Influence of neoadjuvant chemotherapy on radiotherapy for breast cancer.

Neoadjuvant chemotherapy is a standard treatment option for patients with locally advanced operable breast cancer and is increasingly used in early breast cancer. Initial randomized trials of neoadjuvant chemotherapy established equivalency to adjuvant chemotherapy in terms of survival, but they also demonstrated improved rates of breast conservation and the ability to modify the risk of locoregional recurrence after a favorable response to chemotherapy. High-quality nonrandomized data have helped to tailor radiotherapy treatment recommendations after neoadjuvant chemotherapy and breast-conserving surgery or mastectomy. Results from an ongoing phase 3 randomized trial (NSABP B-51/RTOG 1304) will help to clarify the value of locoregional radiotherapy for patients with clinical N1 disease that becomes node negative after neoadjuvant chemotherapy.