Prognostic factors for surgically resected non-small cell lung cancer with cavity formation

Small pulmonary nodules have been detected frequently by computed tomography (CT). Lung cancers with cavity formation are also easily detected. There are a few reports focused on the cavity wall, although cancer cells exist along the cavity wall, not inside. We evaluated the impact of cavity wall thickness on prognosis and assessed the clinicopathological features in non-small cell lung cancer (NSCLC) with cavity formation.

Between 2005 and 2011, 1,313 patients underwent complete resection for NSCLC. Of these cases, we reviewed 65 patients (5.0%) diagnosed with NSCLC with cavity formation by chest CT. We classified the patients into three groups based on the maximum cavity wall thickness, namely, ≤4 mm (Group 1, 8 patients), >4 and ≤15 mm (Group 2, 33 patients), and >15 mm (Group 3, 24 patients).

The number of patients with pathological whole tumor size >3 cm was 2 (25%) in Group 1, 17 (52%) in Group 2, and 23 (96%) in Group 3 (P<0.001). Cases with lymph node metastasis were 0 (0%) in Group 1, 5 (15%) in Group 2, and 10 (42%) in Group 3 (P=0.016). The 5-year overall survival (OS) rates were 100% in Group 1, 84.0% in Group 2, and 52.0% in Group 3, with significant differences between Group 1 and Group 3 (P=0.044) and between Group 2 and Group 3 (P=0.034). In univariate analysis, neither whole tumor size nor lymph node metastasis was a prognostic factor for OS (P=0.51, P=0.27). Only cavity wall thickness was a significant prognostic factor by multivariate analysis (P=0.009).

Maximum cavity wall thickness was an important prognostic factor in NSCLCs with cavity formation, comparable with other established prognostic factors.