S31 Treatment of local reappearance of breast cancer

were treated with mastectomy, lymph node irradiation, a lumpectomy cavity radiation boost, or adjuvant chemotherapy. The existing evidence prompted the American Society for Radiation Oncology (ASTRO) to convene a task force to issue an evidence-based guideline in 2010 delineating the patients for whom an abbreviated radiation course is most supported by the current evidence (Table 2). Ongoing and future studies will further clarify the suitability of a hypofractionated treatment approach for the patient subgroups underrepresented in available trials. Additionally, alternative abbreviated treatment regimens, including those in which treatment is given once weekly and treatments that include an integrated lumpectomy cavity boost, are actively being investigated. Finally, innovative radiation techniques, such as the use of higher energies, prone treatment, and breathing-adapted therapy have further increased the homogeneity of breast irradiation and minimized dose delivered to nearby critical normal structures. Consequently, increasing experience with these techniques may expand the population of patients amenable to hypofractionated therapy.