Clinical outcomes of surgically resected combined small cell lung cancer: a two-institutional experience.

BACKGROUND:The combined small cell lung cancer (c-SCLC) was rare and its clinicopathological characteristics had not been thoroughly described. The aim of this study was to determine prognostic factors and survival in c-SCLC patients. METHODS:Clinical records of patients with c-SCLC who underwent surgery between January 2009 and December 2013 in two institutions were retrospectively reviewed. RESULTS:Ninety-seven patients were identified. The most common pathology was combined SCLC and large cell neuroendocrine carcinoma (LCNEC, N=46), followed by combined SCLC and squamous cell carcinoma (SCC) (N=32), combined SCLC and adenocarcinoma (AC) (N=12), and combined SCLC and adenosquamous carcinoma (ASC) (N=7). The overall survival (OS) rates of the entire cohort were 42.4% and 35.2% at 3 and 5 years, respectively. Multivariate analysis identified sex [female vs. male, hazards ratio (HR) =0.38; 95% confidence interval (CI): 0.19-0.79; P=0.010], age (<53 vs. >53 years, HR =0.28; 95% CI: 0.09-0.81; P=0.019), performance status (<2 vs. >2, HR =0.08; 95% CI: 0.02-0.32; P<0.001), combined non-small cell lung cancer (NSCLC) components (LCNEC vs. non-LCNEC, HR =3.00; 95% CI: 1.03-8.76; P=0.045), adjuvant therapy (yes vs. no, HR =0.33; 95% CI: 0.17-0.67; P=0.002) as significantly prognostic factors of OS in patients with complete resection and lymphadenectomy. CONCLUSIONS:The mixed NSCLC components within c-SCLCs had a significant influence on the survival. Compared with surgery alone, adjuvant therapy was associated with significantly improved survival in patients with complete resection and lymphadenectomy.