Results for the London investigation into dielectric scanning of lesions study of the MARIA® M6 breast imaging system.

OBJECTIVES: Determine the proportion of breast cancers for which MARIA® findings correspond to the cancer, with stratification by breast density and histological type. Investigate performance in symptomatic lesions. Gain patient feedback on experience with MARIA®. METHODS: MARIA® uses a radio frequency antennae array to measure signal attenuation and back scatter to build up a 3D map of tissue dielectric values. The study was a prospective, single-centre, interventional, post-approval device study. RECRUITMENT: Patients were eligible if they were attending symptomatic breast clinic or had confirmed or suspected breast cancer from any referral source. Recruitment between May 2018 and March 2020. READING: Regions of higher signal compared to background or distinct by shape were considered candidates for lesion correspondence. Up to 4 candidate regions per breast were annotated in likelihood order for representing a true lesion. RESULTS: 389 patients were recruited, and 6 excluded. 114 patients recruited with breast cancers (2 bilateral, 5 multicentric). 57 (47%) malignant lesions showed correspondence between the MARIA® signal and the cancer. Higher correspondence was seen in invasive (50%) than in situ (29%) disease. There was no reduction in correspondence at higher breast density. Reduced signal correspondence in the central scan volume and for small lesions. MARIA® scanning was well tolerated. CONCLUSIONS: We believe that MARIA® signal corresponds to a malignant lesion in 47% of breast cancers examined. ADVANCES IN KNOWLEDGE: Our study, the largest to date for this type of technology, demonstrates successes and limitations of this MARIA® M6 version.

Patient and clinician satisfaction and clinical outcomes of Magseed compared with wire-guided localisation for impalpable breast lesions.

BACKGROUND: Guide-wire localisation remains the most commonly used technique for localisation of impalpable breast lesions in the UK. One alternative is magnetic seed localisation. We aimed to investigate patient and clinician satisfaction in two consecutive cohorts, describe re-excision and positive margin rates, and explore reasons for positive margins and the implications for localisation techniques. METHODS: A single-institution prospective service evaluation of two cohorts of consecutive cases of wire and then Magseed localisation was carried out. Data were collected on patient and clinician satisfaction, clinico-pathological findings, and causes of involved margins. T tests were used to compare continuous variables and Chi-squared test for satisfaction outcomes. RESULTS: 168 consecutive cases used wire-guided localisation (WGL) and 128 subsequent cases used Magseeds. Patients reported less anxiety between localisation and surgery in the Magseed group, and clinicians reported greater ease of use of Magseeds. There were no differences in lesion size, surgical complexity, or re-excision rate between the groups. In a subset of patients receiving standard wide local excision (i.e., excluding mammoplasties), the impact on margin involvement was investigated. There was no significant difference in radiological under-sizing or accuracy of localisation. However, specimen weight and eccentricity of the lesion were statistically significantly lower in the Magseed group. Despite this, re-excision rates were not significantly different (p = 0.4). CONCLUSIONS: This is the first large study of satisfaction with localisation and showed clinician preference for Magseed and a reduction in patient anxiety. It also demonstrated similar positive margin rates despite smaller specimen weights in the Magseed group. Magnetic seed localisation offers an acceptable clinical alternative to guide wire localisation. The impact on local service provision should also be considered.