ThP1.3 - Oncoplastic Surgery and Magseed Markers: A five-year snapshot of ambition and evolution in breast conserving surgery

Abstract Aim Oncoplastic surgery and localisation markers allow breast conservation in patients who might previously have been treated with mastectomy. We aimed to evaluate breast conservation across a five-year period spanning widening adoption of oncoplastic conservation, and the introduction of Magseed localisation. Method All patients diagnosed with breast cancer or DCIS, screening or symptomatic, in NHS Lanarkshire during the first 6 months of 2017 and 2022 were reviewed. These dates were chosen to eliminate the effects of Covid-19 on practice as much as possible. Results 531 patients (244 in 2017; 287 in 2022) were diagnosed within the study period. Groups were comparable for age (median 62 (32-96) and 61 years (28-94); P=0.4), and tumour size (median 19 (3-150) and 21 mm (4-123); P=0.4). Breast conservation as first operation rose from 69.1% to 85.5%. Use of localisation also increased, from 52.7% of procedures using wires in 2017, to 71.2% using one or more Magseeds in 2022 (P<0.001). Oncoplastic breast conservation rose from 3% to 7% of procedures. Re-excision rates remained in line with national outcomes (20.4% in 2017 and 20.0% in 2022); and ‘failure’ of breast conservation resulting in completion mastectomy also reduced from 8.0% to 4.7%. Overall mastectomy rate (+/- reconstruction) fell from 36% to 18% (P<0.001). A reduction in mastectomy for multifocal or diffuse disease requiring localisation or bracketing was also observed, from 56.2% to 35.5%, though this didn’t reach statistical significance (P=0.13). Conclusion Increasing success in breast conservation has coincided with greater adoption of oncoplastic breast conservation and novel localisation technology. Reassuringly, this has not resulted in an increase in re-excision, nor completion mastectomy rate.