High BMI has no impact on the survival of Chinese patients with lower thoracic esophageal adenocarcinoma treated with curative esophagectomy: a propensity score-matched study

Controversy still exists as to whether a high body mass index (BMI) has any impact on the long-term survival of esophageal cancer patients treated with curative esophagectomy. Therefore, we conducted this propensity score-matched (PSM) study to explore the prognostic value of high BMI in Chinese patients with lower thoracic esophageal adenocarcinoma for the first time. We retrospectively collected data of patients with lower thoracic esophageal adenocarcinoma who underwent curative esophagectomy in our department from January 2009 to December 2016. Patients were grouped into high BMI group (≥23 kg/m2) and normal BMI group (18.5-22.9 kg/m2) according to the Asian specific BMI cutoff value. Both Cox regression survival analysis and PSM analysis were applied. Finally, a total of 132 patients were included for analysis. Fifty-three patients were in the high BMI group while 79 patients were in the normal BMI group. There was no significant difference regarding age, gender, comorbidity, tumor differentiation, tumor site, lymphovascular invasion, or surgical approaches between the two groups. However, patients with a high BMI tended to have more stage III diseases but a lower rate of adjuvant therapy application than those with a normal BMI. For survival, there was no significant survival difference between patients with a high BMI and those with a normal BMI (5-year overall survival (OS): 40.8% vs. 48.1%; P = 0.398). In the multivariate analysis, high BMI was not found to be an independent prognostic factor (HR = 1.028, 95%CI: 0.621-1.667, P = 0.945). A total of 92 well-matched patients were included after PSM analysis. However, there was still no significant difference of survival between the two groups (5-year OS: 41.4% vs. 43.3%; P = 0.760). Therefore, high BMI has no impact on survival of Chinese patients with lower thoracic esophageal adenocarcinoma treated with curative esophagectomy.