Clinical evaluation of Contrast Enhanced Breast CT in women recalled from screening due to calcifications

Breast Computed Tomography (BCT) is a new three-dimensional (3D) imaging
technology that has yet to be thoroughly tested in a clinical environment. BCT
machines were only recently FDA and CE approved, and the number of installed
devices worldwide is around ten (although rapidly rising). Only a few studies
using contrast enhanced breast CT have been conducted in small groups of
patients internationally, albeit with promising outcomes. Despite this, there
is no considerable clinical evidence for the principal role of BCT in various
indications (screening, diagnosis, prognosis). Specifically, the work-up of
patients recalled from screening due to calcifications and their relevant
association with aggressive (higher grade) DCIS are still open issues that need
to be solved, to improve primary prevention.

Sensitivity of CEBCT for DCIS when focal enhancement around calcifications is
deemed positive, and no enhancement is regarded as a negative test outcome.

Observational multicenter cohort study.
All recruited patients recalled from screening (mammography) follow the
diagnostic work up undergoing a Digital Breast Tomosynthesis (DBT) examination.
On top of that a bilateral CEBCT scan using a dedicated breast CT scanner
(Koning, USA) is integrated in the breast imaging part of the study. The
standard clinical practice of stereotactic biopsy follows, in which the
histopathological analysis stages malignant lesions with respect to their
aggressiveness.

The main risks associated to performing CEBCT examinations are related to the
use of ionizing radiation and that of contrast agent administration. The risks
of this study are reduced as much as possible. Although the additional
radiation to which the woman is exposed during CEBCT (one pre- and one
post-contrast acquisitions are needed) amounts to double that of diagnostic
mammography, the associated risk is considered to be relatively low when
compared to the benefits that it can bring.1-3 During breast CT examinations
only the breast is exposed to ionizing radiation, sparing the rest of the chest
to any significant amount of ionizing radiation.
Additionally, by performing CEBCT the diagnostic yield of biopsies (i.e., the
percentage of biopsies that show cancer), which is currently of only ~20%,4
will be increased. This will be achieved since calcified lesions that enhance
at CEBCT, which are more often associated to DCIS5,6, will be biopsied, while
those that do not enhance, normally representing benign microcalcifications,
will not be biopsied. Moreover, avoiding biopsy has positive effects on women,
who are spared from the stress related to both the invasive procedure and the
anxiety of the results of the biopsy.
Finally, the risks related to contraindications or potential adverse reactions
for iodine-based contrast agents (allergies, nephropathy) need to be assessed
prior to the CEBCT imaging examination for each single patient (see appendix A
(Radboudumc specific) and appendix B (NKI specific)).

The introduction of an imaging technology such as CEBCT will allow for
improvement of the standard current clinical workup of recalled
microcalcifications, which translates into prevention of invasive breast
cancer. By optimizing the image quality of this modality, we will ensure that
this impact on women*s healthcare is maximized. The research will not be
directly beneficial to the subjects since the research breast CT results will
not influence the subject*s care pathway. However, results of this research
study may impact the potential clinical examinations of thousands of women
annually. In particular, for women recalled for calcifications at screening
mammography it will reduce the overdiagnosis and the number of painful biopsies
of relatively harmless abnormalities.