21-Gene recurrence score predictive for prognostic benefit of radiotherapy in patients age ≥ 70 with T1N0 ER/PR + HER2- breast cancer treated with breast conserving surgery and endocrine therapy

•In modern practice, patients age ≥70 with T1N0 ER/PR + HER2- breast cancer who are treated with breast conserving surgery and endocrine therapy have been considered candidates for omission of radiotherapy.•Recurrence score (RS) is predictive for prognostic benefit of radiotherapy in patients age ≥70 years.•There is an overall survival benefit with the use of radiotherapy in patients with RS ≥11 but not in patients with RS < 11.•Assessment of RS in patients age ≥70 years is recommended with consideration of RT when RS is ≥11.