Analysis On Significance And Prognostic Factors Of Adjuvant Chemotherapy After Neoadjuvant Chemotherapy For Locally Advanced Thoracic Esophageal Cancer

Purpose: This study aims to compare the long-term survival rates and analyze the prognostic factors for four different therapeutic methods on esophageal squamous carcinoma at locally advanced stage: 1)neoadjuvant and adjuvant chemotherapy,2)neoadjuvant chemotherapy,3)adjuvant chemotherapy and 4)surgery alone,and to provide a theoretical basis for effective treatment for esophageal squamous cell carcinoma.Methods: This study collected the data of the patients with stage T2N1-3M0 and T3-4N0-3M0 thoracic esophageal squamous cell carcinoma who underwent a radical surgery from January 2006 to January 2016.Neoadjuvant and adjuvant group was used as the benchmark group to perform propensity score matching analysis at the ratio 1:1:3:3 with neoadjuvant chemotherapy group,Adjuvant chemotherapy group and surgery alone group.After matching,there were 43 patients in sneoadjuvant and adjuvant group and neoadjuvant chemotherapy group,respectively,120 patients in adjuvant cemotherapy group,and 125 patients in surgery alone group.The univariate analysis was completed by Kaplan-Meier method,and tested by Log-rank method.Cox regression model was used for multivariate analysis.Results: The follow-up was carried out until January 2021.A total of 331 patients were included in this study with one-year overall survival rate of85.5%,three-year survival rate,53.5%,and five-year survival rate,41.7%,and the median survival time was 41 months(ranged from 3 to 181 months).The univariate analysis indicated that four factors had a statistically significant impact on the overall survival rate including gender,the number of positive lymph nodes,therapy methods and vessel or nerve invasion.The multivariate analysis showed that tumor location,therapy methods,depth of tumor invasion and the number of positive lymph nodes were independent prognostic factors(P<0.05).Meanwhile,the univariate analysis also indicated that four factors had statistically different effects on the disease-free survival(DFS)including gender,the number of positive lymph nodes,therapeutic methods and vessel or nerve invasion.The survival rate varied with therapeutic methods: neoadjuvant and adjuvant group was higher than neoadjuvant chemotherapy group and surgery alone group(P<0.05),and adjuvant chemotherapy group was higher surgery group(P<0.05).The disease-free survival of adjuvant chemo-therapy group was higher than that of neoadjuvant chemotherapy group,(P<0.05).Conclusions:1.For patients with locally advanced thoracic esophageal squamous cell carcinoma,n CT-surgery-AC is the best treatment model.2.Gender difference is an independent prognostic factor that affects the treatment.Overall survival(OS)and disease-free survival(DFS)in females are higher than those in males.3.Tumor location has a significant impact on the long-term survival rate.The prognosis for esophageal squamous carcinoma in lower thoracic segment is the best,followed by middle thoracic segment,and that for upper thoracic segment is the worst.4.The number of positive lymph nodes and the depth of tumor invasion are the independent factors affecting the prognosis.