may help select patients for sublobar resection or lobectomy. OBJECTIVE. The purpose of this study was to identify CT features predictive of pathologic lymphovascular invasion (LVI) in stage IA NSCLC and to evaluate the features' prognostic value in patients who undergo sublobar resection. METHODS. This retrospective study included 904 patients (mean age, 62.0 years; 453 men, 451 women) who underwent lobectomy (n = 574) or sublobar resection (n = 330) for stage IA NSCLC. Two thoracic radiologists independently evaluated findings on preoperative chest CT and then resolved discrepancies. Recurrences were identified from medical record review. Multivariable logistic regression was used to identify independent predictors of pathologic LVI. Multivariable Cox proportional hazards models were used to identify prognostic features. Interreader agreement was assessed. RESULTS. Pathologic LVI was present in 10.2% (92/904) of patients. It was present only in solid-dominant part-solid nodules (PSNs) and solid nodules and only in nodules with a solid portion diameter over 10 mm. Among solid-dominant PSNs and solid nodules with a solid portion diameter over 10 mm, independent (p < .05) predictors of pathologic LVI were peritumoral interstitial thickening (odds ratio PRI, 13.22) and pleural contact (defined as pleural contact measuring over one-quarter of the circumference of the nodule's solid portion) (OR, 2.45). Also among such nodules, peritumoral interstitial thickening achieved 80.4% sensitivity, 76.7% specificity, and 77.4% accuracy; pleural contact achieved 35.9% sensitivity, 82.5% specificity, and 74.3% accuracy; and presence of either feature achieved 90.2% sensitivity, 64.3% specificity, and 68.9% accuracy for predicting pathologic LVI. In patients undergoing sublobar resection, after adjusting for T category and operative type, recurrence-free survival (RFS) was independently (p < .05) predicted by solid-dominant PSN or solid nodule with a solid portion diameter over 10 mm also showing peritumoral interstitial thickening (hazard ratio Din 5.37) or also showing either peritumoral interstitial thickening or pleural contact (HR, 6.05). The interreader agreement kappa values were 0.67 for peritumoral interstitial thickening and 0.77 for pleural contact. CONCLUSION. Pathologic LVI occurred only in solid-dominant PSNs and solid nodules with solid portion over 10 mm. Among such nodules, peritumoral interstitial thickening and pleural contact independently predicted pathologic LVI and RFS. CLINICAL IMPACT. CT features may help select patients with stage IA NSCLC for sublobar resection rather than more extensive surgery.