Complete Breast MRI Response to Neoadjuvant Chemotherapy and Prediction of Pathologic Complete Response

Area of Science:

• Oncology
• Radiology
• Breast Cancer Research

Background:

• Neoadjuvant chemotherapy (NAC) is a standard treatment for invasive breast cancer.
• Assessing treatment response with imaging is crucial for guiding further management.
• Breast MRI is utilized to evaluate tumor response after NAC.

Purpose of the Study:

• To determine the negative predictive value (NPV) of breast MRI in identifying residual invasive breast cancer after NAC.
• To analyze the NPV of breast MRI across different molecular subtypes of breast cancer.

Main Methods:

• Retrospective study of 244 patients with invasive breast cancer treated with NAC.
• Complete MRI response defined as absence of residual enhancement post-NAC.
• NPV calculated as the proportion of true negatives among complete MRI responders, correlating with pathologic complete response (pCR).

Main Results:

• 16% of patients achieved complete MRI response; 53% of these had a pCR.
• Overall NPV was insufficient to obviate surgical excision.
• NPVs varied significantly by subtype: HR+/HER2- (20%), HR+/HER2+ (30%), HR-/HER+ (75%), and triple-negative (TN) (90%).

Conclusions:

• Complete MRI response after NAC has a 53% pCR rate, indicating limited utility to avoid surgery.
• Breast MRI offers prognostic value for specific molecular subtypes.
• Triple-negative breast cancer demonstrates the highest NPV, suggesting MRI may be more reliable in this subgroup.