Comparison between solid component size on thin-section CT and pathologic lymph node metastasis and local invasion in T1 lung adenocarcinoma.

Objectives: To correlate the tumor size and solid component size on thin-section CT (TS-CT) with pathological findings including lymph node (LN) metastasis and local invasion in T1 lung adenocarcinoma.

Methods: 188 patients with surgically resected T1 lung adenocarcinoma were retrospectively analyzed. Two chest radiologists measured the long-axis and short-axis dimensions of nodules and solid components with a lung and/or a mediastinal window setting (WS) on TS-CT. After analyzing interobserver agreement, average long-axis dimensions of the measured tumors and solid components were correlated with pathological findings.

Results: Seven of 188 patients (3.7%) had pathologic LN-positive metastasis. In patients in whom the long axis of the solid component was <5 mm with a mediastinal WS or <8 mm with a lung WS on TS-CT, no LN metastases were observed, resulting in a positive predictive value (PPV) for predicting a pathologic LN-negative status of 100% with each WS. Based on the same diagnostic criteria, the PPVs for a pathological local invasion (LI)-negative status were 91 (40/44) and 90% (55/61), respectively.

Conclusion: Solid component size on TS-CT may have the potential to predict LN-negative or LI-negative status.