Experience of hormonal therapy with anastrozole for previously treated metastatic breast cancer

Recent years have brought significant progress to the development of hormonal therapies for the treatment of breast cancer. Several new agents have been approved for the treatment of breast cancer in the metastatic setting, among which is the new non-steroidal aromatase inhibitor, anastrozole, introduced for clinical use in Israel in March 1997.

To evaluate the response rate and survival duration of patients treated with anastrozole for metastatic breast cancer, who had previously received at least one line of hormonal therapy.

Anastrozole was administered to 37 patients with metastatic breast cancer. The median age was 64 years. Estrogen receptor was positive in 20 patients, negative in 10 and unknown in 7. All patients were previously treated with tamoxifen in the adjuvant setting or as first-line hormonal therapy for metastatic disease. Anastrozole was given orally, 1 mg/day. Response was evaluated 2 months after the initiation of treatment and reevaluated every 2 months. Therapy was given until disease progression. Ten ER-negative patients were excluded from the final analysis.

Twenty-seven patients were eligible for response and toxicity analysis. The median follow-up was 20 months. One patient (3.7%) achieved complete response and remains free of disease 28 months after start of therapy. No partial responses were seen. Twenty patients (74%) had stable disease. Two year actuarial survival was 57%. Median survival was 26.5 months after starting therapy and median progression-free survival was 11 months. The toxicity was mild: one patient (3.7%) complained of weight gain and one patient (3.7%) had mild fatigue.

Although the response rate was low, hormonal therapy with anastrozole seems to be beneficial in terms of disease stabilization, freedom from progression, and overall survival without serious toxicity.