The early diagnosis of breast cancer is of paramount importance, with a 5-year survival rate of 97% if the cancer is caught "locally", deteriorating to 79% if it has progressed to the "axillary" lymph nodes, and 23% if it has spread to the rest of the body, known as "metastasised."
Diagnosis is currently achieved through clinical examination, imaging with mammography (MMG) and/or ultrasound (US) and needle biopsy. Mammography is dependent upon adequate breast compression to allow greater contrast differentiation between tissue structures, this is not only uncomfortable, but in younger women with 'dense' breast tissue the contrast difference between normal tissue and tumour is minimal despite compression. Furthermore mammography uses ionising radiation, which means that a risk/benefit calculation is weighted against repeated or frequent use. Frequently it is necessary to use additional imaging such as ultrasound or MRI for diagnostic support.
Breast tumours have an additional property that can distinguish them from normal and this is defined by the dielectric value. This has two components - the dielectric constant, which affects the velocity of propagation of radio waves and therefore their wavelength, and the conductivity, which affects the rate of attenuation. Typically a tumour has a dielectric constant of 45-50 and a conductivity of 2S/m, whereas breast fat is 5-15 and 0.2-1S/m respectively but with considerable range. Normal glandular tissue is intermediate. These differences in dielectric constant enable a consideration of the value of this data in breast cancer diagnosis.
Several attempts to exploit this property for imaging have been made. The outcomes have been similar in that the presence of a tumour is detectable, however limitations in depth for detection and mode of the technology were identified.
Due to updated technology in the MARIA device, previous limitations from similar studies are not reported to be a problem.
This study aims to determine the proportion of patients with breast cancer who are correctly diagnosed by MARIA, and to stratify this by breast density and histological type. In addition a pilot study will be performed to investigate the imaging characteristics and performance of MARIA in the assessment of benign and malignant lesions in patients attending the symptomatic breast clinic.
The MARIA scan will be in addition to any standard diagnostic procedures, including imaging, that comprise the standard of care. The scan will require them to lie prone for less than 10 minutes with their breast pendant in an ergonomically-fitted bowl with a thin layer of a coupling fluid (similar to hand moisture in consistency) applied to the surface of the breast.
While there is no direct benefit nor detrimental effect from this study to the patients participating, the study has large implications for many women.
This study will allow the investigators to test the feasibility of this highly innovating approach to breast cancer, with minimal negative effects or possible complications. This diagnostic modality could prove to be a major step forwards in cancer detection, initially as a complementary source of information that can increase confidence in results obtained from established technologies that are routinely deployed in the clinic.
