The Effect of Intraoperative Margin Assessment During Breast Conser ving Surger y for Breast Cancer in a Dutch Cohort

Introduction: Intraoperative specimen radiography is a routinely used procedure to ensure adequate resection of nonpalpable breast tumors. Intraoperative digital specimen mammography (IDSM) is an alternative to conventional specimen radiography (CSR) which provides immediate specimen evaluation and can potentially decrease operation time. IDSM may also result in lower positive margin and re-excision rates. IDSM was implemented in our hospital in 2018. The objective of this study was to evaluate the effect of using IDSM versus CSR on operation time, margin status and re-excision rates in breast conserving surgery. Methods: The present study is a single-center retrospective cohort study with 2 patient cohorts: one which underwent CSR (n = 532) and one which underwent IDSM (n = 475). The primary outcome was the operation time. Secondary outcomes were the margin status of the primary surgery, the cavity shaving rate, and the re-excision rate. Differences bet ween cohor ts were compared using univariate statistics and multiple regression analyses to adjust for variables that were significantly different between the groups. Results: IDSM use was associated with an 8-minute reduction in surgery time (B = -8.034, 95% CI [-11.6, -4.5]; P < .001). Treatment variables independently associated with the operation time included use of IDSM, type of surgery, and performance of cavity shaving. Cavity shaves were more often performed when IDSM was used (24% for IDSM vs. 14% for CSR, P < .001), while the proportion of negative margin rates (93% for IDSM vs. 96% for CSR, P = .070) was comparable. Conclusion: IDSM was associated with a modest reduction in operation time. Surgeons performed more cavity shaves since the introduction of IDSM, but this increase was not reflected by difference in negative margin rates.