Is Radiotherapy an Option for Early Breast Cancers With Complete Clinical Response After Neoadjuvant Chemotherapy?

Purpose: To determine whether the exclusive use of radiotherapy (ERT) could be a treatment option after complete clinical response (cCR) to neoadjuvant chemotherapy (NCT) for early breast cancer (EBC). Methods and Materials: Between 1985 and 1999, 1,477 patients received NCT for EBC considered too large for primary conservative surgery. Of 165 patients with cCR, 65 patients were treated with breast surgery (with radiotherapy) and 100 patients were treated with ERT. Results: The two groups were comparable in terms of baseline characteristics, except for larger initial tumor sizes in the ERT group. There were no significant differences in overall, disease-free and metastasis-free survival rates. Five-year and 10-year overall survival rates were 91% and 77% in the no-surgery group and 82% and 79% in the surgery group, respectively (p = 0.9). However, a nonsignificant trend toward higher locoregional recurrence rates (LRR) was observed in the no-surgery group (31% vs. 17% at 10 years; p = 0.06). In patients with complete responses on mammography and/or ultrasound, LRR were not significantly different (p = 0.45, 10-year LRR: 21% in surgery vs. 26% in ERT). No significant differences were observed in terms of the rate of cutaneous, cardiac, or pulmonary toxicities. Conclusions: Surgery is a key component of locoregional treatment for breast cancers that achieved cCR to NCT.