Accuracy of OPTIMIST trial criteria on MRI to predict pathologic complete response following neoadjuvant systemic therapy

Motivation: The omission of surgery is gaining attention for breast cancer patients who achieve a pathologic complete response (pCR) following neoadjuvant systemic therapy (NST), emphasizing the need for accurate pre-surgical prediction of NST response. Goal(s): To evaluate whether post-NST radiologic criteria from the OPTIMIST trial reliably predict pCR status. Approach: We retrospectively assessed radiologic criteria (MRI lesion-to-background signal-to-enhancement ratio [SER]≤ 1.6, size≤ 1.0 cm, calcification≤ 2.0 cm) in breast cancer patients treated with NST followed by surgery to determine their association with pCR. Results: The enrollment criteria, especially SER, accurately predicted pCR and is applicable in the clinical setting. Impact: Incorporating the MRI size, SER, and calcification size for accurate pCR prediction supports designing de-escalation trials in good NST responders.