Predictive Clinicopathologic and Dynamic Contrast-Enhanced MRI Findings for Tumor Response to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer.

OBJECTIVE: The purpose of this study is to investigate whether clinicopathologic factors and dynamic contrast-enhanced MRI (DCE-MRI) features are associated with pathologic tumor response to neoadjuvant chemotherapy (NAC) in patients with triple-negative breast cancer (TNBC).

MATERIALS AND METHODS: Seventy-three patients with TNBC who underwent pre-NAC MRI, completed NAC, and underwent surgery between January 2009 and December 2010 were included in the study. MRI features and clinicopathologic factors for predicting pathologic responses were analyzed, and residual tumor sizes, as measured using MRI and surgical specimens, were evaluated.

RESULTS: Of 73 study patients, 20 (27%) had a pathologic complete response (pCR). Homogeneous enhancement on pre-NAC MRI (odds ratio from multivariate analysis, 14.66) and a concentric shrinkage pattern of tumor volume reduction on post-NAC MRI (odds ratio, 8.63) were independently associated with pCR. Residual tumor sizes, as measured using MRI and surgical specimens, showed a strong correlation (r = 0.652, p < 0.001). The correlation for residual tumor sizes was stronger for patients with pCR (r = 0.600, p < 0.001) and those with a concentric shrinkage pattern (r = 0.818, p < 0.001) than for patients with a response other than near pCR or pCR (i.e., the non-pCR group) (r = -0.128, p = 0.590) and patients with a dendritic shrinkage pattern of tumor volume reduction (r = 0.270, p = 0.182).

CONCLUSION: Homogeneous enhancement of tumors on pre-NAC MRI and the presence of a concentric shrinkage pattern after NAC are associated with pCR in patients with TNBC. Residual tumor sizes on MRI and surgical specimens tended to show a stronger correlation in the pCR group or the concentric shrinkage group than in the non-pCR group or the dendritic shrinkage group.