Open surgical biopsy is the "gold standard" or "reference standard" method of evaluating a suspicious breast lesion because it is thought to be very accurate in diagnosing these lesions. While generally considered safe, it is a surgical procedure that, like all surgeries, places the patient at risk of experiencing morbidities and, in rare cases, mortality. However, only 20 to 30 percent of women who undergo breast biopsy procedures are diagnosed with cancer. A less invasive method for evaluation of suspicious breast lesions would be preferable if it were sufficiently accurate. This book examines the effectiveness of core-needle and open-surgical biopsy in breast cancer evaluation.