Statistical analysis
DISEASE
With a two-sided type Ι error of 0.05 and a power of 80%, we calculated that 252 pts were needed in each treatment group to enable the detection of non-inferiority of neoadjuvant FEC3-D3 compared to AC4-D4 with a pCR rate of 20% (non-inferiority margin of 10%). Considering a dropout rate of 10%, and 280 pts in each arm, a total of 560 patients per arm would be enrolled. Pts were randomized using the stratified block randomization method with the hormone receptor and HER2 expression status included as the stratification factors. The sample size was amended due to slower enrolment and competing trials. The revised statistical procedure was that all parameters would be analyzed using descriptive statistics. Disease free survival was calculated with the Kaplan–Meier method. Categorical variables were expressed as proportions and continuous variables as the mean ± SD. The Mann–Whitney U-test was used to compare differences between the treatment arms. The Friedman test was used to detect repeated measurement difference. Statistical analysis was done using SPSS version 23.0 (IBM Corp, Armonk, NY), and statistical significance was defined as a 