Solitary Pulmonary Nodular Lung Adenocarcinoma: Correlation of Histopathologic Scoring and Patient Survival with Imaging Biomarkers

Abstract

PURPOSE: To evaluate the usefulness of histopathologic scoring for survival prediction in patients with solitary pulmonary nodular (SPN) lung adenocarcinomas and to correlate the histopathologic scoring with the results of computed tomography (CT) and fluorine 18 fluorodeoxyglucose positron emission tomography (PET)/CT. MATERIALS AND METHODS: This retrospective study was institutional review board approved and the requirement for informed consent was waived. A total of 148 patients with SPN lung adenocarcinoma underwent PET/CT and CT. Correlations between histopathologic scores estimated by using two predominant histologic subtypes from each surgically resected specimen and the mass of the nodule at CT or maximum standardized uptake value (SUV(max)) at PET/CT were assessed. Disease-free survival (DFS) was estimated by using the Kaplan-Meier method, and the log-rank test was used to evaluate differences in each histopathologic subtype. RESULTS: In 135 (91%) patients, tumors had a mixed subtype. The most frequently observed histologic subtypes, in decreasing order, were acinar (51%), lepidic (18%), solid (10%), and papillary (9%). DFS rates at 5 years were higher than 90% for the group of patients with nodules that showed the lepidic growth pattern, and 50% for patients with nodules that showed the micropapillary pattern. The pathologic score proved to be a significant predictor of DFS (P < .001). Both SUV(max) and the mass of the nodule were closely correlated with pathologic score. CONCLUSION: Pathologic scoring appears to help predict DFS in patients with SPN lung adenocarcinoma and shows close correlation with imaging biomarkers including the mass of the nodule at CT and SUV(max) at PET/CT.