Failure of goserelin ovarian ablation in premenopausal women with breast cancer:: Two case reports

Objective. We hereby report on two patients receiving goserelin due to breast cancer in whom a failure in ovarian ablation was detected. A review of the hormonal effects of LHRH analogues is performed. Case reports. Case 1: A 36-year-old female was diagnosed with breast carcinoma and treated with surgery, chemotherapy, radiotherapy, and goserelin. A 16-week gestation was detected after 17 months of uninterrumpted hormonal therapy at ablative doses. Case 2: A 41-year-old female was diagnosed with breast carcinoma and treated with surgery, chemotherapy, radiotherapy, and tamoxifen. Goserelin was substituted for tamoxifen due to bone metastases and, 2 years later, a failure in ovarian ablation was confirmed after the reappearance of the patient's menses. Conclusions. Goserelin-induced ovarian ablation may fail after the use of appropriate doses of this drug. We suggest a possible mechanism of hormone resistance induced by the long-term administration of LHRH analogues. No fetal damage was detected after goserelin exposure in the first 4 months of gestation. (C) 2000 Academic Press.