Kinetic Heterogeneity of Breast Cancer Determined Using Computer-aided Diagnosis of Preoperative MRI Scans: Relationship to Distant Metastasis-Free Survival.

Background Higher peak enhancement and washout component values measured on preoperative breast MRI scans with computer-aided diagnosis (CAD) are presumed to be associated with worse recurrence-free survival. Purpose To investigate whether CAD-extracted kinetic features of breast cancer and the heterogeneity of these features at preoperative MRI are associated with distant metastasis-free survival in women with invasive breast cancer. Materials and Methods Consecutive women with newly diagnosed invasive breast cancer who underwent preoperative MRI were retrospectively evaluated between 2011 and 2012. A commercially available CAD system was used to extract the peak enhancement and delayed enhancement profiles of each breast cancer case from preoperative MRI data. The kinetic heterogeneity of these features (a measure of heterogeneity in the proportions of tumor pixels with delayed washout, plateau, and persistent components within a tumor) was calculated to evaluate intratumoral heterogeneity. Cox proportional hazards models were used to investigate the associations between CAD-extracted kinetic features and distant metastasis-free survival after adjusting for clinical-pathologic factors. Results A total of 276 consecutive women (mean age, 53 years) were evaluated. In 28 of 276 (10.1%) women, distant metastasis developed at a median follow-up of 79 months. A higher degree of kinetic heterogeneity was observed in women with distant metastases than in those without distant metastases (mean, 0.70 ± 0.2 vs 0.43 ± 0.3; P < .001). Multivariable Cox proportional hazards analysis revealed that a higher degree of kinetic heterogeneity (hazard ratio [HR], 19.2; 95% confidence interval [CI]: 4.2, 87.1; P < .001), higher peak enhancement (HR, 1.001; 95% CI: 1.000, 1.002; P = .045), the presence of lymphovascular invasion (HR, 3.3; 95% CI: 1.5, 7.5; P = .004), and a higher histologic grade (ie, grade 3) (HR, 2.2; 95% CI: 1.0, 4.9; P = .044) were associated with worse distant metastasis-free survival. Conclusion Higher values of kinetic heterogeneity and peak enhancement as determined with computer-aided diagnosis of preoperative MRI were associated with worse distant metastasis-free survival in women with invasive breast cancer. © RSNA, 2020 See also the editorial by El Khouli and Jacobs in this issue.