Intraoperative radiotherapy with electronic brachytherapy system in breast cancer patients: Systematic review

Background: The long-term effectiveness and cosmetic outcomes after intraoperative radiotherapy (IORT) delivered with Xoft® Axxent® Electronic Brachytherapy (eBx®) System in early breast cancer (EBC) is still under evaluation. This system is available in 11 countries around Europe. We aimed to investigate the experience of the European countries with this system and compare the outcomes with the first results in Bulgaria. Methods: We search the PubMed, Scopus and ScienceDirect for clinical trials published before 2019, investigating the effectiveness of an IORT delivered with Axxent® eBx® system as a single radiation dose (20 Gy) in patients with EBC. Our search strategy included: “breast cancer, IORT, Axxent”, “breast cancer, IORT, electronic” and “Axxent, breast”. The identified final reports were compared to a prospective case series of 12 patients fulfilling the GEC- ESTRO low risk group criteria and treated at Department of surgery, Alexandrovska University Hospital, Sofia, Bulgaria. Results: We searched through 791 results and found 13 eligible studies (Ivanov (2011); Costa (2015); Dickler (2015); Hanna (2015); Zammit (2016); Chowdhry (2017); Hung-Wen Lai (2017); G. Proulx (2017); Olsen (2018); Osorio (2018); Lozares (2018); Silverstein (2018) and Syed (2018)), with a total of 3319 patients. Only Dickler reports results from 5-years follow up. Five of the studies were conducted in Europe. The first published European results come 4 years after the first results from US. Comparison of the outcomes of European studies with ours is shown on Table.Table130P European studies evaluating the effectiveness of Axxent® eBx® system, single dose, 20GyStudyCountryPatients (N)Median follow up (months)Cosmetic outcomesRecurrence, %CostaPT3018excellent3.3ZammitUK25>12excellent0OsorioES24216goodxLozaresES150xx0SyedUSA / PT117419.5x0.85VasilevaBG1215excellent0 Open table in a new tab Conclusions: The European studies using the Axxent® eBx®system for IORT show excellent cosmetic results, low recurrence rate and convenience for both patients and medical team in terms of duration of treatment. Still, trials with larger number patients and longer follow up time are needed for conclusions on recurrence rates. Legal entity responsible for the study: Mariela Vasileva-Slaveva. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.