Keywords:
Breast, Lymph nodes, Oncology, MR, MR-Diffusion/Perfusion, Chemotherapy, Contrast agent-oral, Surgery
Authors:
G. L. Desi, V. M. Doronzio, A. Timpani, G. Giannetto, C. Maglia, V. Vani, F. Cortese, D. Regge, L. Martincich; Turin/IT
DOI:
10.26044/ecr2019/C-2427
Aims and objectives
Neoadjuvant chemotherapy (NCT) is a management option for locally advanced breast cancer.
The aim of NCT is to reduce tumor volume for the purpose of breast conservation and as a prognostic factor.
The accurate assessment of residual tumor after neoadjuvant chemotherapy is an important prognostic factor for evaluating outcome and survival of the patient.
Inaccuracy in evaluating tumor response will lead to a prolonged chemotherapy course and an unnecessarily wide resection.
Dynamic Contrast-Enhanced MRI (DCE-MRI) represents the most accurate modality in the evaluation of tumor response to NCT.
The sensitivity of this modality is higher than that of conventional imaging (mammography and ultrasound),
in both the identification of pathological complete response and the assessment of residual disease extent at the end of the treatment.
It was recently shown that MRI visualizes tumor response differently depending on the immunohistochemical subtype of the cancer,
well correlating with pathology outcome for triple-negative and Her2 type tumors while it results suboptimal in luminal cancers.
Moreover,
DCE-MRI contemplating intravenous injection of contrast agent,
is not without risks: even though in rare situations,
allergies and nephrogenic systemic fibrosis may occur,
and recent studies proved gadolinium deposition in basal ganglia; although clinical meaning is not sure,
caution is recommended when gadolinium contrast agents are administered,
especially in young patients.
Diffusion Weighted Imaging (DWI) has been investigated as a means of overcoming the limitations of DCE-MRI assessment which is reliant on inherent unique tissue contrast mechanism.
DW imaging makes use of the variability of brownian motion of water molecules in tissue.
It also provides a quantitative imaging biomarker (apparent diffusion coefficient – ADC),
which is demonstrated may help to distinguish between benign and malign findings and to implement DCE-MRI specificity.
Despite it has been studied for over 10 years,
it’s not included in clinical practice yet,
because ADC value is strictly related to technical protocols and hard to standardize.
For this reason,
different authors investigated other potentials of DWI,
including the qualitative evaluation of images acquired with large b-values.
They concluded that it is not inferior to DCE-MRI for detection of breast carcinoma.
Nowadays there is only one study that estimated the role of qualitative evaluation of DWI in the definition of response to neoadjuvant chemotherapy,
demonstrating a sensitivity of 97% and a specificity of 89% compared to a sensitivity of 93% and a specificity of 56% of DCE-MRI.
However,
this study evaluated the assessment of response at breast level.
Then,
purpose of this study is to evaluate the role of qualitative DWI in defining breast and axillary NCT response and planning breast surgery.