Goserelin plus anastrozole as first-line endocrine therapy for premenopausal women with oestrogen receptor (ER) positive advanced breast cancer (ABC)

Abstract

731 Background We have previously reported the use of goserelin plus anastrozole as second-line endocrine therapy for premenopausal women with ER-positive ABC. With randomised data showing superiority of third-generation aromatase inhibitors over tamoxifen as first-line therapy for postmenopausal women with ER-positive ABC, we now report our clinical experience of using anastrozole alongside ovarian suppression (with goserelin) in the same setting in premenopausal women. Methods Twenty premenopausal patients (mean age = 42 (30 - 57) years) (advanced primary = 3, soft tissue = 2, bone = 8, pleura/lung = 3, stomach = 1, liver = 2, bone + liver = 1) with ER-positive ABC seen over a 3-year period were treated with goserelin 3.6 mg 4-weekly plus anastrozole 1 mg daily as first-line therapy. Endocrine therapy was considered therapy of choice except in two patients with liver metastases who did not have chemotherapy due to pulmonary embolism or patient choice. All have disease assessable by UICC criteria and have received the therapy for at least 6 months (except for those who progressed prior). Results Twelve patients (60%) derived clinical benefit (CB) (objective response or durable stable disease for at least 6 months) while eight progressed before 6 months. For the 12 patients who have derived CB, the median duration of response is 20+ months (range: 6 - 36 months). At the time of analysis, therapy is continuing in nine patients. When the two patients with liver metastases for whom chemotherapy was therapy of choice were excluded, the CB rate rose to 66%. Therapy has been well tolerated and no patients came off it because of side effects. Conclusion A combined use of goserelin and anastrozole produces CB with long duration in significant proportion of premenopausal women with ER-positive ABC when used as first-line therapy. Further studies with more patients and longer follow-up are warranted. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration AstraZeneca