Primary endpoint and power calculation For the ablative cohort: the expected 2-year PFS is 20% in the control arm (arm A) and 40% in the experimental arm ( arm B). The study is therefore powered to test for a difference in PFS at 2 years of 20%. The null hypothesis (H0) is that there is no difference in PFS between arm A and arm B. This results in a sample size of 72 patients evenly divided over two arms with 36 patient per arm. Considering a dropout rate of 10% from current experience, the actual amount of patients will be 40 per arm or 80 in total.