Omission of adjuvant radiotherapy in early-stage breast cancer: have we identified a subgroup?

Recognizing the burden, toxicity, and cost associated with adjuvant radiotherapy, investigators have endeavoured to identify a low-risk patient population, in whom the local recurrence risk is sufficiently low, so that radiotherapy can be reasonably omitted. Several randomized trials (1-4) and single-arm studies (5,6) demonstrated unacceptably high local recurrence rates, ranging from mid-teens to high twenties, when patients did not receive adjuvant radiotherapy, even with other favourable features.