Clinical Outcome of Resected Solid-type Small-sized C-stage IA Non-small Cell Lung Cancer

Background: The chances of pulmonary resection for small-sized lung cancer have increased because of the development of thin-slice computed tomography (CT). Though sublobar resection could be indicated for ground glass opacity (GGO)-dominant adenocarcinoma with low-grade behaviour, the malignant potential of solid-type, small-sized lung cancer has not been sufficiently assessed. We aimed to address the clinical outcomes of resected solid-type c-stage IA non-small cell lung cancer (NSCLC) smaller than 2 cm.

Methods: A retrospective observational study involving 118 patients who had undergone a complete resection for lung cancer smaller than 2 cm with solid component more than 50% on CT was conducted, and their postoperative survival and recurrence pattern were analysed.

Results: Thirty-five patients with solid component-dominant lesion (SCDL) and 83 patients with pure solid lesion (PSL) without GGO were enrolled. Lymph node involvement was found in 15 patients with PSL (18%). The 5-year disease-free survival (DFS) was 100% in SDCL patients and 83% in PSL patients. Multivariate analysis of PSL patients showed that lymph node metastasis and pleural invasion were independent negative prognostic predictors. The 5-year DFS was 88%, 80% and 46% in p-N0, p-N1 and p-N2 patients, respectively. The 5-year DFS was 33% for patients with pleural invasion, which was significantly worse than that for patients without pleural involvement. Postoperative recurrence was mainly observed as intrathoracic lesions within 3 years.

Conclusions: A proportion of solid-type NSCLC has malignant potential, even for tumours smaller than 2 cm. Periodic intrathoracic evaluation is required following complete resection.