OBJECTIVES: This study prospectively assessed the effects of exemestane and tamoxifen on the endometrium in patients receiving adjuvant treatment for postmenopausal hormone receptor-positive breast cancer within the Tamoxifen Exemestane Adjuvant Multicenter (TEAM) trial. METHODS: Patients were randomized to receive tamoxifen or exemestane. In a prespecified trial subprotocol, patients underwent transvaginal ultrasound to assess endometrial thickness at baseline and during a 1- to 3-year treatment period. RESULTS: Among 143 evaluable patients, there were no cases of endometrial thickness >10 mm with exemestane, vs. 11 cases with tamoxifen (p < 0.0003). There was a significant difference between the treatment groups regarding time to endometrial thickness >10mm, in favour of exemestane (p < 0.0001). Time to endometrial thickness > 5 mm was significantly longer for exemestane than for tamoxifen (p < 0.0001). Median time to endometrial thickness > 5 mm or censoring was 583 days in the exemestane group versus 315 days in the tamoxifen group. There were also significantly fewer incidences of endometrial thickness > 5 mm at month 6 and month 12 with exemestane compared to tamoxifen (tamoxifen: 6% and 2%; exemestane: 29% and 39%, respectively). After 12 months, mean increases in endometrial thickness from baseline were 2.64 mm and 6.0mm in the exemestane and tamoxifen groups, respectively (p < 0.0006). Moreover, 17 histologically confirmed endometrial changes were observed in the tamoxifen group, vs. one in the exemestane group. CONCLUSIONS:Exemestane was associated with significantly less endometrial thickening than tamoxifen during adjuvant endocrine therapy for postmenopausal hormone receptor-positive breast cancer.
RCT Entities:
OBJECTIVES: This study prospectively assessed the effects of exemestane and tamoxifen on the endometrium in patients receiving adjuvant treatment for postmenopausal hormone receptor-positive breast cancer within the Tamoxifen Exemestane Adjuvant Multicenter (TEAM) trial. METHODS:Patients were randomized to receive tamoxifen or exemestane. In a prespecified trial subprotocol, patients underwent transvaginal ultrasound to assess endometrial thickness at baseline and during a 1- to 3-year treatment period. RESULTS: Among 143 evaluable patients, there were no cases of endometrial thickness >10 mm with exemestane, vs. 11 cases with tamoxifen (p < 0.0003). There was a significant difference between the treatment groups regarding time to endometrial thickness >10mm, in favour of exemestane (p < 0.0001). Time to endometrial thickness > 5 mm was significantly longer for exemestane than for tamoxifen (p < 0.0001). Median time to endometrial thickness > 5 mm or censoring was 583 days in the exemestane group versus 315 days in the tamoxifen group. There were also significantly fewer incidences of endometrial thickness > 5 mm at month 6 and month 12 with exemestane compared to tamoxifen (tamoxifen: 6% and 2%; exemestane: 29% and 39%, respectively). After 12 months, mean increases in endometrial thickness from baseline were 2.64 mm and 6.0mm in the exemestane and tamoxifen groups, respectively (p < 0.0006). Moreover, 17 histologically confirmed endometrial changes were observed in the tamoxifen group, vs. one in the exemestane group. CONCLUSIONS:Exemestane was associated with significantly less endometrial thickening than tamoxifen during adjuvant endocrine therapy for postmenopausal hormone receptor-positive breast cancer.