82 Background: Debate continues as to whether BCT after neoadjuvant chemotherapy (chemo) can achieve long-term local control rates similar to those experienced by patients undergoing surgery first, especially in those presenting with large tumors. This study was performed to evaluate long-term results of BCT for patients undergoing surgery first versus chemotherapy. Methods: 2,984 patients underwent BCT with whole breast irradiation from 1987 to 2005. Clinicopathologic and outcomes data were reviewed and comparisons made between surgery first and chemotherapy patients. Results: 2,331 (78%) patients underwent surgery first; 653 (22%) received chemotherapy first. Overall, chemotherapy patients had more adverse clinicopathologic features (Table). 5 and 10-yr local-regional recurrence (LRR)-free survival rates were 97% (95% CI: 96%-98%) and 94% (93%-95%) for surgery first patients. Chemotherapy downstaged patients presenting with clinical stage II/III disease (608/653; 93%) allowing for BCT, and pathologic findings revealed stage II/III disease in only 305/653 (46%) (p<.001). 5 and 10-yr LRR-free survival rates were 93% (91%-95%) and 90% (87%-93%) after chemotherapy. After adjusting for clinical stage at presentation, there were no differences in LRR between surgery first and chemotherapy patients. On multivariate analysis, age<50, clinical stage III, grade 3, ER neg status, associated DCIS on final pathology, and close/positive margins were associated with LRR. Conclusions: LRR after BCT is driven by biologic factors and not the timing of chemotherapy. Chemotherapy downstages a significant number of patients with stage II/III disease allowing appropriately selected patients to achieve high rates of local-regional control with BCT. [Table: see text]
