Validation of Profile for the Omission of Local Adjuvant Radiotherapy: meta-analysis of three RCTs of breast conserving surgery with or without RT

There are currently no commercially available tests to identify early stage breast cancer patients treated with breast conserving surgery and systemic therapy at low risk of locoregional recurrence (LRR) for whom postoperative radiotherapy (RT) might be safely omitted. POLAR (‘profile for the omission of local adjuvant radiotherapy’) is a 16-gene molecular signature developed to identify these patients. A validation meta-analysis of three randomized controlled trials showed that POLAR is not only prognostic for LRR but also predictive, showing a significant interaction between RT and the classifier. Patients with a high POLAR score should be recommended radiotherapy while patients with a low score may be candidates for omission of radiotherapy after breast conserving surgery.