Clinical Features And Role Of Radiotherapy In Combined Small Cell Lung Cancer

Objective:To investigate the clinical features, prognostic factors, as well as the role of radiotherapy in combined small cell lung cancer (C-SCLC).Methods:Between Jan.2004to Dec.2012, patients with histologically diagnosed C-SCLC in our hospital were retrospectively analyzed. Kaplan-Meier analyses were used to assess survival. The Logrank test was used to examine differences between different groups. Cox’s proportional hazards model was used for multivariate analysis. A two-sided P-value of <5%was considered statistically significant.Results:One hundred and fourteen patients were enrolled, with a median age of59years old. The most common combined component was squamous cell carcinoma (52.6%). The disease of stage Ⅰ, Ⅱ, Ⅲ and Ⅳ was9.6%,19.3%,46.5%and24.6%, respectively. Most patients (N=80,70.1%) received multimodality treatment. Ninety-six patients (84.2%) were treated with chemotherapy,66(57.9%) with surgery, and48(42.1%) with radiotherapy. The median follow-up was32.5months. The median time of OS, PFS and LRFS was26.2,13.1and26.5months, respectively. The1-,3-and5-year OS was76.6%,42.8%and37.4%, respectively, with the corresponding PFS of52.2%,33.9%, and29.0%and LRFS of68.5%,43.0%and37.3%, respectively. The median DMFS of patients with stage Ⅰ-Ⅲ disease was22.7months, with1-,3-and5-year DMFS of61.2%,46.6%and35.7%, respectively. On univariate analysis, smoking (P=0.029), KPS<80(P=0.000), advanced stage (P=0.001,0.000), no surgery (P=0.010), positive resection margin (P=0.000), positive lymph nodes>4(P=0.000), and positive lymph node ratio>10%(P=0.000) were associated with poor OS. Multivariate analysis confirmed smoking, advanced TNM stage, positive resection margin, and positive lymph nodes ratio>10%as poor prognostic features (P<0.05). Radiotherapy significantly improved OS and LRFS in patients with IIIA/IIIB disease (P=0.004and0.002, respectively), T3-4disease (P=0.008and0.002, respectively), and positive lymph nodes (P=0.003and0.000, respectively).Conclusions:C-SCLC is a rare type of SCLC with relative more limited stage and better prognosis. Smoking, advanced TNM stage, positive resection margin and positive lymph nodes ratio>10%are poor prognostic factors. Multimodality therapy is recommended. Radiotherapy can benefit the patients with IIIA/IIIB C-SCLC, T3-4disease or positive lymph nodes.