Correlation of Perfusion Metrics with Ki-67 Proliferation Index and Axillary Involvement as a Prognostic Marker in Breast Carcinoma Cases: A Dynamic Contrast-Enhanced Perfusion MRI Study

Abstract

Our study aims to reveal clinically helpful prognostic markers using quantitative radiologic data from perfusion magnetic resonance imaging for patients with locally advanced carcinoma, using the Ki-67 index as a surrogate. Patients who received a breast cancer diagnosis and had undergone dynamic contrast-enhanced magnetic resonance imaging of the breast for pretreatment evaluation and follow-up were searched retrospectively. We evaluated the MRI studies for perfusion parameters and various categories and compared them to the Ki-67 index. Axillary involvement was categorized as low (N0-N1) or high (N2-N3) according to clinical stage. A total sum of 60 patients' data was included in this study. Perfusion parameters and Ki-67 showed a significant correlation with the transfer constant (K^trans) (ρ = 0.554 p = 0.00), reverse transfer constant (K^ep) (ρ = 0.454 p = 0.00), and initial area under the gadolinium curve (IAUGC) (ρ = 0.619 p = 0.00). The IAUGC was also significantly different between axillary stage groups (Z = 2.478 p = 0.013). Outside of our primary hypothesis, associations between axillary stage and contrast enhancement (x² = 8.023 p = 0.046) and filling patterns (x² = 8.751 p = 0.013) were detected. In conclusion, these parameters are potential prognostic markers in patients with moderate Ki-67 indices, such as those in our study group. The relationship between axillary status and perfusion parameters also has the potential to determine patients who would benefit from limited axillary dissection.

Keywords: axillary stage; breast cancer; perfusion MRI; prognosis.

Figure 1

Ring-enhancing mass in the left breast. A HER-2-positive tumor, Ki-67 index: 45%. (a) Post-contrast image of the tumor demonstrating ring enhancement with a linear enhancing component; (b) overlay of the same image with IAUGC perfusion map, red denotes high perfusion.

Figure 2

T2-weighted MRI image that shows the tumor’s location in the axial slice (a). Perfusion mapping (red shows elevated perfusion) and progressive contrast change show washout in the tumor’s periphery (b).

Figure 3

Case presented with diffuse heterogeneous-enhancing Luminal B tumor in the left breast with high Ki-67 proliferation index (67%). (a) Last phase post-contrast image of the tumor. (b) IAUGC map of the tumor at the same level (red color denotes elevated perfusion). (c) IAUGC map showing spherical axillary lymph nodes with increased perfusion.

Figure 4

Distribution of cases.

Figure 5

Scatterplots of K^trans (left) and IAUGC (right) with Ki-67 index.