The role of MRI in predicting Ki-67 in breast cancer: preliminary results from a prospective study.

Purpose: In the last decade contrast-enhanced magnetic resonance imaging (MRI) has gained a growing role as a complementary tool for breast cancer diagnosis. Currently the relationship between the kinetic features of a breast lesion and pathologic prognostic factors has become a popular field of research. Our aim is to verify whether breast MRI could be considered a useful tool to predict Ki-67 score, thus resulting as a breast cancer prognosis indicator. Methods: From June to December 2014, we enrolled patients with breast cancer who underwent preoperative dynamic contrast-enhanced MRI at the local health agency. We analyzed the time-signal intensity curves calculating the mean values of the following parameters: the basal enhancement (E-base), the enhancement ratio (ENHratio), the maximum enhancement (E-max), and the steepest slope of the contrast enhancement curve (S-max). Scatterplots and Pearson correlation test were used to investigate the eventual associations among these parameters. Results: A total of 27 patients underwent breast MRI during the study period. The mean +/- SD Ki-67 percentage was 27.03 +/- 16.8; the mean E-max, S-max, E-base, and ENHratio were 433.9 +/- 120.2, 267.3 +/- 96.8, 165.5 +/- 77.1, and 187.1 +/- 94.8, respectively. Scatterplots suggest a positive correlation between Ki-67 and both E-max and S-max. The correlation tests between Ki-67 and E-max, Ki-67 and S-max showed statistical significance. Conclusions: Our preliminary data suggest that enhancement pattern is closely linked to breast cancer proliferation, thus proving the relationship between more proliferating tumors and more rapidly enhanced lesions. This is hypothesis-generating for further studies aimed at promoting breast MRI in the early estimation of cancer prognosis and tumor in vivo response to chemotherapy.