Abstract P1-20-21: The use of intraoperative ultrasound and guidewire placement to obtain low re-excision rates and increased accuracy of excision in impalpable breast lesions at the Cambridge Breast Unit

INTRODUCTION: Increasingly we are dealing with more and more impalpable breast lesions thanks to screening programmes, chemotherapy and in situ disease. There are various techniques already employed for assisting in surgery for impalpable lesions such as radioactive and magnetic markers. All of these have limitations and are only useful in surgery. Ultrasound can be used in clinic and theatre to locate tumours and sonographically visible markers. In our experience in the Cambridge breast unit we have found it is more satisfactory to use guidewires that are intraoperatively or preoperatively placed using ultrasound guidance. This allows for direct approach to the lesion at the same time limiting the dissection and volume of resection. The guidewire allows tactile feedback and helps with precision and accuracy of the excision as reflected in the specimen weights. In this study we look at the outcomes of intraoperatively and preoperatively placed guidewires using ultrasound for impalpable breast lesions between 2015 -2018 in the Cambridge Breast Unit. The primary outcomes are re-excision rate and average specimen weights. METHODS: Patients undergoing breast conservation surgery for impalpable lesions from 01/01/2015 to 30/07/2018 were included. Data was collected retrospectively from our electronic records system EPIC and analysed. RESULTS The results were divided into intraoperative localisations and preoperative localisations. A total of 441 lesions in 415 patients were included in this study. CONCLUSION: Impalpable lesions can be successfully localised using ultrasound guidance and a guidewire both intraoperatively and preoperatively with good outcomes. Intraoperative localisation has lower re-excision rates and specimen weights in our study as well as many other benefits for the patient and surgeon. We have looked into how easily and quickly we can train ultrasound naive trainees in this technique and have achieved good results. Citation Format: Primeera Wignarajah, Vasiliki Papalouka, Parto Forouhi. The use of intraoperative ultrasound and guidewire placement to obtain low re-excision rates and increased accuracy of excision in impalpable breast lesions at the Cambridge Breast Unit [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-20-21.