Impact of locoregional treatment on the early-stage breast cancer patients: a retrospective analysis

Abstract

Although adequate locoregional treatment improves local and regional control in early-stage breast cancer, uncertainty still exists about the role of locoregional therapy with respect to survival. To study the impact of surgery and radiotherapy on locoregional control and survival, we combined the data of three European Organisation for Research and Treatment of Cancer (EORTC) Breast Cancer Group trials including early-stage breast cancer patients with long-term follow-up. Risk ratios (RR) were estimated for locoregional recurrence and overall survival using Cox regression models. All analyses were adjusted for tumour size, nodal status, age, adjuvant radiotherapy, adjuvant chemotherapy and trial. The combined data-set consisted of 3648 patients. The median follow-up period was 11 years. 5.9% of the patients who underwent mastectomy and 10.8% of the patients who underwent breast-conserving therapy had a locoregional recurrence (P<0.0001). The risk of death after breast-conserving therapy was similar compared with mastectomy (RR 1.07, P=0.37). Adjuvant radiotherapy after mastectomy was associated with a lower risk for locoregional recurrence (RR 0.43, P<0.001) and death (RR 0.73, P=0.001). Patients with 1-3 positive nodes benefited the most from radiotherapy after mastectomy. Breast-conserving therapy was associated with an impaired locoregional control. However, breast-conserving therapy was not associated with a worse overall survival. Adjuvant radiotherapy in mastectomised patients was associated with both a significantly superior locoregional control and overall survival. The effect of adjuvant radiotherapy was most profound in patients who had 1-3 positive nodes.