Takayoshi Uematsu MD, Presenter: Nothing to Disclose

Masako Kasami, Abstract Co-Author: Nothing to Disclose

To retrospectively evaluate the magnetic resonance (MR) imaging findings of breast cancer before neoadjuvant chemotherapy (NAC) and to compare those of chemosensitive breast cancer with those of chemoresistant breast cancer.

The MR imaging findings before NAC in 120 women undergoing NAC were reviewed. MR imaging findings included tumor shape, margin, internal enhancement, and size, as well as intratumoral signal intensity that was stronger than or almost the same as that of water or vessels on T2-weighted MR images. The MR imaging findings were compared with the pathological findings and responses.

Of 120 breast cancers in 120 women, pathologically complete response and marked response were achieved 12% (14/120) and 35% (42/120), respectively. Breast cancers with pathologically complete response or marked response were classified as chemosensitive breast cancer. The remaining 64 breast cancers (53%) were classified as chemoresistant breast cancer. Large tumor size (P=.029), severe lymphatic invasion (P=0.003), nonmass lesion type (P =.014), and very high intratumoral signal intensity on T2-weighted MR images (P =.002) were significantly associated with chemoresistant breast cancer. Invasive ductal carcinoma (P=.028) and washout enhancement pattern (P =.034) were significantly associated with chemosensitive breast cancer. Areas with very high intratumoral signal intensity on T2-weighted images corresponded pathologically to areas of intratumoral necrosis.

Several MR imaging features before NAC might be useful for predicting the efficacy of NAC.

Breast MR imaging before NAC may be an effective noninvasive imaging technique for predicting pathologically complete response and marked response.

Uematsu, T, Kasami, M, Neoadjuvant Chemotherapy for Breast Cancer: Correlation between MR Imaging Findings and Pathological Responses.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8008304.html