Objective To investigate the clinical characteristics and prognostic factors of the limited-stage disease (LD) and extensive-stage disease (ED) of primary esophageal small cell carcinoma (PESCC).

Methods The clinical data and follow-up information of 72 patients with PESCC were retrospectively analyzed. Chi-square test was used to compare the baseline data of patients with LD and ED, Kaplan-Meier method was employed to draw the survival curve of both groups, and Log-rank test was employed to compare survival rates between groups. Univariate and multivariate Cox regression methods were used to analyze the factors affecting the overall survival (OS) of patients with LD and ED.

Results A total of 49 patients with LD and 23 patients with ED were included in this study. The median survival time of patients with LD was 18.300 months and that of patients with ED was 10.903 months (P=0.029). Total protein (TP) value (HR=0.890, 95%CI: 0.805−0.983, P=0.022) and chemotherapy cycle number (HR=0.388, 95%CI: 0.187−0.807, P=0.011) were independent prognostic factors of patients with LD. Systemic immune-inflammation index (SII) (HR=1.002, 95%CI: 1.000−1.004, P=0.007) and C-reactive protein (CRP) (HR=1.065, 95%CI: 1.021−1.111, P=0.004) were independent prognostic factors of patients with ED.

Conclusion The malignant degree of PESCC is high, and prognosis is poor. Patients with LD and ED have different prognostic factors. Total protein value and chemotherapy cycle are independent prognostic factors of patients with LD. SII and CRP are independent prognostic factors of patients with ED.