Further understanding of an uncommon disease of combined small cell lung cancer: clinical features and prognostic factors of 114 cases

OBJECTIVE: Combined small cell lung cancer (C-SCLC) is an uncommon subgroup of small cell lung cancer (SCLC) and few clinical data can be referred. Our study is to investigate the clinical features and prognostic factors of C-SCLC, as well as the role of multimodality treatment. METHODS: Between January 2004 and December 2012, patients with histologically diagnosed C-SCLC were retrospectively analyzed. The survivals were evaluated with the Kaplan-Meier method. Univariate and multivariate analyses were used to evaluate potential prognostic factors. RESULTS: One hundred and fourteen patients were enrolled, with a median age of 59 (range: 20−79) years old. The most common combined component was squamous cell carcinoma (52.6%). Among these patients, the disease was stage I, II, III and IV in 9.6%, 19.3%, 46.5% and 24.6% of the patients, respectively. Eighty patients (70.2%) received at least two of the three modalities containing chemotherapy, radiotherapy and surgery. The median follow-up was 32.5 months. The median time of overall survival (OS) was 26.2 months. On univariate analysis, smoking (P=0.029), Karnofsky performance score (KPS) <80 (P=0.000), advanced TNM stage (P=0.000), no surgery (P=0.010), positive resection margin (P=0.000), positive lymph nodes ≥4 (P=0.000), positive lymph node ratio >10% (P=0.000) and non-multimodality treatment (P=0.004) were associated with poor OS. Multivariate analysis confirmed that smoking, advanced TNM stage, positive resection margin and positive lymph nodes ratio >10% were poor prognostic features. CONCLUSIONS: C-SCLC has a relatively early stage and good prognosis, which may due to the underestimated diagnosis in non-surgical patients. Multimodality therapy is recommended, especially for limited disease. Smoking, advanced TNM stage, positive resection margin and positive lymph nodes ratio >10% are poor prognostic factors.