OBJECTIVE: The detection rates of small lung cancers, especially adenocarcinoma, have recently increased. An understanding of malignant aggressiveness is critical for the selection of suitable therapeutic strategies, such as sublobar resection. The objective of this study was to examine the malignant biological behavior of clinical stage IA adenocarcinoma and to select therapeutic strategies using high-resolution computed tomography, fluorodeoxyglucose-positron emission tomography/computed tomography, and a pathologic analysis in the setting of a multicenter study. METHODS: We performed high-resolution computed tomography and fluorodeoxyglucose-positron emission tomography/computed tomography in 502 patients with clinical T1N0M0 adenocarcinoma before they underwent surgery with curative intent. We evaluated the relationships between clinicopathologic characteristics and maximum standardized uptake values on fluorodeoxyglucose-positron emission tomography/computed tomography, ground-glass opacity ratio, and tumor disappearance rate on high-resolution computed tomography and component of bronchioloalveolar carcinoma on surgical specimens, as well as between these and surgical findings. We used a phantom study to correct the serious limitation of any multi-institution study using positron emission tomography/computed tomography, namely, a discrepancy in maximum standardized uptake values among institutions. RESULTS: Analyses of receiver operating characteristic curves identified an optimal cutoff value to predict high-grade malignancy of 2.5 for revised maximum standardized uptake values, 20% for ground-glass opacity ratio, 30% for tumor disappearance rate, and 30% for bronchioloalveolar carcinoma ratio. Maximum standardized uptake values and bronchioloalveolar carcinoma ratio, tumor disappearance rate, and ground-glass opacity ratio mirrored the pathologic aggressiveness of tumor malignancy, nodal metastasis, recurrence, and prognosis, including disease-free and overall survival. CONCLUSIONS: Maximum standardized uptake value is a significant preoperative predictor for surgical outcomes. High-resolution computed tomography and fluorodeoxyglucose-positron emission tomography/computed tomography findings are important to determine the appropriateness of sublobar resection for treating clinical stage IA adenocarcinoma of the lung.
OBJECTIVE: The detection rates of small lung cancers, especially adenocarcinoma, have recently increased. An understanding of malignant aggressiveness is critical for the selection of suitable therapeutic strategies, such as sublobar resection. The objective of this study was to examine the malignant biological behavior of clinical stage IA adenocarcinoma and to select therapeutic strategies using high-resolution computed tomography, fluorodeoxyglucose-positron emission tomography/computed tomography, and a pathologic analysis in the setting of a multicenter study. METHODS: We performed high-resolution computed tomography and fluorodeoxyglucose-positron emission tomography/computed tomography in 502 patients with clinical T1N0M0 adenocarcinoma before they underwent surgery with curative intent. We evaluated the relationships between clinicopathologic characteristics and maximum standardized uptake values on fluorodeoxyglucose-positron emission tomography/computed tomography, ground-glass opacity ratio, and tumor disappearance rate on high-resolution computed tomography and component of bronchioloalveolar carcinoma on surgical specimens, as well as between these and surgical findings. We used a phantom study to correct the serious limitation of any multi-institution study using positron emission tomography/computed tomography, namely, a discrepancy in maximum standardized uptake values among institutions. RESULTS: Analyses of receiver operating characteristic curves identified an optimal cutoff value to predict high-grade malignancy of 2.5 for revised maximum standardized uptake values, 20% for ground-glass opacity ratio, 30% for tumor disappearance rate, and 30% for bronchioloalveolar carcinoma ratio. Maximum standardized uptake values and bronchioloalveolar carcinoma ratio, tumor disappearance rate, and ground-glass opacity ratio mirrored the pathologic aggressiveness of tumor malignancy, nodal metastasis, recurrence, and prognosis, including disease-free and overall survival. CONCLUSIONS: Maximum standardized uptake value is a significant preoperative predictor for surgical outcomes. High-resolution computed tomography and fluorodeoxyglucose-positron emission tomography/computed tomography findings are important to determine the appropriateness of sublobar resection for treating clinical stage IA adenocarcinoma of the lung.