Advances in Radiation Treatment of Patients With Breast Cancer

B reast cancer is the most commonly diagnosed cancer in women in the United States; in 2003, an estimated 211,300 new cases will be diagnosed (Jemal et al., 2003). Early-stage breast cancer (i.e., stage I or II) is treated with lumpectomy followed by breast irradiation (i.e., breast-conserving therapy) or mastectomy. Large randomized clinical trials have shown that mastectomy is an equivalent treatment option to lumpectomy and radiation therapy (Arriagada, Le, Rochard, & Contesso, 1996; Fisher et al., 2002; Jacobson et al., 1995; van Dongen et al., 2000; Veronesi et al., 2002). Patients also undergo a sentinel lymph node biopsy (SLNB) and/or an axillary lymph node dissection (ALND) to determine the extent of the disease. Adjuvant systemic treatment may be indicated if patients have unfavorable pathologic features (e.g., a tumor larger than 1 cm, lymphovascular invasion, lymph node involvement, high nuclear grade and/or histologic grade, Her2-neu overexpression, hormone receptor negative status). Systemic therapy may include chemotherapy and/or hormonal therapy. Patients who are estrogen and/or progesterone receptor positive may be considered for adjuvant hormonal therapy initiated during or after the completion of radiation therapy (National Comprehensive Cancer Network, 2002). Radiation Therapy