P2-12-14: Prognostic Value of HER2 Positivity and Negative Hormonal Status in Patients with Small Tumor (<1cm) and Node-Negative Breast Cancer.

Abstract

Abstract Introduction. Human epidermal growth factor receptor 2 (HER2) amplification has become the prototype biomarker to develop tailored biological treatment. Many studies suggested that HER2 positivity is an independent predictor of disease recurrence and breast cancer mortality. Trastuzumab has been introduced into clinical practice for high-risk HER2−positive patients who have completed the standard adjuvant treatment. However, small (<1cm), node-negative tumors remain a subgroup of HER2−positive patients who are currently ineligible for trastuzumab treatment, as clinically they have been deemed to have no requirement for standard adjuvant chemotherapy. The aim of our analysis was to evaluate the prognostic factors of local and distant recurrence in patients diagnosed with T1a-b, node-negative, HER-2 positive breast cancer. Materials and methods. A total of 704 patients were diagnosed at Florence University between November 1999 and December 2008 with node-negative, invasive BC that were 1 cm or smaller. Patients with ductal carcinoma in situ, with recurrent BC at presentation and patients that received adjuvant chemotherapy were excluded from analysis. Results. Mean follow-up was 4.9 years (0.5−10.8 years); we recorded a total of 19 recurrences, including 10 distant recurrences. Mean time to local relapse occurrence was 3.8 years (0.4−7.3 years); mean time to distant metastases diagnosis was 4.4 years (1.4−7.6 years). Among all patients, the recurrence-free survival (RFS) was 93.7%. The only parameter that emerged as significant predictor of events is the age (p=0.02). The distant recurrence-free survival (DRFS) rate was 96.5%. Patients who had HER2−positive BC had worse DRFS than patients who had HER2−negative BC (92.0% v 96.9%; p=0.045). In addition to HER2, also HR status was significantly associated with DRFS (p=0.026). Patients who had HR negative status had worse DRFS than patients who had HR positive status (91.4% v 97.4%; p=0.045). Conclusions. Patients with T1a-b, node-negative, breast cancer have a low risk of distant and local recurrence. Women with HER2−positive and negative hormonal status have a significant risk of distant recurrence and should be considered for anti-HER2 adjuvant therapy. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-14.