LAUSR

and 30.7% (n = 70) received both surgery and CT. Despite the very small sample size, CT did not significantly improve postoperative survival (P = 0.054). A total of 26 patients received postoperative radiation and CT; however, we observed that patients administered postoperative radiation, and CT showed no improved OS (P = 0.592). Totally 61% (n = 296) of patients had unresectable disease (Table 1). Totally 37 patients were treated with chemoradiotherapy, 177 underwent single-agent CT, and 77 were observed. Median OS was markedly prolonged in cases who received chemoradiotherapy compared with the CT and no-treatment groups, with OS times of 16, 9, and 2 months, respectively (P = 0.02). We additionally performed a subgroup analysis of OS in the 3 treatment groups based on the TNM stage. Interestingly, patients treated with chemoradiotherapy had significantly longer OS in patients with T1 and T2 stage tumors (27 vs 4 vs 8months,P = 0.000). Furthermore, chemoradiotherapy significantly increased survival in individuals with T3 and T4 stage tumors (15 vs 9 vs 2 months, P = 0.000). Totally 485 cases with known prognosis were assessed in multivariable and univariable analyses. Univariable analysis indicated that age, TNM staging, surgery, radiation therapy, tumor size, LNmetastasis, and metastatic disease were significantly associated with OS. Next, the multivariable analysis revealed that age, primary site surgery, radiation therapy, tumor size, LN metastasis, and metastatic disease were independent prognostic factors. In conclusion, this study suggests that surgical resection of the primary tumor prolongs the survival of poorly differentiated and undifferentiated pNEC patients. In addition, unresectable cases selected for chemoradiotherapy had higher OS than those without chemoradiotherapy.