E1283. Assessing and Reporting Response to Neoadjuvant Chemotherapy: A Primer For Breast Radiologists
  1. Haydee Ojeda-Fournier; UC San Diego Health
  2. Clair Meriwether; UC San Diego Health
  3. Alexandra Hasen; No Affiliation
  4. Rebecca Rakow-Penner; UC San Diego Health
  5. Souda Fazeli; UC San Diego Health
  6. Mohammad Eghtedari; UC San Diego Health
  7. Vivian Lim; UC San Diego Health
Breast cancer may be treated with chemotherapy before surgical management. The goals of neoadjuvant chemotherapy (NAC) are to decrease the size of a tumor to allow breast conservation, assess response of tumor in vivo to tailor chemotherapy regiments if needed, convert non-operable breast cancer (for example, those invading the chest wall) to an operable case, and predict overall survival. Breast MRI is the most accurate imaging modality to assess response to chemotherapy. Evaluating the response in the axilla is also crucial for oncologic, surgical, and radiation therapy planning.

Educational Goals / Teaching Points
At the end of this educational exhibit, the learner will recognize the indications for NAC; compare the types of response to NAC and their appearances, and know the different molecular types of breast cancer and their expected response to NAC. Breast MRI is the most accurate imaging modality to assess response to neoadjuvant chemotherapy. molecular subtypes of breast cancers have different responses to NAC, and an organized and consistent imaging report is needed to facilitate clinical management of NAC.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Imaging response to NAC is classified as complete response, partial response, no response, or progression of disease. The accuracy of MRI varies depending on the histologic subtype of cancer, with the highest accuracy for triple-negative breast cancer and the lowest for luminal tumors. In addition to assessing response to the breast tumor, response to axillary nodal disease, if present, is also crucial for oncologic management and surgical and radiation therapy planning.

MRI is more accurate than ultrasound, mammography, and clinical examination in assessing response to NAC, predicting recurrence-free survival, and estimating complete pathologic response in patients with breast cancer.