Goserelin, a depot gonadotrophin-releasing hormone agonist in the treatment of premenopausal patients with metastatic breast cancer. German Zoladex Trial Group

Abstract

One hundred thirty-four pre- and perimenopausal patients presenting with metastatic breast cancer (median age, 42 years; range, 25 to 55) were treated with goserelin (Zoladex [ICI 118 630]; ICI Pharma, Plankstadt, Germany) a long-acting gonadotrophin-releasing hormone (GnRH)-analogue depot formulation, injected subcutaneously every 4 weeks, as a first-line therapy. One hundred eighteen patients were evaluable for response. Serum concentrations of estradiol, luteinizing hormones (LH), and follicle-stimulating hormones were significantly suppressed by Zoladex. Mean serum estradiol values fell into the range of castrated or postmenopausal women within 2 to 3 weeks of therapy. This suppression was maintained for the duration of therapy. Overall objective response was: 12 (10.2%) complete remission; 41 (34.7%) partial remission; 33 (28.0%) no change; and 32 (27.1%) progression. In responders, the median time to response was 4 months (range, 2 to 11 months), median duration of response was 8 + months (range 2 to 24 months), and median time to progression was 11 + months (range, 5 to 30 months). Objective responses were seen for different sites of metastases: loco-regional (62.5%), bone (46.7%), visceral (45.0%), and multiple (35.1%). Tumor remission was more common in patients in which the primary tumor was estrogen receptor (ER)-positive (49.3%) or ER-unknown (44.0%), but appreciable response rates were also observed in ER-poor patients (33.3%). Zoladex depot was well tolerated both locally and systemically. It produced effective castration and the objective response rates and duration of remission are at least comparable to those seen following oophorectomy; however, the side effects are less. The use of depot Zoladex avoids the psychological trauma and operative morbidity of the irreversible operative castration.