Is Exclusive Radiotherapy an Option for Early Breast Cancers with Complete Clinical Response after Neoadjuvant Chemotherapy?

Purpose: To determine whether exclusive radiotherapy (ERT) could be an option after complete clinical response (cCR) to neoadjuvant chemotherapy (NCT) for early breast cancers (EBC).Patients and methods: Between 1985 and 1999, 1477 patients received NCT for EBC considered to be too large for primary conservative surgery. Of 165 patients with cCR, 65 were treated by breast surgery (with radiotherapy) and 100 by 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 survivals. Five-year and 10-year overall survivals were 91% and 77% in the no surgery group and 82% and 79% in the surgery group, respectively (p = 0.9). However, a non-significant trend towards 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.Conclusion: Omission of breast surgery in patients who achieved cCR to NCT was not associated with an increased risk of distant metastases or death. However a trend towards an increased risk of locoregional recurrence was observed in the ERT group. Imaging modalities appear to be essential to monitor chemotherapy response and possibly select patients in whom ERT can be proposed. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4108.