Unique Clinical Features of Imaging-Stage I Peripheral Lung Squamous Cell Carcinoma: A Retrospective Study.

The incidence of peripheral lung squamous cell carcinoma (p-LUSC) has increased in recent years, but the clinical features of early-stage p-LUSC remain unclear. In the present study, we aim to elucidate the general clinical features of p-LUSC by comparing it with peripheral lung adenocarcinoma (p-LUAD). Patients with p-LUSC or p-LUAD who were at an early imaging stage and underwent complete lobectomy with systematic lymph node dissection were included. The clinical characteristics of p-LUSC were elucidated through comparative analysis with p-LUAD, and independent prognostic factors for recurrence-free survival were identified. A total of 103 patients with p-LUSC and 600 patients with p-LUAD were included. Compared with p-LUAD, all p-LUSC cases appeared as solid nodules (SDNs) on imaging, and p-LUSC was associated with the male sex, older age, smoking history, lobulation sign, interstitial pneumonia, and a shorter volume doubling time. In terms of malignant aggressiveness, p-LUSC demonstrated a significantly lower lymph node metastasis rate than SDNs of p-LUAD in the >2.0 to ≤3.0 cm group, while no statistically significant difference was observed between the two groups in the 0-2.0 cm group. As for prognosis, tumor size and lymph node metastasis were found as independent risk factors for tumor recurrence.