To investigate whether the additional induction chemotherapy (IC) to concurrent chemoradiotherapy (CCRT) was able to improve overall survival (OS) and disease-free survival (DFS), and to clarify if stage-specified chemoradiotherapy regimens benefit the most for locoregionally advanced NPC.

Data of patients firstly diagnosed NPC from Jan 1st, 1998 to Jun 1st, 2013 were downloaded from Department of Medical Information, Sun Yat-Sen University Cancer Center. Patients were excluded if they had stage I or II disease, no complete medical records, received treatment previously, or without concurrent chemoradiotherapy. Follow-up data is updated on October 1st, 2015.The propensity score-matching (PSM) method was adopted to balance observed covariates between both groups. Propensity scores reflect the conditional probability that is intended to be uniform between patients received CCRT and IC+CCRT based on their baseline characteristics. Matching was performed based on nearest-neighbor matching, and comparing between CCRT and IC+CCRT patients were matched within their respective risk groups.

Inclusion Criteria:

1. firstly diagnosed NPC in SYSUCC from Jan 1st, 1998 to Jun 1st, 2013;
2. with complete medical records;
3. received radical RT.

Exclusion Criteria:

1. distant metastasis patients at first diagnosis,
2. recurrent patients,
3. not finishing radiotherapy, missing medical data, death during RT, stage I or II disease,received treatment previously, or without concurrent chemoradiotherapy were excluded.

firstly diagnosed NPC in SYSUCC from Jan 1st, 1998 to Jun 1st, 2013