Positive surgical margins after breast-conserving surgery for ductal carcinoma in-situ: does histologic grade or estrogen receptor status matter?

PURPOSE: DCIS has been shown to have a higher rate of positive margins following breast-conserving surgery (BCS) than invasive breast cancer. We aim to analyze certain factors of DCIS, specifically histologic grade and estrogen receptor (ER) status, in patients with positive surgical margins following BCS to determine if there is an association. METHODS: A retrospective review of our institutional patient registry was performed to identify women with DCIS and microinvasive DCIS who underwent BCS by a single surgeon from 1999 to 2021. Demographics and clinicopathologic characteristics between patients with and without positive surgical margins were compared using chi-square or Student's t-test. We assessed factors associated with positive margins using univariate and multivariable logistic regression. RESULTS: Of the 615 patients evaluated, there was no significant difference in demographics between the patients with and without positive surgical margins. Increasing tumor size was an independent risk factor for margin positivity (P = < 0.001). On univariate analysis both high histologic grade (P = 0.009) and negative ER status (P = < 0.001) were significantly associated with positive surgical margins. However, when adjusted in multivariable analysis, only negative ER status remained significantly associated with margin positivity (OR = 0.39 [95% CI 0.20-0.77]; P = 0.006). CONCLUSION: The study confirms increased tumor size as a risk factor for positive surgical margins. We also demonstrated that ER negative DCIS was independently associated with a higher rate of positive margins after BCS. Given this information, we can modify our surgical approach to reduce rate of positive margins in patients with large-sized ER negative DCIS.

Clinical utility of breast magnetic resonance imaging in patients presenting with primary breast cancer.

Since magnetic resonance imaging (MRI) of the breast has been shown to be sensitive in identifying the extent of the primary tumor and other foci of cancer, we examined its clinical utility in the surgical management of breast cancer patients. From January 2004 to April 2007, 117 patients with newly diagnosed breast cancer underwent bilateral MRI prior to definitive surgical management. Additional lesions were found in 27 patients (23.1%) in the ipsilateral breast and 19 patients (16.2%) in the contralateral breast. Twelve patients (10.3%) had more than one new lesion identified. Six patients (5.1%) had a larger area of tumor than detected by mammography or ultrasound. Additional biopsies were performed in 27 patients (23.1%). Additional foci of cancer were identified in 17 patients (14.5%): 12 (10.2%) in the ipsilateral breast and 5 (4.3%) in the contralateral breast. This information changed the clinical management in 23 cases (19.7%). Further studies are needed to confirm the benefits of MRI relative to its costs and to further identify the appropriate patients to undergo this imaging procedure.