A Phase II Trial of Anastrozole in Advanced Recurrent or Persistent Endometrial Carcinoma: A Gynecologic Oncology Group Study

Abstract Background. Some endometrial cancers are hormonally dependent. A principal source of circulating estrogen is conversion of adrenal androstenedione by aromatase. Anastrozole (Arimidex) is an oral nonsteroidal aromatase inhibitor which is active in recurrent breast cancer. This Phase II study was undertaken to evaluate anastrozole in recurrent endometrial carcinoma. Methods. Patients with advanced or recurrent endometrial cancer not curable with either surgery or radiation therapy and with measurable disease, a GOG (Zubrod) performance status of ≤2, no more than one prior hormonal therapy regimen, and no prior chemotherapy were eligible. Anastrozole was administered at a dose of 1 mg/day orally for at least 28 days. Results. Twenty-three patients were entered on this trial. On central pathology review, 9 of them had grade 2 and 14 had grade 3 tumors. One to 24 courses (median: 1) of therapy were administered. Two partial responses were noted (9%; 90% confidence interval 3 to 23%). Two additional patients had short-term stable disease. With the exception of 1 case of venous thrombosis, the toxicity profile was mild. Median durations of progression-free survival and overall survival are 1 and 6 months, respectively. Conclusions. Anastrozole has minimal activity in an unselected population of patients with recurrent endometrial cancer.