Prognostic Relevance of Change in Body Mass Index in Patients With Nasopharyngeal Carcinoma Undergoing Volumetric Modulated Arc Therapy: A Retrospective Study

OBJECTIVE: To assess the effect of pretreatment body mass index (BMI) and the extent of change in BMI (ΔBMI) during the treatment course on the treatment outcomes in patients with nasopharyngeal carcinoma (NPC) receiving volumetric modulated arc therapy (VMAT). METHODS: Data pertaining to 498 consecutive NPC patients with stage I–IVA disease who received VMAT between January 2010 and November 2011 at a single center were retrospectively analyzed. Univariate Kaplan-Meier and multivariate Cox regression analyses were used to evaluate the prognostic significance of pretreatment BMI and ΔBMI. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off point of ΔBMI. RESULTS: The 5-year loco-regional failure-free (L-FFR), distant failure-free survival (D-FFR), disease-free survival (DFS), and overall survival (OS) rates were 90.6%, 83.7%, 71.5% and 79.3%, respectively. The 5-year L-FFR, D-FFR, DFS, OS rates for NPC patients with ΔBMI ≤1 kg/m(2) vs ΔBMI >1 kg/m(2) were 92.3% vs 89.3% (P = .137), 90.9% vs 78.5% (P < .001), 80.4% vs 65.1% (P < .001), and 88.0% vs 73.0% (P < .001), respectively. ΔBMI >1 kg/m(2) was an independent predictor of D-FFR (P = .002), DFS (P = .002), and OS (P = .001). CONCLUSIONS: ΔBMI during treatment course may have a significant impact on the prognosis of NPC patients receiving VMAT.