Variation of breast vascular maps at dynamic contrast-enhanced MR imaging after primary chemotherapy of locally advanced breast cancer

OBJECTIVE. The purpose of this article is to assess changes in breast vascular maps on dynamic contrast-enhanced MRI (DCE-MRI) after primary chemotherapy in patients with locally advanced breast cancer (LABC). SUBJECTS AND METHODS. Thirty-four patients with unilateral LABC underwent DCE-MRI before and after anthracycline- and taxane-based primary chemotherapy. The number of vessels 30 mm or longer in length and 2 mm or larger in maximum transverse diameter were counted on maximum intensity projections of the first subtracted phase for each of the two breasts. Patients achieving pathologic response or small clusters of residual cancer cells after primary chemotherapy were considered as responders, and those with an inferior pathologic response were considered as nonresponders. RESULTS. The mean (\ub1 SD) number of vessels in the breast harboring the cancer and in the contralateral breast was 2.7 \ub1 1.3 and 1.1 \ub1 1.0 (p < 0.001), respectively, before primary chemotherapy and 1.3 \ub1 1.1 and 1.1 \ub1 1.1 (p = 0.147), respectively, after primary chemotherapy. Overall, primary chemotherapy was associated with a significant reduction in DCE-MRI vascular maps in the breast harboring the cancer only (p < 0.001). Of the 34 patients, 10 were considered responders and 24 were nonresponders. The mean number of vessels in the breast harboring the cancer changed from 2.7 \ub1 1.1 to 0.6 \ub1 0.8 for the 10 responders and from 2.7 \ub1 1.4 to only 1.6 \ub1 0.9 for the 24 nonresponders. The mean reduction of vascular map in the breast harboring the cancer was significantly higher in responders compared with nonresponders (p = 0.017). CONCLUSION. Before primary chemotherapy, DCE-MRI vascular maps were asymmetrically increased ipsilaterally to the LABC. After primary chemotherapy, vascular maps significantly changed only in the breast harboring the cancer, with significant differences between responders and nonresponders