The Controversy Regarding Margin Width in Breast Cancer: Enough is Enough

Excerpt

In contemporary practice, there is no debate that appropriately selected patients with early stage invasive breast cancer can be managed with breast-conserving therapy (BCT) to include a segmental mastectomy with a negative margin followed by radiation. This is supported by multiple randomized trials demonstrating equivalent survival after BCT or mastectomy published over two decades ago. Since the publication of these trials showing the efficacy of BCT, the definition of a negative margin has been the subject of frequent debate. One of these trials, the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-06 trial, defined a negative margin as “no ink on tumor.” Other trials required complete resection of the tumor but did not specify a required margin width or did not evaluate microscopic margins. Therefore, despite the acceptance of BCT as the preferred approach for management of patients with early stage breast cancer, the optimal margin width required on a segmental resection has been open to interpretation. This has resulted in substantial variability in treatment often leading to recommendations for reexcision for “wider” negative margins.1 After all, everyone knows that more is better, right? In the current issue of Annals of Surgical Oncology, Moran et al.2 provide a consensus guideline on margins developed by the Society of Surgical Oncology (SSO) and the American Society for Radiation Oncology (ASTRO). This guideline, based on results of a systematic review of 33 studies, suggests that “no ink on tumor” be the standard for an adequate margin in patients with invasive cancer undergoing breast conserving surgery. In order for this “less is better” concept to be implemented into practice on Monday morning, it is helpful to review the goals of BCT and to understand how contemporary practice involves many different multidisciplinary considerations. …