The early peak of relapse in patients with breast carcinomas that overexpress HER2 oncoprotein and dissemination to the axillary lymph nodes might be related to proliferation of micrometastatic lesions induced by EGF family growth factors released at the time of surgery. If the levels of these growth factors have an impact on relapse, the survival of patients with positive nodes and HER2-positive tumours should be dependent on surgery wideness. To test this hypothesis, HER2 status of primary tumours from patients included in a randomized clinical trial addressing conservative quadrantectomy versus radical mastectomy was retrospectively analyzed. In HER2-negative patients, independently of node infiltration, and in HER2-positive patients without node infiltration, no differences in survival according to the type of surgery were observed. In patients with positive nodes and HER2-positive tumours the estimation of the time-dependent log-hazard ratios showed that radical mastectomy significantly increased early death rates (P=0.037).