Impact of Standardized Intraoperative Ultrasound on Re-excision Rates in Breast-Conserving Surgery

The primary objective of breast-conserving surgery (BCS) is complete excision of the tumor with histologically negative margins (R0 resection). Intraoperative ultrasound (IOUS) has been shown to reduce re-excision rates (R1) for sonographically visible breast cancer. However, a standardized IOUS technique has not yet been established. This study aimed to evaluate whether standardization using the "Tübingen Ultrasound Ruler" can reduce R1 resection rates.

This retrospective study included 273 patients who underwent BCS between January 2020 and December 2023 for unilateral or bilateral ductal carcinoma in situ and/or invasive breast cancer, regardless of tumor biology, the presence of microcalcifications, or prior chemotherapy. All surgeries were performed by a single surgeon. Tumors were excised with a sonographically assessed margin of >10 mm in all directions. After specimen imaging, additional margin shavings were obtained when indicated.

A total of 282 specimens were analyzed, with a mean specimen weight of 110.5 g. Considering the main resection specimen alone, the R1 rate was 18.8%. Targeted IOUS-guided shavings significantly reduced the R1 rate to 8.5%. Compared with the mean R1 rate of the average figures of OnkoZert-certified breast centers reported between 2020 and 2023 (12.34%), the use of the "Tübingen Ultrasound Ruler" in combination with specimen imaging was associated with a significantly lower R1 rate (p = 0.043).

Standardization of the IOUS technique combined with imaging-guided targeted shavings makes it possible to achieve a low R1 rate (8.5%) in breast-conserving surgery.