Axillary lymph node status of operable breast cancers by combined steroid receptor and HER-2 status: triple positive tumours are more likely lymph node positive

AIMS: To examine the frequency of axillary lymph node (ALN) invasion of operable breast cancers by their combined oestrogen receptor (ER), progesterone receptor (PR) and HER-2 status. METHODS: 2227 recently operated cases in one centre were retrieved from the Multidisciplinary Breast Centre database and stratified according to their combined immunohistochemical (IHC) expression of ER/PR/HER-2 status. An equivocal HER-2 status was further analysed by Fluorescence in situ Hybridisation (FISH). The following 6 groups were considered: ER(-)PR(-)HER-2(-) (NNN; triple negative), ER(-)PR(-)HER-2(+) (NNP), ER(+)PR(-)HER-2(-) (PNN), ER(+)PR(-)HER-2(+) (PNP), ER(+)PR(+)HER-2(- )(PPN), ER(+)PR(+)HER-2(+) (PPP; triple positive). For ALN, the following variables were tested in uni- and multivariate models: age at diagnosis (years), tumour size (mm), tumour grade, ER, PR, HER-2 and the combined steroid receptor and HER-2 status. Likelihood ratio chi(2)-tests were used for univariate analysis and logistic regression for multivariate analysis. RESULTS: Triple positive tumours had a higher likelihood of being ALN positive than others (56.2% versus 35.7%; P