Clinicopathological features and prognostic analysis of 247 small cell lung cancer with limited-stage after surgery

The objective of this study was to analyze the clinical and pathological characteristics of patients with small cell lung cancer (SCLC) after curative surgery and to explore prognostic factors for disease-free survival (DFS) and overall survival (OS). Clinical data of 247 patients were collected, and clinicopathological features were retrieved, including gender, age, smoking history, tumor location, and distant metastasis. Histopathological features were also reviewed by three pathologists, including primary tumor (T), lymph node metastasis (N), pleural invasion, bronchial invasion, nerve invasion, spread through air spaces (STAS), tumor thrombosis, major cell shape (round Vs. spindle), tumor necrosis, stromal fibrosis, and tumor-infiltrating lymphocytes (TILs). Immunohistochemical staining of neuroendocrine markers (CD56, synapsin, chromogranin A) was also reviewed. All patients were followed up for recurrence, distant metastasis, and survival. Kaplan-Meier curves and log-rank tests were applied for survival analysis. The median DFS was 98 months, and the 1-year, 3-year, and 5-year DFS rates were 70.9%, 54.4%, and 52.2%, respectively. The median OS was not reached, and the 1-year, 3-year, and 5-year survival rates were 94.2%, 72.3%, and 65.4%, respectively. Univariate analysis revealed clinicopathological features with DFS (gender, smoking history, primary tumor, regional lymph node metastasis, major cell shape, and TILs) and OS (age, primary tumor, regional lymph node metastasis, distant metastasis, nerve invasion, major cell shape, and TILs). Multivariate analysis revealed DFS-related factors (smoking history, regional lymph node metastasis and major cell shape) and OS-related factors (age, primary tumor, distant metastasis in the brain, liver, bone, nerve invasion, and TILs). Age more than 65 years, smoking, advanced stage (T and N), distant metastasis, nerve invasion, major cell shape as spindle and TILs >30% were negatively correlated with survival. Neuroendocrine immunostaining markers showed no correlation with survival. Of interest, spindle cell type and TILs >30% are revealed as independent negative prognostic factors, and further molecular mechanisms need to be explored.