Prognostic significance of the pN classification supplemented by body mass index for esophageal squamous cell carcinoma

BACKGROUND: Body mass index (BMI) has been associated with the risk of esophageal cancer. But the influence of BMI on postoperative complications and prognosis has always been controversial. METHODS: Between 2000 and 2007, 424 patients with esophageal squamous cell carcinoma (ESCC) underwent R0 esophagectomy at our center without neoadjuvant therapy. We performed univariate and multivariate analyses to identify prognostic factors for survival. RESULTS: Patients were divided into three groups according to Asian-specific BMI cut-off value: underweight (n = 45), normal weight (n = 228), and overweight and obese (n = 151). Mean follow-up time was 39 months. The five-year overall survival (OS) rate was 19%, 34%, and 42% for underweight, normal weight, and overweight and obese, respectively (P < 0.001). The five-year disease-free survival (DFS) rate was 24%, 41%, and 74% for underweight, normal weight, and overweight and obese, respectively (P < 0.001). Multivariate analysis showed that pT, pN, and BMI were independent prognostic factors for DFS and OS. The C-index to the combined model showed improved predictive ability when compared to the pN classification (0.779 vs. 0.734). CONCLUSION: Preoperative BMI was an independent prognostic factor for OS and DFS. The proposed new prognostic model with the pN classification supplemented by BMI might improve the ability to discriminate ESCC patients' outcome.