A new study has reported results of the Tamoxifen Exemestane Adjuvant Multinational (TEAM) phase 3 trial, which compared the long-term effects of exemestane (Aromasin) alone with sequential treatment with tamoxifen followed by exemestane. Aromatase inhibitors such as Aromasin, anastrozole (Arimidex), and letrozole (Femara) have been reported to improve disease-free survival in postmenopausal women with hormone receptor positive breast cancer compared with tamoxifen when given as an initial adjuvant treatment or after two to three years of tamoxifen. The authors therefore compared the long-term effects of these treatments. The study included 9,779 women from nine countries.
Study participants were postmenopausal women (median age 64 years) with hormone receptor positive breast cancer. Participants were assigned randomly to two groups: (1) Aromasin (25 mg once a day, orally) alone for five years (4,904 women); or (2) tamoxifen (20 mg once a day, orally) followed by Aromasin for a total of five years (4,875 women). The primary endpoint was disease-free survival at the five-year mark.
A total of 4,186 (86%) participants in the Aromasin alone group and 4,154 (85%) in the Aromasin-tamoxifen sequential group were disease free at five years. Aromasin alone was found to be associated with a higher incidence of musculoskeletal adverse events (2,448 (50%) vs. 2,133 (44%)), hypertension (303 (6%) vs. 219 (5%)), and hyperlipidemia (e.g., high cholesterol) (230 (5%) vs. 136 (3%)) than was sequential treatment (tamoxifen followed by Aromasin). On the other hand, sequential treatment was found to be associated with a higher incidence of gynecological symptoms (942 (20%) of 4,814 vs. 523 (11%) of 4,852), venous thrombosis (a blood clot that forms in a vein deep in the body) (99 (2%) vs. 47 (1%)), and endometrial abnormalities (191 (4%) vs. 19 (<1%)) than Aromasin alone. The authors conclude that treatment regimens of Aromasin alone or after tamoxifen both are appropriate options for postmenopausal women with hormone-receptor-positive early breast cancer.