RECIST for Response (Clinical and Imaging) in Neoadjuvant Clinical Trials in Operable Breast Cancer.

Although approximately 70% of breast cancer patients demonstrate a clinical response on neoadjuvant systemic therapy on physical examination or on anatomic radiographic imaging, only 3%-40% achieve a pathologic complete response (pCR). Magnetic resonance imaging (MRI) is superior to physical examination, ultrasound, and mammography in response evaluation during neoadjuvant systemic therapy. The accuracy of breast MRI to predict pCR has a moderate sensitivity, but high specificity. The accuracy of anatomic imaging to assess residual disease and predict pCR depended on anatomic radiographic imaging cancer subtypes. Response monitoring using breast is accurate in triple-negative or HER2-positive tumors. It was inaccurate in estrogen receptor-positive/HER2-negative subtype. Another approach currently under investigation is dynamic contrast-enhanced MRI and diffusion weighted-imaging, (18)F-fluorodeoxyglucose positron emission tomography, fluorodeoxyglucose positron emission tomography/computed tomography.