Analysis of the prognostic factors of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in 220 cases of locally advanced squamous esophageal cancer: a retrospective cohort study

BACKGROUND: Esophageal cancer is one of the most common malignant tumors in China. Patients with advanced esophageal cancer often cannot be treated by surgery; in these cases, radiation therapy is usually applied. However, there are currently few studies on the clinical efficacy of this treatment method. The present study aimed to investigate and observe the clinical efficacy and related prognostic factors of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in esophageal squamous carcinoma, and to provide a reference for clinicians in radiotherapy (RT) departments. METHODS: The clinical and follow-up data of 220 patients with esophageal squamous carcinoma admitted to the First Affiliated Hospital of Bengbu Medical College from January 2017 to December 2018 were retrospectively analyzed to assess the relevant prognostic factors and analyze their effects on 3-year overall survival (OS) and progression-free survival (PFS). The prognostic influencing factors were analyzed using the log-rank test and Cox multi-factor regression analysis. RESULTS: The median follow-up time was 56.0 months (3.0 to 66.0 months). The 1-, 2-, and 3-year survival rates were 68.6%, 49.1%, and 36.3%, respectively, for the entire cohort, and the 1-, 2-, and 3-year PFS rates were 52.3%, 37.7%, and 25.5%, respectively. The median OS time was 24 months [95% confidence interval (CI): 19.16–28.84 months] and the median PFS time was 15 months (95% CI: 11.04–18.96 months). The multifactorial analysis results showed that gender, RT dose, treatment modality, absolute lymphocyte count (ALC), and gross tumor volume (GTV) were independent prognostic factors affecting 3-year OS (P<0.05); while gender, N-stage, RT dose, and GTV were independent prognostic factors affecting 3-year PFS (P<0.05). CONCLUSIONS: In the SIB-IMRT era, the survival of esophageal squamous cell carcinoma (ESCC) patients treated with radical (chemo)radiotherapy is relatively satisfactory. As a single-institution study on radiation therapy for esophageal cancer, this study yielded accurate results that help to provide references for subsequent related studies and clinicians’ selection of treatment options.