Prognostic value of the tumor volume reduction rate after neoadjuvant chemotherapy in patients with locoregional advanced nasopharyngeal carcinoma.

PURPOSE:Aim of this study was to evaluate the prognostic value of the tumor volume reduction rate (TVRR) of neoadjuvant chemotherapy (NACT) in patients with locoregional advanced nasopharyngeal carcinoma (NPC). METHODS:We collected the clinical data of 263 patients with locoregional advanced NPC receiving NACT and subsequent radiotherapy from two hospitals: a training cohort (n = 130) was obtained from one hospital and a validation cohort was obtained the other hospital (n = 133). By follow-up and calculating the TVRR of all patients, the prognostic value of the TVRR was analyzed though a univariate and multivariate Cox regression model. A cut-off point of the TVRR relating to survival was explored by means of the Youden index, and the prognostic value of the TNM stage plus TVRR was measured by creating receiver operating characteristic (ROC) curves. RESULTS:12.6%, a cut-off point of TVRR, was found to best predict DFS. Patients with a TVRR > 12.6% had better DFS (hazard ratio, 0.160, 95% confidence interval 0.072-0.354; P < 0.001), LRRFS (0.064, 0.013-0.310; 0.001) and DMFS (0.274, 0.106-0.711; 0.008) than patients with a TVRR ≤ 12.6%. The TVRR was a significant independent prognostic factor for OS, DFS, LRRFS and DMFS. Combining the TVRR and TNM stage enhanced the ability to predict DFS and LRRFS. CONCLUSIONS:The TVRR of NACT is an independent prognostic factor for patients with locoregional advanced NPC receiving radiotherapy. Adding the TVRR to the original TNM staging system improves the prognostic value for locoregional advanced NPC.