another article with statistics on small (T1a or b)No her2+ breast cancer

[Lani]

J Clin Oncol. 2009 Nov 2. [Epub ahead of print]
Clinical Relevance of HER2 Overexpression/Amplification in Patients With Small Tumor Size and Node-Negative Breast Cancer.
Curigliano G, Viale G, Bagnardi V, Fumagalli L, Locatelli M, Rotmensz N, Ghisini R, Colleoni M, Munzone E, Veronesi P, Zurrida S, Nolè F, Goldhirsch A.

Department of Medicine, Division of Medical Oncology; Division of Pathology, University of Milano, School of Medicine; Division of Epidemiology and Biostatistics; and Department of Statistics, University of Milan Bicocca, Division of Senology, Istituto Europeo di Oncologia, Milano, Italia.
PURPOSE: To assess the prognostic role of HER2 overexpression/amplification in patients with node-negative, pT1a-b breast cancers. PATIENTS AND METHODS: All patients with HER2-positive breast cancer were identified among a population of 2,130 patients whose diseases were staged as pT1a-b, pN0 and who underwent surgery at the European Institute of Oncology from 1999 to 2006. A matched cohort was selected by using variables of hormone receptor status, age, and year of surgery. We estimated rates of local and distant recurrence, disease-free survival (DFS), and overall survival (OS) in the two groups. RESULTS: We identified 150 consecutive patients with pT1a-b, pN0, HER2-positive tumors. No patient received adjuvant trastuzumab. The median follow-up was 4.6 years (range, 1.0 to 9.0 years). In the hormone receptor-positive group, 5-year DFS rates were 99% (95% CI, 96% to 100%) for HER2-negative disease and 92% (95% CI, 86% to 99%) for HER2-positive disease. In the hormone receptor-negative group, 5-year DFS rates were 92% (95% CI, 84% to 100%) for HER2-negative disease and 91% (95% CI, 84% to 99%) for HER2-positive disease. Overall, the hazard ratio (HR) associated with HER2 overexpression was 2.4 (95% CI, 0.9 to 6.5; P = .09). After analysis was adjusted for pT1 stage, hormone receptor-positive disease with HER2-positive status was associated with a worse prognosis (HR, 5.1; 95% CI, 1.0 to 25.7). OS in HER2-positive, pT1a-b, pN0 breast cancer was similar irrespective of the hormone receptor status (P = .93). CONCLUSION: Patients with node-negative, HER2 positive, pT1a-b breast cancer have a low risk of recurrence at 5 years of follow-up. In patients with hormone receptor-positive disease and pT1a-b, N0 tumors, HER2 overexpression was associated with a worse DFS.

PMID: 19884553