Pattern of metastatic spread and prognosis of breast cancer biologic subtypes.

e12532 Background: Few studies have described patterns of metastatic spread according to the major breast cancer biologic subtypes (BS). The aim of this study was to determine the association of BS on metastatic spreading and to define the associated prognosis in terms of overall survival (OS), progression-free survival (PFS) and survival post-progression (SPP). Methods: We analyzed a series of 544 consecutive patients receiving anticancer treatments for metastatic breast cancer (MBC) at the Department of Oncology of Udine, Italy, from 2004 to 2013. BS were defined according to St Gallen 2013 criteria. Unconditional logistic regression and Cox regression were performed by uni- and multivariate models. Results: Results were described by reporting Luminal A as the reference variable. Non luminal HER2 subtype was associated with a higher rate of liver metastases (OR=3.61 95%C.I. 1.36-9.58, P=0.01), whereas triple negative breast cancer showed a higher tropism for lung (OR=4.30 95%C.I. 1.41-13.1, P=0.01). All...