Longitudinal cosmetic outcome after planned IORT boost with low kV X-rays-monocentric results from the TARGIT BQR registry.

"Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/tcr-23-88/coif). ES received personal honoraria and travel costs for scientific talks at meetings and educational events from Carl Zeiss Meditec AG. ES was also an unpaid board member of ISIORT (International Society for Intraoperative Radiotherapy). The other authors have no conflicts of interest to declare."

"Funding: None."

"The TARGIT BQR trial is a multicenter prospective study that included more than 1,000 patients from 10 centers in Germany between September 2011 and December 2020. All patients had a preoperative indication for a tumor bed boost in addition to whole breast irradiation after breast conserving surgery. TARGIT is the acronym for “targeted intraoperative radiotherapy”. It includes an immediate IORT to the tumor bed after tumor resection with a dose of 12 or 20 Gy in a single fraction. This is followed by whole breast irradiation according to the standard protocol of the centers with 40–50 Gy EBRT without further boost. The registration study serves the quality control of the IORT as a boost in breast cancer patients and is registered in clinicaltrials.gov under NCT01440010. The standardized intraoperative procedure of IORT with low-kV X-rays was already described in former publications (,,). Photo documentation regarding cosmetic outcome was available from the University Medical Center Mannheim cohort. Patients had follow-up appointments at baseline, 6 weeks, 6 months, at 12 months and yearly thereafter. Photos were taken in three positions: arms up, arms down and from the side."