Abstract P3-13-04: Radioactive seed localization in non-palpable breast cancer compared to wire-guided localization and radio-guided occult lesion localization: Results of a comparative study

Introduction Almost 25% of women diagnosed with breast cancer have a non-palpable tumor. In breast-conserving therapy, it is important to have oncologic clear margins while excising minimal healthy tissue with good cosmetic outcome. The three most used techniques for non-palpable tumor localization pre-operative are radioactive seed localization (RSL), wire-guided localization (WGL), and radio-guided occult lesion localization (ROLL). Besides the advantage of tumor localization, each technique has its own disadvantages. When RSL is used, the major concern is safe handling of the seeds because of the used radioactive material. In case of WGL, the ideal skin incision and accurate positioning of the wire do not always match. The tip of the wire is non-palpable during surgery, which increases the risk of positive margins and increases the risk of enlarging resection volume resulting in poor cosmetic outcome. Moreover, the wire can get displaced or can be transsected during surgery. Disadvantages of ROLL include diffuse spread of the radioactive tracer in the breast tissue, which can result in higher excision volumes and problems with the concurrent sentinel node procedure. Thus far, no study has been performed comparing these three techniques. Therefore, this study analyzed the outcomes of RSL, WGL, and ROLL in non-palpable breast cancer in a single institution. Methods Women diagnosed with ductal carcinoma in situ or non-palpable invasive breast carcinoma (stadium I or II) and were operated from January 2011 to December 2013 were retrospectively included in this study (N=278). In all included women in this study, RSL (n=71), WGL (n=78) or ROLL (n=132) was performed for intra-operative tumour localization. Outcome measures were weight of the resected specimen, oncological margins, re-excision and recurrence of disease. Results In total 278 lumpectomies were performed in 272 patients. Mean resection volumes were not significant higher in RSL (mean 97.8 cm3), compared to WGL (mean 80.9 cm3) and ROLL (mean 84.8cm3). RSL was associated with significant less tumor-positive margins (n=55, 96.5%) compared to the WGL (n=55, 73.3%) and ROLL (n=111, 84.1%). Also, RSL was associated with significant lower re-excision rates (n=1, 1.4%) as compared to WGL (n=12, 15.4%) and ROLL (n=14, 10.6%). In only one patient with ROLL, recurrence of disease was seen. The median follow-up of all patients was 27 months (9 – 44). Conclusion This study revealed that RSL is an effective technique for excision of non-palpable breast cancer and is associated with fewer tumor-positive margins and therefore lower re-excision rates. Citation Format: Theunissen CIJM, Noorda EM, Rust EAZ, Bandel C, Ooster- van den Berg JGv, Edens MA, Jager PL, Francken AB. Radioactive seed localization in non-palpable breast cancer compared to wire-guided localization and radio-guided occult lesion localization: Results of a comparative study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-13-04.