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

Abstract Objective 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). Methods Clinical data of 247 patients were collected and clinicopathological features were retrieved, including gender, age, smoking history, tumor location, stage (AJCC 7th), and distant metastasis. Histopathological features were also reviewed by two pathologists, including pleural invasion, bronchial invasion, nerve invasion, spread though 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, ChromograninA) was also reviewed. All patients were followed up for recurrence, distant metastasis and survival. Kaplan-Meier curve and log-rank test were applied for survival analysis. Results 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, stage, distant metastasis, regional lymph node metastasis, nerve invasion, major cell shape and TILs). Multivariate analysis revealed DFS-related factors (stage, nerve invasion, major cell shape and TILs) and OS-related factors (age, stage, distant metastasis in brain, liver, bone, pleural invasion, nerve invasion, major cell shape and TILs). Conclusion Age>65y, advanced stage (T and N), distant metastasis, nerve invasion and TILs 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.