title: The value of estrogen and progesterone receptor determinations in advanced breast cancer. Estrogen receptor level but not progesterone receptor level correlates with response to tamoxifen.
abstract: Four hundred fifteen patients with metastatic breast cancer with known hormone receptor status received primary treatment with tamoxifen. Measured values for the estrogen receptor (ER, i.e., with estrogen binding) followed a continuous distribution (range, 3 to 1000 fmol/mg of protein). These values correlated positively with age. The response to treatment with tamoxifen correlated with the ER level, with response rates of approximately 80% when the ER level was greater than 30.1 fmol/mg of protein. Two hundred eighteen (218 of 415, 52%) patients had progesterone receptor (PR) values greater than 10 fmol/mg. The PR positivity correlated with the ER level. Patients with PR levels greater than 10 fmol/mg of protein (124 of 226, 55%) had a significantly higher response rate than those with values less than 10 fmol/mg of protein (45 of 189, 24%). However, in a multivariate analysis including both receptor levels, age, site, and number of metastases, only the ER level was significant in predicting the response to treatment with tamoxifen. A quantitative estimation of the ER level thus is the best predictor of response to hormonal treatment with tamoxifen for advanced breast cancer.
authors.affiliation: Department of Medicine Haematology/Oncology, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: W R
authors.initials: WR
authors.lastname: Bezwoda
authors.forename: J D
authors.initials: JD
authors.lastname: Esser
authors.forename: R
authors.initials: R
authors.lastname: Dansey
authors.forename: I
authors.initials: I
authors.lastname: Kessel
authors.forename: M
authors.initials: M
authors.lastname: Lange
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis / Q000473:pathology; D011869:Radioligand Assay; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D012008:Recurrence; D013629:Tamoxifen / Q000627:therapeutic use*
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen