Prediction of pathologic prognostic factors in patients with lung adenocarcinomas: comparison of thin-section computed tomography and positron emission tomography/computed tomography

BACKGROUND The ratio of the maximum diameter of consolidation to the maximum tumor diameter (C/T ratio) on thin-section computed tomography (TSCT) and the maximum standardized uptake value (SUVmax) on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) are often used as preoperative independent variables to evaluate the invasiveness of lung adenocarcinoma. We investigated the associations between these independent variables and pathologic invasiveness in pulmonary adenocarcinomas. METHODS We selected patients with peripheral lung adenocarcinomas, definitively diagnosed by surgical resection, with diameters of ≤ 30 mm over a 4-year period ending in December 2010. The association between 3 independent variables (tumor size, SUVmax, and C/T ratio) and pathologic prognostic factors was evaluated using logistic analysis. RESULTS We evaluated a total of 163 primary lung adenocarcinomas in 148 patients (93 males and 55 females; age range: 34 to 84 years). Using multivariate logistic regression analysis, SUVmax and the C/T ratio were significantly associated with tumor invasiveness (odds ratio [OR] = 1.227; p = 0.025 and OR = 1.019; p = 0.008, respectively). Tumor size was not associated with invasiveness (OR = 1.003; p = 0.925). For solid type adenocarcinomas, only SUVmax was significantly associated with invasiveness (OR = 1.558; p = 0.003). For subsolid type adenocarcinomas, only the C/T ratio was significantly associated with invasiveness (OR = 1.030; p = 0.009). CONCLUSIONS Both the C/T ratio and the SUVmax are significantly correlated with pathologic invasiveness in patients with small lung adenocarcinomas, while there was a difference between the 2 evaluations. Solid type adenocarcinomas with SUVmax values of ≥ 4.4 and subsolid type adenocarcinomas with C/T ratio ≥ 53% were so highly invasive.