Low body mass index is associated with poor treatment outcome following radiotherapy in esophageal squamous cell carcinoma

PURPOSE: We aimed to determine whether patients with esophageal cancer with a low baseline body mass index (BMI) have a poor prognosis following radiotherapy (RT). MATERIALS AND METHODS: We retrospectively analyzed data from 50 patients with esophageal cancer to determine whether a low starting BMI (before RT) was associated with a poor outcome. All study participants were diagnosed with non-metastatic esophageal squamous cell carcinoma (SCC). RESULTS: The number of patients at each T stage were as follows: 7 (14%) patients at T1, 18 (36%) at T2, 19 (38%) at T3, and 6 (12%) at T4. Based on BMI, 7 (14%) patients were defined as underweight. A low BMI was common in patients with T3/T4 stage esophageal cancer (7/43, p = 0.01). Overall, the 3-year progression-free survival (PFS) and overall survival (OS) rates were 26.3% and 69.2%, respectively. In univariate analysis, clinical factors associated with poor PFS included being underweight (BMI <18.5 kg/m2; p = 0.011) and a positive N status (p = 0.017). Univariate analysis also revealed that being underweight was associated with a decrease in OS (p = 0.003). However, being underweight was not an independent prognostic factor for PFS and OS. CONCLUSION: Patients with esophageal SCC with a low starting BMI (BMI <18.5 kg/m2) are more prone to have a negative survival outcome following RT than patients who are considered to be normal weight or overweight. For this reason, it is important that clinicians pay more attention to BMI when treating patients with esophageal SCC.