Concurrent chemoradiotherapy (CRT) following neoadjuvant chemotherapy (NACT) in locally advanced breast cancer (LABC)

Abstract

11063 Background: Despite broad advances in the treatment of LABC, 30 to 40% of patients responding to NACT develop locoregional relapse. We performed a retrospective analysis of the experience obtained so far in patients with LABC who were treated with CRT after NACT in terms of pathologic complete response (pCR), relapse-free survival (RFS) and overall survival (OS) at our institution. Methods: One hundred and twelve patients with LABC (Stage IIB-IIIB) were treated between January 2000 and December 2003 with NACT with 5FU 500mg/m2, doxorubicin 50 mg/m2 and cyclophosphamide 500mg/m2 (FAC) or doxorubicin 50 mg/m2 and cyclophosphamide 500mg/m2 (AC) administered i.v. in four 21-day cycles. CRT with 60 Gy whole-breast irradiation and concurrent weekly mitomycin 5mg, 5FU 500mg and dexamethasone 16 mg or cisplatin 30 mg, gemcitabine 100 mg and dexamethasone 16 mg. Subsequently they underwent surgery and 6 to 8 weeks later received 2 additional courses of FAC, AC or paclitaxel 90mg weekly for 12 weeks and in estrogen receptor (ER) positive patients hormone therapy. Results: Median tumor size 5 cm; stages IIB, IIIA and IIIB were 21.4%, 42.9% and 35.7% respectively. pCR was 42% (CI 95% 33.2 - 50.5) in breast and 29.5% (CI 95% 21.4 - 37.5) in breast and axillary lymph nodes. Multivariate analysis showed the main determinant of pCR was negative ER (P 0.016). Median RFS has not been reached. The 5 year RFS is 76.9% (CI 95% 68.2 - 84.7). No relationship between pCR and RFS was found. Multivariate analysis showed the main determinant of RFS was the clinical stage (p=0.03). Only one patient had local recurrence. The 5 year OS is 84.2% (CI 95% 75 - 93.2). Toxicity during CRT: grade 1–2 neutropenia 32.2%, grade 1–2 anemia 5.2%, grade 3 radioepithelitis 22.4% Conclusions: This modality has good locoregional control for locally advanced breast cancer with an acceptable toxicity profile. Futher investigation of concurrent chemoradiotherapy should be explored in LABC. No significant financial relationships to disclose.