Statistical analysis
All statistical analyses were performed using SPSS software (version
21.0; IBM for Windows, Armonk, NY, USA). Categorical variables were
analysed using the chi-square test
(or Continuity correction chi-square test or
Fisher’s exact test). The stepwise
multivariate Logistic model using the forward Wald method was used to
determine independent impact factors for lymph node metastasis.
<0.05 was considered statistically significant.