Statistical analyses
Categorical variables were compared using χ2 tests or Fisher’s exact tests. OS, PFS, DMFS and LRPFS were compared using the Kaplan–Meier method with log-rank test. Cox regression analysis was used to estimate hazard ratios (HR) and 95% confidence interval (CI). Variables with aP <0.10 in univariate analyses were included in a multivariate analysis. Variables analyzed in our univariate analysis study included gender (male vs female), age (<56y vs ≥56), treatment modality (IC+CCRT vs IC+RT), smoking (no vs yes), alcohol consumption (no vs yes), T stage (T1-2 vs T3-4), N stage (N0-2 vs N3), overall stage (III/IVA vs IVB), modality of IC (PF/TP vs TPF), cycle of IC treatment (≤2 vs >2), and toxicities during treatment (<3 grade vs ≥3 grade).
The SPSS Statistics for Windows, version 24.0 (IBM, Chicago, IL), was used for statistical analysis. All statistical tests were based on a two-sided significance level, and P -values of <0.05, were considered indicative of a statistically significant finding.