The Importance of Surgical Margin Control in Breast-Conserving Therapy

Abstract

The basic surgical oncology principle of complete removal of the primary tumor (R0 resection) for nearly all solid tumors has been debated. For the treatment of early-stage breast cancer, on the basis of the systemic view of breast cancer and the clinical data of the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-08 trial and the emphasis on systemic treatment for improving overall survival, it has been suggested that local control during breast-conserving therapy (BCT) was of limited value with regard to overall survival. However, such a strategy, with little attention paid to microscopic tumor-free margins during BCT, may be associated with increased risks of local recurrence and death. A recent meta-analysis of 78 randomized clinical trials from 42,000 patients showed that improved local surgical control at 5 years resulted in a marked improvement in both breast-cancer survival and overall survival at 15 years. These data should not be interpreted to mean that mastectomy should be the standard management strategy. Rather, local recurrence risk factors should be carefully considered for BCT decisions. Olson et al. reported in a recent issue of Annals of Surgical Oncology that intraoperative margin assessment that uses their proposed frozen section analysis substantially contributes to improved local control. Beyond disease-positive or close surgical margins and lack of systemic treatment, young age is a risk factor for local recurrence after BCT. How can we identify the young patients who are at high risk of local recurrence? In the era of molecular and genetic tool–based personalized management of cancer, preoperative genetic testing enables the identification of women with a germ-line BRCA1 or BRCA2 mutation. Primary prevention of breast cancer is urgently needed for patients with BRCA1/2 mutations because they are at extremely high risk of breast and ovarian cancer. Furthermore, emerging evidence supports the hypothesis that among certain BRCA1/2 mutation carriers, a subpopulation of patients with breast cancer is at high risk of ipsilateral or contralateral breast cancer. The risk of contralateral breast cancer was statistically significant in women with the BRCA mutation compared with those without the mutation after BCT. Therefore, for patients with a BRCA1/2-positive test result available before treatment, bilateral mastectomy instead of BCT could be considered. Recent evidence reconfirms the importance of pathologic tumor-free margins in BCT and suggests the need for individually tailoring the best treatment to young patients with breast cancer.