Breast-Conserving Surgery with or without Irradiation in Early Breast Cancer (PRIME II)

For most older women with early breast cancer, standard treatment after breast-conserving surgery is whole-breast radiotherapy and endocrine treatment. Numerous randomised trials have confirmed that radiotherapy after breast conservation reduces the rate of local recurrence substantially and may have a small long-term (15-year) benefit on survival on meta-analysis of these trials. ¹ The PRIME II trial aimed to assess the effect of omission of radiotherapy on local control in older women at low risk of local recurrence.