http://www.cancer.gov/cancertopics/factsheet/Therapy/adjuvant-breast
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National Cancer Institute, National Institutes of Health
Adjuvant therapy is treatment given in addition to the primary therapy to kill any cancer cells that may have spread, even if the spread cannot be detected by radiologic or laboratory tests. Studies have shown that adjuvant therapy for breast cancer may increase the chance of long-term survival by preventing a recurrence.