Breast Cancer Heterogeneity Analysis as Index of Response to Treatment Using MRI Images: A Review

Purpose: Breast tumor structure contains a high degree of heterogeneity. This heterogeneity has been correlated with the level of tumor response to neoadjuvant chemotherapy. A significant number of studies using magnetic resonance imaging have looked into the quantification of intra tumor heterogeneity in breast cancer. Nevertheless, a limited number of these studies have specifi-cally looked at evaluating breast cancer heterogeneity as a biomarker of response to treatment. Methods: In this paper, several heterogeneity quantification methods, which have studied breast cancer response to treatment through MR images, will be presented. Important methodological and technological techniques using experimental design, such as histogram analysis, texture analysis and parametric response mapping (PRM), will be explored. Results: Data acquisition, the number of patients, the number of treatment cycles, and other analysis will be discussed for each presented research case. Furthermore, some proposed methods will be evaluated on our institution MRI dataset, collected between 2013 and 2016. Conclusion: This paper can be used as a guideline for investigators working on breast cancer het-erogeneity as a biomarker of response to treatment.