Differences in the receptor status between primary and recurrent breast cancer--the frequency of and the reasons for discordance.

Objective: Receptor discordances between primary and recurrent breast cancer have been described for years, but only a few analyses have elucidated the factors that influence receptor changes.

Methods: Explorative analyses of prospective data from a breast cancer database of a tertiary breast cancer unit.

Results: Recurrent tumours that had expressed oestrogen (ER) and progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER2) as primary tumours were negative for the respective receptor in 22.