Clinical, pathological and treatment factors associated with the survival of patients with pulmonary sarcomatoid carcinoma.

Pulmonary sarcomatoid carcinoma (PSC) is a group of five rare non-small cell lung cancer subtypes. In the present study, the clinical characteristics and outcomes of patients with PSC registered in the Surveillance, Epidemiology and End Results (SEER) database were investigated. For this purpose, data for patients with PSC (n=1,723) who received their initial diagnosis between 1988 and 2016 were collected from the SEER database. Survival analysis was performed using the Kaplan-Meier curves and the log-rank test. Subsequently, multivariate analyses with the Cox proportional hazards model were used to identify significant independent predictors. A nomogram model was established to predict survival performance using the concordance index (C-index). From the total cohort, patients with pulmonary blastoma demonstrated improved 1-year overall survival (OS) rate compared with other pathological types (P<0.001). The 2-year overall survival rates of the 'only radiotherapy' cohort and the 'no specific treatment' cohort were 9.1 and 5.4% (P<0.001), respectively. Radiotherapy significantly improved the OS rate in stage I-III patients with PSC (P<0.001) when stratified by stage. After matching the propensity scores, the 'surgery combined with radiotherapy' group comprised 156 patients and the 'surgery-only' group had 247 patients (1:1.6). However, no significant differences in prognosis were found between the 2 subgroups (P=0.052). The multivariate Cox analysis demonstrated that older age (≥76 years old), male, unmarried, pathological type, larger tumor size (≥56 mm), later tumor node metastasis stages and treatment modalities were independent prognostic factors. A nomogram model was established to predict the survival of patients with PSC. This model incorporated the seven aforementioned independent prognostic factors (C-index for survival, 0.75; 95% confidence interval, 0.74-0.76). Radiotherapy needs to considered for stage I-III patients with PSC who undergo radiation therapy without surgical resection.