Study design and randomization
The primary endpoint was the cumulative incidence of patients experiencing symptomatic RN (grade 2–4). A superiority design was assumed. Symptomatic RN was expected at around 10% at one year for Arm-A. Considering a rate of ~ 1% for Arm-B, 250 patients were required for the study to have a power of 80% to demonstrate this difference with a two-sided 