Prognostic significance of combined radiologic imaging modalities for prognosis of clinical IA adenocarcinomas.

BACKGROUND: We previously proposed measuring tumor size using mediastinal window setting on high-resolution computed tomography (CT) as a simple and useful modality for preoperative prognostication of small adenocarcinoma. Hence, the importance of tumor volume and positron emission tomography (PET) for preoperative prognostication of clinical stage IA (cIA) adenocarcinoma was studied.

MATERIALS AND METHODS: We retrospectively evaluated total 324 patients who underwent pulmonary resection of cIA adenocarcinoma between July 2008 and August 2015. Reconstructed three-dimensional (3D) images from 1-1.5 mm-sliced CT were evaluated for whole tumor volume including ground grass opacity, consolidation volume on lung window setting, and mediastinal window volume (MWV). The values examined by PET were total lesion glycolysis (TLG), and maximum standardized uptake (SUV max) and mean. Pathologic status was evaluated according to tumor maximum size, invasive size (IS), lymphatic and vascular vessels, pleural invasion (ly/v/pl), and TNM staging.

RESULTS: According to ly/v/pl invasion and lymph node positivity, no variables were superior to IS. We used Mean/MWV (SUV mean x MWV) to evaluate tumor quality and quantity in the role of surrogate TLG. Mean/MWV were superior to IS. Additionally, Mean/MV was associated with lymph node metastases. Among the various histologic subtypes, solid-predominant had the highest expression of Mean/MV. The higher Mean/MV significantly contributed to unfavorable disease-free survival in cIA adenocarcinomas, but not to overall survival.

CONCLUSIONS: The mean/MWV value determination on 3D-reconstructed CT images was a simple and useful preoperative modality for predicting invasive facet in cIA adenocarcinoma. However, higher values didn't significantly affect overall survival.