Comparison of radiological and pathological tumor sizes in resected non-small cell lung cancer

Objectives: In non-small cell lung cancer (NSCLC), T factor plays an important role in determining staging. The present study aimed to determine the validity of preoperative evaluation of clinical T (cT) factor by comparing radiological and pathological tumor sizes. Methods: Data for 1,799 patients with primary NSCLC who underwent curative surgery were investigated. The concordance between cT and pathological T (pT) factors was analyzed. Furthermore, we compared groups with an increase or decrease of ≥ 20% and groups with an increase or decrease of < 20% in the size change between preoperative radiological and pathological diameters. Results: The mean sizes of the radiological solid components and the pathological invasive tumors were 1.90 cm and 1.99 cm, respectively, correlation degree = 0.782. The group with increased pathological invasive tumor size (≥ 20%) compared with the radiologic solid component was significantly more likely female, consolidation tumor ratio (CTR) ≤ 0.5, and within cT1. Multivariate logistic analysis identified CTR < 1, cT ≤ T1, and adenocarcinoma as independent risk factors for increased pT factor. Conclusion: The radiological invasive area of tumors with cT1, CTR < 1, or adenocarcinoma on preoperative CT may be underestimated compared with pathological invasive diameter.