Assessment and Response to Neoadjuvant Treatments in Breast Cancer: Current Practice, Response Monitoring, Future Approaches and Perspectives.

Neoadjuvant treatments (NAT) for breast cancer (BC) consist in the administration of chemotherapy-more rarely endocrine therapy-before surgery. Firstly, it was introduced 50 years ago to downsize locally advanced (inoperable) BCs. NAT are now widespread and so effective to be used also at the early stage of the disease. NAT are heterogeneous in terms of therapeutic patterns, class of used drugs, dosage, and duration. The poly-chemotherapy regimen and administration schedule are established by a multi-disciplinary team, according to the stage of disease, the tumor subtype and the age, the physical status, and the drug sensitivity of BC patients. Consequently, an accurate monitoring of treatment response can provide significant clinical advantages, such as the treatment de-escalation in case of early recognition of complete response or, on the contrary, the switch to an alternative treatment path in case of early detection of resistance to the ongoing therapy. Future is going toward increasingly personalized therapies and the prediction of individual response to treatment is the key to practice customized care pathways, preserving oncological safety and effectiveness. To gain such goal, the development of an accurate monitoring system, reproducible and reliable alone or as part of more complex diagnostic algorithms, will be promising.

Influence of different post-contrast time points on dynamic contrast-enhanced (DCE) MRI T staging in breast cancer.

PURPOSE: to assess whether MRI T stage of breast cancer lesions (BCLs) is affected by maximum diameter (MD) measured at different post-contrast time points (TPs) on different acquisition planes on dynamic contrast-enhanced (DCE) MRI sequence. METHODS: 53 DCE-MRI examinations of patients with BCLs were retrospectively selected. MD of BCLs was measured on axial, coronal and sagittal planes on DCE images at five different post-contrast TPs. Friedman test followed by Bonferroni-adjusted Wilcoxon-signed rank test for post-hoc analysis was performed to evaluate differences among the five measurements. Reliability of the measurements was evaluated with the intraclass correlation coefficient analysis. Differences between pathological and MRI T stage assessed at each TP on each acquisition plane were assessed using the Wilcoxon-sign rank test; p values <0.05 were considered statistically significant. RESULTS: on axial, coronal and sagittal planes, MD measured at TP1 was significantly different (p < 0.0001) compared to those obtained at the subsequent TPs. No significant differences were found between MD measured at TPs 3, 4 and 5. Intra and inter-observer reliability resulted as very good, with ICC ranging between 0.915-0.992 and 0.845-0.911, respectively. MRI T stage assessed at TP1 on axial and sagittal plane as well as at all TPs on coronal plane was significantly different from pathological T stage. CONCLUSION: MRI T stage definition of BCLs is significantly affected by the TP used for lesions' MD measurement. TPs 3, 4 and 5 are the preferred TPs for the assessment of MRI T stage of BCLs on both axial and sagittal planes.