Breast-conserving surgery after tumor downstaging by neoadjuvant chemotherapy is oncologically safe for stage III breast cancer patients.

BACKGROUND: We conducted a retrospective study to evaluate the local recurrence (LR) rate depending on the use of neoadjuvant chemotherapy (NCT) and to determine the oncologic safety of breast-conserving surgery (BCS) after NCT by comparing LR between patients treated with BCS and mastectomy in clinical stage III breast cancer patients.

PATIENTS AND METHODS: Between 2004 and 2007, 166 patients underwent BCS or mastectomy after NCT (NCT group) and 193 patients underwent surgery first (surgery group) in clinical stage III breast cancer patients. Patients whose tumor size became ≤4 cm after NCT, 57 patients underwent mastectomy (mastectomy group) 39 patients underwent preplanned BCS (preplanned BCS group), and 33 patients underwent downstaged BCS (downstaged BCS group). The recurrence rates between the groups and risk factors for LR were analyzed.

RESULTS: The 5-year LR-free survival rates were 93.6 % in the NCT group and 95.9 % in the surgery group (P = 0.108). In the NCT group, the 5-year LR-free survival rates were 96.3 % in the mastectomy group, 94.7 % in the preplanned BCS group and 90.9 % in the downstaged BCS group (P = 0.669). High expression of Ki-67 was a predictor of LR in patients in three groups (Hazard ratio 8.300, P = 0.049).

CONCLUSIONS: Our findings suggest that BCS after NCT in clinical stage III patients is oncologically safe in terms of LR if breast tumor size is ≤4 cm after NCT and Ki-67 is a predictor of LR after NCT.