Local Treatment Issues in Women with Hereditary Breast Cancer

Through carefully designed randomized trials for early stage breast cancer, breast-conserving surgery followed by whole breast radiation therapy (RT) has been shown to result in survival equivalent to that achieved with modified radical mastectomy while affording a woman the opportunity to preserve her breast (1-6). However, in women with hereditary breast cancer, outcomes following mastectomy versus breast-conserving therapy have not been directly compared. Thus, comparability of rates of local control, disease-specific survival, overall survival, and toxicity by treatment is unproven. In addition, questions have been raised as to whether the baseline elevated breast cancer risk in women with hereditary disease will be further increased due the use of radiotherapy to the breast for treatment of the index cancer. Given the limited number of patients diagnosed with hereditary breast cancer each year and the uncertainty whether these women would consent to a randomization between mastectomy and breast conservation, it is doubtful whether a randomized comparison will ever occur. Thus, our current knowledge of ipsilateral breast tumor recurrence (IBTR) following the use of breast-conserving surgery and RT and the risk of developing a contralateral breast cancer in women with hereditary breast cancer is based upon single and multi-institutional retrospective analyses and prospective nonrandomized studies, primarily in women who are known carriers of a BRCA1/2 breast cancer susceptibility gene. The potential implications of a conservative approach and actual clinical results, with emphasis upon women with a known deleterious BRCA1/2 mutation, will be presented in this chapter.