Changes in multiple or sequential @entity172 receptor determinations in XXXX .

@entity172 @entity1 @entity5 @entity0
@entity172 receptor (ER) analyses are widely used in the management of @entity1 with @entity0 . Few data are available concerning variations in ER as a function of time and therapy. We examined @entity1 in whom multiple biopsies and receptor analyses were either performed simultaneously or over time with or without intervening chemotherapy or endocrine therapy. In 27 @entity1 with simultaneous assays from different metastatic sites, concordant results were obtained in 23 (85%) with respect to classifying a @entity5 as ER+ or ER-. In 34 @entity1 , multiple assays were performed over time. The receptor concentrations were concordant in @entity1 receiving no intervening therapy. In 10 @entity1 receiving hormonal therapy, the median receptor concentration changed from 66 femtomoles per mg cytoplasmic protein pretherapy to 8 femtomoles post therapy (P less than 0.05). This change suggested that hormonal therapy selectively eliminates ER+ cells. In 19 @entity1 receiving intervening chemotherapy, the median receptor concentrations pre and post therapy were similar. We conclude that simultaneous assays from multiple metastatic sites are highly concordant and unlikely to change over time without intervening therapy, but marked changes occur following therapy with a decrease in receptor concentration after endocrine therapy.
