Prognostic factors and treatment strategies of limited-stage primary esophageal small-cell carcinoma-a SEER database analysis.

Background: Primary esophageal small-cell carcinoma (PESC) is a rare tumor with poor efficacy, and there is currently no standardized treatment method. Our aim is to explore the prognostic factors and possible optimal treatment modalities for limited-stage PESC. Methods: We retrospectively searched the Surveillance, Epidemiology, and End Results (SEER) database from 1975 to 2019 for data of patients with limited-stage PESC. Kaplan-Meier method was used to plot survival curves, calculate survival rates, and Log-rank was used to test the differences among survival curves. Prognostic factors were explored through univariate and multivariate Cox regression survival analyses; Cox regression survival analysis was also conducted to analyze the risk of death among treatment groups and compare the survival differences among each treatment group. The non-single treatment (ST) group was defined as the comprehensive treatment (CT) group and it was compared against the ST group. Results: A total of 186 cases of limited-stage PESC were included in the study, there were differences in survival time among different groups due to differences in age, year, median household income, and N stage (P<0.001, P=0.041, P=0.002, P=0.001). The median overall survival (mOS) of the surgical group (19 months) was longer than that of the nonsurgical group (11 months) (P=0.01). The mOS of the chemotherapy group (16 months) was longer than that of the non-chemotherapy group (4 months) (P<0.001). The mOS of the radiotherapy group (16 months) was longer than that of the non-radiotherapy group (8 months) (P<0.001). Univariate analysis showed that age ≥80 years (P=0.006), year (1997-2007) (P=0.01), year (2008-2019) (P=0.01), N2 (P=0.003), surgery (P=0.02), radiotherapy (P<0.001), and chemotherapy (P<0.001) were prognostic factors affecting overall survival (OS) in limited-stage PESC patients. Multivariate analysis showed that SEER stage (P=0.02), age (P=0.007), radiotherapy (P<0.001), surgery (P=0.006), and chemotherapy (P<0.001) were independent prognostic factors affecting OS in patients of limited-stage PESC. Prognosis was better in the non-monotherapy group than in each monotherapy group. The CT group is superior to the ST group (P<0.001). The surgery combined with chemotherapy (SC) group had the longest mOS and the highest reduced risk of death, but there was no statistical difference. Conclusions: SEER stage, age, radiotherapy, chemotherapy, and surgery were independent prognostic factors in limited-stage patients; CT outperformed ST; the SC group had the longest median survival, but showed no statistical difference.