Highlights
– The SUPREMO randomized phase 3 trial (n≈1607) compared chest‑wall irradiation versus omission after mastectomy in intermediate‑risk breast cancer and found no improvement in 10‑year overall survival (OS).
– Chest‑wall irradiation halved the hazard of local (chest‑wall) recurrence (absolute difference <2%) but produced no meaningful difference in disease‑free survival or distant metastasis‑free survival at 10 years.
