Statistical analysis Assume 1:1 randomization. The sample size is calculated for the primary efficacy variable, the survival rate. Assuming the survival rate equals to: 90% for group A and 50% for group B. 100 patients in each group are required to yield a 80% chance of detecting such a difference when a two-tailed test is employed at the 0.05 significance levels. Every eligible subject will be assigned with a randomization code and receive one of the two treatments, according to the sequence of enrolled.