Abstract P2-12-04: Surgeon performed intraoperative ultrasound accurately predicts margin status after neaoadjuvant chemotheraphy

Abstract

Abstract Objective: Neoadjuvant chemotraphy (NACT) is the preferred option of treatment in locally advanced and select cases of early stage breast cancer, currently. One of the major aims is to downstage tumor status allowing more conservative surgery with the most acceptable cosmetic outcome. The presence or absence of residual invasive cancer after NACT, is one of the strong prognostic factors for risk of recurrence and the margin status is the other. Due to the excess degree of fibrosis after tumor shrinkage, to accurately predict margin status intraoperatively after NACT is a challenge for surgeon. The aim of the presented study is to evaluate the efficacy of continuous intraoperative ultrasound guided breast conserving surgery (IUG-BCS) in terms of margin status and re-excision rate. The relationship between intraoperative assessment of gross macroscopic and ultrasonographic margins and cavity shavings results, were also analyzed. Methods: Between 2014 and 2017, IUG-BCS were performed to 194 patients after NACT. Surgeon performed continuous peroperative real-time sonographic margin assessment during resection, macroscopic evaluation, specimen US including sonographic analysis of six faces of each specimen, and shaved cavity margins for permanent pathologic assessment were the standard steps of our methodology. Results: Of the 194 patients, 82 (42.5%) had pathologic complete response (pCR) after NAC. The sensitivity of intraoperative ultrasound localization was 100% (194/194 cases). Patients were on average 53 years old (range, 28-65). There was no difference with respect to patient characteristics including age, menopausal status, personal-family history, oral contraceptive usage, body mass index and tumor localization. Mean tumor size was 5.42 cm before NAC and 2.56 cm after NAC, for those excluding ypT0. Of the 112 patients without pCR, tumor free margins were obtained by means of IUG-BCS in 99% (665/672) of margins evaluated sonographically. Moreover, the involved margins were correctly identified by the surgeon via specimen sonography in %71.4 of the cases (5/7) which was confirmed by cavity shaving results. No frozen section analysis was performed and macroscopic evaluation of the specimen predicted nothing significant. According to permanent section analysis of the resected specimens and cavity shavings, no further intervention was required due to margin positivity. IUG-BCS with real-time specimen sonography were unable to predict involved margins in only two cases, both of them proved to be invasive lobular carcinoma without evidence of residual cancer on pathological examination of cavity shavings. Accordingly, negative margins were achieved in 100% of cases at the initial procedure verified by permanent analysis. Conclusion: Continuous intraoperative ultrasound with specimen sonography is an invaluable and effective modality to achieve negative surgical margins after NACT. Furthermore, meticulous sonographic assessment of specimen margins together with cavity shavings from tumor bed could be a feasible method to decrease re-excision rates without frozen section analysis leading to cost-effectiveness. However, the accuracy of sonography should be questioned in case of lobular histology. Citation Format: Karadeniz Cakmak G, Mutlu S, Sen H, Engin H, Bahadir B, Bakkal H. Surgeon performed intraoperative ultrasound accurately predicts margin status after neaoadjuvant chemotheraphy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-12-04.