Risk Value for Positive Surgical Margins Estimated by Web-based Nomogram in Breast Cancer Patients with Breast-conserving Surgery

Abstract

We examined the usefulness of a nomogram for predicting the surgical margin status during breast-conserving surgery. The subjects were 138 patients with T1/2 breast cancer treated between January 2010 and December 2013. We retrospectively analyzed risk values for positive surgical margins using the web-based nomogram prepared by Groningen University, and compared the values between a positive and a negative margin group. In addition, an optimal cut-off value was calculated using ROC analysis because intraoperative pathological examination for marginal status may be omitted in patients with a lower risk value than the cut-off value. The median age was 59.5 years, and the median tumor diameter was 14.5 mm. The rate of a positive margin on the intraoperative examination was 15.2%. The median risk values in the positive and negative margin groups were 23.0 and 7.0%, respectively, demonstrating a significant difference. The optimal cut-off value was 14.0%, and 96 (69.6%) of the 138 patients had a risk value of <14%. Of these, only 3 were diagnosed as positive with the permanent pathological examination. Based on these data, a prospective clinical study is needed to validate the usefulness of the nomogram.