One-Week radiation for breast cancer lymph nodes could be as effective as three weeks

This study compares a one-week ultra-hypofractionated radiation regimen (26 Gy in 5 fractions) to the standard three-week moderate hypofractionated regimen (40 Gy in 15 fractions) for treating lymph nodes after breast cancer surgery. The goal is to see if the shorter course is just as effective at preventing cancer recurrence while reducing treatment burden. About 1,950 participants will be enrolled to evaluate safety and outcomes.