Statistical analysis
According to previous reports and the results of our pre-experiments, we calculated that a sample of 118 patients (59 in regular group; 59 in prolonged group) would provide the study with 80% power to detect a difference between the group proportions of 20% at a two-sided alpha of 0.05. Given an anticipated dropout rate of 20%, total sample size required is 148 (74 in regular group 1; 74 in prolonged group).Statistical analysis was performed using SPSS software (version 22; SPSS, Inc). Measurement data were expressed as mean ± standard deviation (SD) and were analyzed with t test. Response rates were compared using the chi-square or Fisher’s exact tests. All statistical tests were two-sided, with significance levels at 