The role of radiotherapy in pulmonary large cell neuroendocrine carcinoma: propensity score matching analysis

The aim of the study was to investigate the survival advantage of radiotherapy (RT) in patients with pulmonary large cell neuroendocrine carcinoma (LCNEC). Patients with pulmonary LCNEC were extracted from the Surveillance, Epidemiology, and End Results (SEER) dataset between January 2004 and December 2013. Propensity score matching (PSM) analysis with 1:1 was used to ensure well-balanced characteristics of all comparison groups. A total of 1480 eligible cases were identified, with a median follow-up time of 11 months (0-131 months). After PSM, 980 patients were classified in no radiotherapy (No RT) and radiotherapy (RT) groups (n = 490 each). Patients in the RT group harbored significantly higher 3- and S-year overall survival (OS) and cancer-specific survival (CSS) rates compared to those in the No RT group (both P < 0.05). Furthermore, RT was an independent favorable prognostic factor of OS as well as CSS in multivariate analysis, both before [OS: hazard ratio (HR) 0.840, 95% confidence interval (CI) 0.739-0.954, P = 0.007; CSS: HR 0.847, 95% CI 0.741-0.967, P = 0.014] and after (OS: HR 0.854, 95% CI 0.736-0.970, P = 0.016; CSS: HR 0.848, 95% CI 0.735-0.978, P = 0.023) PSM. In subgroup analysis, American Joint Committee on Cancer (AJCC) stage II and III, tumor size 5-10 cm, patients who underwent no surgery, or patients who received chemotherapy could significantly benefit from RT (all P < 0.05). To sum up, our findings suggested that RT could prolong the survival of patients with pulmonary LCNEC, especially those with stage II and III, tumor size 5-10 cm, those with no surgery, or those who received chemotherapy.