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 (DeltaBMI) 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 DeltaBMI. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off point of DeltaBMI. 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 DeltaBMI </=1 kg/m(2) vs DeltaBMI >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. DeltaBMI >1 kg/m(2) was an independent predictor of D-FFR (P = .002), DFS (P = .002), and OS (P = .001). CONCLUSIONS: DeltaBMI during treatment course may have a significant impact on the prognosis of NPC patients receiving VMAT.