Clinical outcomes of breast-conserving surgery in patients using a modified method for cavity margin assessment.

BACKGROUND: This study describes a modified intraoperative method for cavity margin (CM) assessment in place of lumpectomy margin assessment in patients undergoing breast-conserving surgery (BCS). METHODS: This is a retrospective review of 422 breast cancer patients undergoing BCS with intraoperative CM assessment. After an initial lumpectomy with intent to obtain ≥1-cm margins, separate specimens 1 × 1 cm, 0.5-cm thick were taken from the cavity margin circumferentially. These were frozen without reference to the side of the new margin as a time-saving measure, and parallel sections of the resected surface were evaluated. RESULTS: After a median follow-up of 55.5 months, a cumulative 5-year locoregional recurrence-free survival rate of 95.3%, metastasis-free survival rate of 97.8%, disease-free survival rate of 88.3%, and overall survival rate of 96.0%, was achieved. The CM positivity rates were of no statistical difference when <7, 7-8, and >8 CMs were assessed. The second operation rate was 3.5% because of the false-negative results of the frozen section analysis on CMs. Univariate and multivariate analysis revealed that a higher pN stage and cT stage as well as a lack of adjuvant chemotherapy or radiation demonstrated significantly worse clinical outcomes. Locoregional recurrences and metastasis are both correlated with worse overall survival. The number of the CMs assessed was not associated with clinical outcomes. CONCLUSIONS: The modified CM assessment presented here is a rapid, accurate, and oncologically safe approach for margin evaluation in BCS patients. Lumpectomy margin assessment might be spared when this method is used.