Spss release ver 18

The OS and DFS were determined through the Kaplan- Meier method and compared using the log-rank test. The Cox proportional hazards model was used in a multivariate analysis to estimate the hazard ratio and to adjust the potential confounding effects. The factors found to be significant on an univariate analysis or thought to be clinically important were subjected to a multivariate analysis. p < 0.05 was considered statistically significant. Data were analyzed using SPSS release ver. 18.0.1 (SPSS Inc., Chicago, IL).

OS was calculated from the date of pathologic confirmation. PFS was defined as the time from the date of pathologic confirmation to the date of relapse, progression, or the last date of follow-up. OS and PFS were determined using the Kaplan-Meier method and compared using the log-rank test. The Cox proportional-hazards model was used for multivariate analysis. Pearson’s chi-square test or Fisher’s exact test was used for comparison of the distribution of clinical parameters between two groups. SPSS release ver. 18.0.1 (SPSS Inc., Chicago, IL) was used for statistical analyses. Values of p < 0.05 indicated statistical significance.