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.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Aug 15 1991|
ASJC Scopus subject areas
- Cancer Research