Role of trastuzumab in infracentimetric HER2-positive breast cancer: The southern Italy experience.

e11512 Background: HER2 positive (HER2+) disease is relatively uncommon in early infracentimetric breast cancer (BC) accounting for approximately 10% of cases. Trastuzumab (T) based-adjuvant therapies have shown benefit in patients (pts) with HER2+ tumors with diameter ≥1 cm or positive lymph nodes, based on evidence from large clinical trials. Nowadays, scant data concerning the role of trastuzumab in infracentimetric HER2+ disease have been reported. The aim of this study is to identify the pattern of use of T and risk of recurrence in this setting. Methods: This observational, multicenter, retrospective study was conducted in 13 oncology centers in Sicily from 2005 to 2011. Multifocal and metastatic tumors were excluded. Results: Among our case series, 96 pts were included. Median age was 54 years (range 36-77). Tumor stage: T1a 29 (30.2%) and T1b 67 (69.8%). Nodal status: N0 73 (76%). Histological type: Ductal 91 (95%), Lobular 4 (4%) and Medullary 1 (1%). Histological grade: G1 3 (3.1%); G2 55 (57.3%...