Abstract P1-14-19: Breast-Conserving Surgery after Neoadjuvant Chemotherapy is Oncologically Safe for Stage III Breast Cancer Patients

Abstract

Abstract Background The use of breast-conserving surgery (BCS) in patients with large breast tumors downstaged by neoadjuvant chemotherapy (NCT) remains controversial in clinical stage III breast cancer patients because of the possibility of residual tumor and resistance to NCT. The aims of this study were 1) to evaluate the local recurrence (LR) rate depending on the use of NCT and 2) to determine the oncologic safety of BCS after NCT by comparing LR between patients treated with preplanned/downstaged BCS and patients treated with NCT and mastectomy in clinical stage III breast cancer patients. Patients and Methods Between 2000 and 2007, 166 patients with clinical stage III breast cancer received BCS or mastectomy after NCT (NCT group) and 193 patients with clinical stage III breast cancer who underwent surgery first (Surgery group). Among 166 patients of the NCT group, 94 patients (56.6%) received mastectomy after NCT (mastectomy after NCT group), 39 patients (23.5%) received preplanned BCS (preplanned BCS group) and 33 patients (19.9%) received downstaged BCS (downstaged BCS group). The LR rates between the groups were compared. Results At a median follow-up period of 66.9 months (range, 6.5 to 104.1 months), 11 patients in the NCT group and 7 patients in the Surgery group had developed LR. The 5-year LR-free survival rates were 93.6% in the NCT group and 95.9% in the Surgery group and the LR rates were not significantly different between the groups (p = 0.196). In the NCT group, LRs were observed in 6 patients in the mastectomy after NCT group, 3 patients in the preplanned BCS group and 2 patients in the downstaged BCS group. The 5-year LR-free survival rates were 94.4% in the mastectomy after NCT group, 92.0% in the preplanned BCS group and 93.9% in the downstaged BCS group, respectively (p = 0.953). Conclusions Our study demonstrated that the LR was not different depending on the use of NCT in the clinical stage III breast cancer patients. Also, clinical stage III breast cancer patients who received preplanned or downstaged BCS after NCT showed similar LR-free survival rates compared to patients who received mastectomy after NCT. This result supports that BCS after NCT in clinical stage III patients is oncologically safe in terms of LR if primary breast tumor size has became 5cm or less after NCT. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-14-19.