Patterns of regional recurrence according to molecular subtype in patients with pN2 breast cancer treated with limited field regional irradiation.

In patients with pN2 breast cancer, the risk of regional recurrence was higher in the triple-negative and HER2-type than in the luminal type. In-field recurrence was predominant in triple-negative cancer, while out-field recurrence was frequent in luminal and HER2-type breast cancers.