Neutropenia during the First Cycle of Induction Chemotherapy Is Prognostic for Poor Survival in Locoregionally Advanced Nasopharyngeal Carcinoma: A Real-World Study in an Endemic Area.

PURPOSE: The purpose of this study was to investigate the effect of neutropenia during the first cycle of induction chemotherapy (IC-1) on survival in locoregionally advanced nasopharyngeal carcinoma (LANPC). MATERIALS AND METHODS: Eligible patients (n=545) with LANPC receiving IC+concurrent chemoradiotherapy were included. Based on nadir neutrophil afterIC-1, all patientswere categorized into three groups: no/grade 1-2/grade 3-4 neutropenia. Five-year overall survival (OS) and disease-free survival (DFS) were compared between groups and subgroups stratified by IC regimen. We also explored the occurrence of IC-1-induced myelosuppression events and the minimal value of post-treatment neutrophil-to-lymphocyte ratio (post-NLRmin). Univariate/multivariate analyses were performed to investigate the effect of IC-1-induced neutropenia, timing of neutropenia, number of myelosuppression events, and high post-NLRmin on OS/DFS. RESULTS: Grade 1-2/grade 3-4 neutropeniawere associatedwith poorer OS/DFS than no neutropenia (all p < 0.05); OS/DFS were not significantly different between patients experiencing grade 1-2 vs. 3-4 neutropenia. Neutropenia had no significant effect on OS/DFS in patients receiving docetaxel-cisplatin-5-fluorouracil (TPF). Grade 1-2 (grade 3-4) neutropenia negatively influenced OS/DFS in patients receiving cisplatin-5-fluorouracil (PF) (PF and docetaxel-cisplatin [TP]; all p < 0.05). Neutropenia, two/three myelosuppression events, and high post-NLRmin (>/= 1.33) was most frequent on days 5-10, second and third week of IC-1, respectively. After adjustment for covariates, IC-1-induced neutropenia, two/three myelosuppression events, and post-NLRmin >/= 1.33were validated as negative predictors of OS/DFS (all p < 0.05); timing of neutropenia had no significant effect. CONCLUSION: Occurrence of neutropenia, number of myelosuppression events, and high post-NLRmin during PF/TP IC-1 have prognostic value for poor survival in LANPC.