*2.4. Statistical Analysis*

All statistical analyses were performed by using MedCalc Statistical Software version 19.0.7 (MedCalc Software bvba, Ostend, Belgium; https://www.medcalc.org; 2019). Normally and non-normally distributed continuous data were expressed as mean (standard deviation (SD)) and median (interquartile range (IQR)), respectively. Categorical variables were reported as number (%). Overall survival (OS) was defined as the time from the date of pathological diagnosis until the date of death or last follow-up. Disease-free survival (DFS) was defined as the time from the date of pathological diagnosis until the date of recurrence, death, or last follow-up. Survival curves were estimated by using the Kaplan–Meier method. The prognostic factor analyses were performed by log-rank tests and Cox proportional-hazards regression model. Statistical analysis was considered to be significant when the *p*-value was < 0.05.
