The safety of breast-conserving surgery in patients who achieve a complete pathologic response after neoadjuvant chemotherapy

BACKGROUND. The objectives of this study were to determine the locoregional recurrence (LRR) rate and to evaluate the correlation between surgical resection volume (RV) and LRR in patients with breast cancer who underwent segmental mastectomy after achieving a pathologic complete response (pCR) on neoadjuvant chemotherapy. METHODS. We reviewed the outcomes of all 109 patients who underwent segmental mastectomy after the complete eradication of invasive disease by neoadjuvant chemotherapy at their institution between 1987 and 2002. LRRs were recorded, and RVs after segmental mastectomy were calculated and categorized as small, medium, or large. RESULTS. At a median follow-up of 6.6 years, 3 patients (2.7%) developed LRR. In 2 of those patients, the recurrence was located in the ipsilateral breast; in the other patient, the recurrence was located in the supraclavicular lymph nodes with synchronous distant metastases. The median RV was 73.12 cm³ (range, 2.82-451.51 cm³). Large RVs (>125 cm³) were less common than small RVs (up to 70 cm³) or medium RVs (between 70 cm³ and 125 cm³; P =.009 and P < .0001, respectively). One patient with a small RV had an LRR at 4 years, and 2 patients with medium RVs had LLRs at 2.3 years and 6 years, respectively. The 5-year and 10-year LRR-free survival rates were 98.1% and 96.5%, respectively, and the corresponding overall survival rates were 96% and 92%, respectively. CONCLUSIONS. Segmental mastectomy was associated with excellent locoregional control in patients who achieved a pCR after neoadjuvant chemotherapy. Prospective studies are needed to examine whether decreasing the RVs in this patient population leads to an increased LRR rate.