Radiotherapy Issues After Neoadjuvant Chemotherapy

Radiotherapy (RT) is standard following neoadjuvant chemotherapy (NCT) and breast-conserving surgery. NCT leads to pathologic down-staging, allowing some patients to undergo breast-conserving therapy (BCT) instead of mastectomy. BCT can also be considered in select stage III patients who respond well to NCT. Clearly-negative surgical margins should be obtained in all patients undergoing BCT. RT is used selectively following NCT and mastectomy. Indications for RT have not been fully established; retrospective data and results from National Surgical Adjuvant Breast and Bowel Project B-18 and B-27 currently form the basis for recommending RT. Patients with locally advanced breast cancer should receive postmastectomy RT (PMRT). Patients with residual nodal involvement require PMRT. Stage I-II patients with a pathologic complete response do not require PMRT. Patients without residual nodal involvement, but with residual breast involvement represent an intermediate-risk group. NCT also provides down-staging in the axilla. The role of axillary RT in the setting of NCT is under investigation in ongoing randomized trials.