Rochester, Minn. — Unique laboratory testing during breast cancer lumpectomies to make sure surgeons removed all the cancerous tissue spares patients the need for a repeat operation in roughly 96 percent of cases at Mayo Clinic in Rochester, a success rate much higher than the rate nationally, a Mayo study shows. Nationally, 13.2 percent of breast cancer lumpectomy patients had to return to the operating room for another lumpectomy within a month of their initial surgery, compared to 3.6 percent at Mayo in Rochester, which uses a technique called frozen section analysis to test excised tissue for cancer while the patient is still on the operating table. The findings are published in the journal Surgery. Dr. Judy Boughey, comments on the study. For more information, go to the Mayo Clinic News Network.