Development and validation of a genomic profile for the omission of local adjuvant radiation in breast cancer

Adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) for invasive breast cancer is effective at reducing locoregional recurrence (LRR). Although most patients will not experience LRR even without RT, tools to guide selection of patients who can safely omit RT are lacking. Analysis of two randomized trials of BCS with or without RT resulted in development and validation of the 16-gene signature POLAR (‘Profile for the Omission of Local Adjuvant Radiation’), identifying patients with ER-positive, HER2-negative early breast cancer with low LRR risk who can safely avoid RT after BCS, and high risk patients with significant benefit from RT.