Omitting vs. Doing Intraoperative Frozen Section Biopsy for Margin Status in Breast Conserving Surgery

* Study phase: 3 * Indication: Breast cancer patients undergoing breast conserving surgery * Primary objectives: To determine the effect of selective omission of intraoperative margin evaluation via frozen section on margin positive rate Secondary objectives: To determine the effect of selective omission of intraoperative margin evaluation via frozen section on reoperation rate, local recurrence rate, operation time, resection volume, medical cost and patient quality-of life * Hypothesis: Omitting intraoperative margin evaluation via frozen section biopsy in selected breast cancer patients does not increase margin positive rate * Study design: Randomized controlled trial * Sample size: 1292 patients * Procedures: breast conserving surgery +/- margin frozen section biopsy (+/- additional resection)