Abstract P1-20-20: Intraoperative ultrasound localization (IOUS) for non-palpable breast cancer

Abstract Background: With the introduction of breast cancer screening the number of non-palpable breast cancers and so the number of breast conserving surgery (BCS) has increased. Wire-guided localization (WGL) is used as invasive standard method for localization. IOUS is an alternative non-invasive, time-sparing and safe localization method with many cost benefits. Patient and methods: A retrospective observational study was performed in a single breast unit where IOUS was used as localization method by two surgeons in the period June 2013 to October2016. The surgeons did not have any special experience with Ultrasound (US) apart from one week of bed-side training. Results: During a 41 months period the two surgeons treated 452 with BCS. Of them 126 were non-palpable and visible by US 28%. The 126 cancers were identified with IOUS at surgery and removed successfully by the surgeons. In the period a total of 156 had a BCS with WGL. These cases had a nonpalpable cancer which were non-visible on US with either calcifications, DCIS or non-specific lesions. In the study we also found that the re-lumpectomy rate for BCS with IOUS was lower than without IOUS. In the entire breast unit, the number of BCS were 848 and number of BCS+WGL were 320 in the same period. Of them 263 (22.5%) had a re-lumpectomy. The number BCS with IOUS were 452 and the number of BCS+WGL with IOUS were 156. Of them 72 (11.8%) had a re-lumpectomy. Conclusion: In our breast unit, IOUS was used after a short bed-side training, with 100% success rate, to remove non-palpable cancers if visible on US. IOUS is easy to learn and easy to use and offers many financial and time-sparing benefits. IOUS has a reasonable learning curve and can reduce the work load on the Radiology Department. Citation Format: Shideh Pour Zahed, Thor Knudsen Andersen. Intraoperative ultrasound localization (IOUS) for non-palpable breast cancer [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 P1-20-20.