Purpose: To determine the response rate of postmenopausal breast cancer patients to the gonadotropin-releasing hormone (GN-RH) agonist, Zoladex (goserelin; ICI Pharma, Wilmington, DE).
Patients and methods: A multi-institutional single-agent trial in postmenopausal patients was conducted. Serum levels of follicle-stimulating hormone (FSH), testosterone, and estradiol were requested before and after Zoladex treatment.
Results: For estrogen receptor-positive (ER+) patients, the response rate was 11%, with one complete response (CR) and three partial responses (PRs) among 36 eligible patients. Responses were of short duration. There were no responses among 16 estrogen receptor-negative (ER-) patients.
Conclusion: GN-RH agonists have activity in ER+ postmenopausal patients, but response rates are not as high as with other available endocrine therapies and the duration of response is short.