Preoperative radiotherapy in patients with locally advanced breast cancer: Tumor response and patient outcome after 26 years of median follow-up.

Abstract

113 Background: Preoperative radiotherapy (PreopRT) in locally advanced breast cancer patients (LABC) has been rarely reported. The purpose of this study was to determine if pathological response to PreopRT could have prognostic value on locoregional control and survival. Methods: From 1970 to 1984, 203 LABC patients were treated by PreopRT, delivering 45Gy in 25 fractions to the breast, supraclavicular fossa, axilla and ipsilateral internal mammary chain. After a median interval of 38 days (range: 5-121 days), radical mastectomy and axillary dissection was performed independently of radiation response. Chemotherapy or endocrine therapy was prescribed according to physician discretion in 28% and 11% of patients, respectively. Premenopausal patients underwent ovarian ablation. Median follow-up was 26 years. Locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) were estimated using the Kaplan-Meier method, the comparison of survival between groups was performed using the log-rank test, multivariate analysis was performed using the Cox model. Results: Thirty-three patients (16.2%) had a pathologic complete response (pCR) in the breast. The 10- and 20-year Kaplan-Meier LC were 90% (95% confidence interval CI: 85-94%) and 84% (95% CI: 77-89%), respectively. The 10 and 20-years DFS were 49% (CI: 42-55%) and 35% (CI: 29-42%), and the 10 and 20-years OS, 56% (CI: 49-63%) and 41% (CI: 35-48%), in that order. Patients with pCR tended to have better DFS (p=0.06) and OS (p=0.07) when compared to patients with partial response or stable/progressive disease. Having a pCR did not significantly influenced LRC (p=0.44). Multivariate analysis showed that a lower number of positive nodes on axillary dissection and younger age were associated with better DFS (p<0.0001 and p=0.02) and OS (p<0.0001 and p=0.007). Conclusions: LCR achieved by PreopRT followed by radical mastectomy in LABC was excellent in this study, despite few patients having adjuvant systemic therapy. Complete pathologic response defined a subgroup of women with a trend toward better DFS and OS. Older patients and those with a higher number of involved axillary nodes had a worse prognosis.