Early response by MR imaging and ultrasound as predictor of pathologic complete response to 12-week neoadjuvant therapy for different early breast cancer subtypes : Combined analysis from the WSG ADAPT subtrials

We evaluated the role of early response after 3 weeks of neoadjuvant treatment (NAT) assessed by ultrasound (US), magnetic resonance imaging (MRI) and Ki‐67 dynamics for prediction of pathologic complete response (pCR) in different early breast cancer subtypes. Patients with HR+/HER2+, HR−/HER2− and HR−/HER2+ tumors enrolled into three neoadjuvant WSG ADAPT subtrials underwent US, MRI and Ki‐67 assessment at diagnosis and after 3 weeks of NAT. Early response was defined as complete or partial response (US, MRI) and ≥30% proliferation decrease or

What's new? In breast cancer, a pathologic complete response (pCR) after neoadjuvant therapy (NAT) can predict long‐term outcome. However, rates of pCR differ according to EBC subtype. So what is the most useful approach to determine early response? In this prospective study, the authors compared MRI, ultrasound, and Ki‐67 status after three weeks of NAT. They found that MRI and Ki‐67 had higher sensitivity than ultrasound in HR‐/HER2+ and HR‐/HER2‐ tumors, while all three methods were similar for HR+/HER2+ tumors. These findings could guide identification of candidates for therapy de‐escalation or escalation.