Ten-year results from the TEAM trial showed that exemestane alone and sequential treatment with tamoxifen followed by exemestane are both “reasonable adjuvant treatment options” for postmenopausal women with hormone receptor-positive breast cancer.1
At a median follow-up of 9.8 years (IQR, 8.0-10.3), disease-free survival (DFS) was 67% (95% CI, 65-69) for the exemestane group and 67% (95% CI, 65-69) for the sequential group (hazard ratio [HR], 0.96; 0.88-1.05; P
= 0.39). The treatment effect was consistent among all subgroups and investigators did not observe significant interaction between treatment and clinicopathological factors.
During follow-up, 30% of patients in the exemestane group (n = 3075) and 31% of patients in the sequential group (n = 3045) had a DFS event.
“Both the sequential scheme with tamoxifen followed by exemestane and exemestane monotherapy for 5 years are reasonable adjuvant treatment options for postmenopausal patients with hormone receptor–positive breast cancer, with no significant difference in survival after 10 years of median follow-up,” first author Marloes G M Derks, MD, Leiden University Medical Centre, the Netherlands, and coinvestigators wrote.
“This finding allows the possibility for shared decision making between the clinician and patient, balancing individual patient characteristics and preferences, side-effect profiles, and tolerability. Future studies will hopefully show which subgroup, if any, benefits more from a particular strategy, and whether extension of any of these treatments beyond 5 years is worthwhile,” added Derks et al.
Initiated in 2001, the phase III Tamoxifen Exemestane Adjuvant Multinational (TEAM) is a multinational, randomized, open-label trial. Postmenopausal women with histologically-confirmed breast adenocarcinoma and locally assessed estrogen receptor–positive or progesterone receptor–positive disease who had completed local treatment with curative intent were enrolled at 566 hospitals in 9 countries. Patients were assigned to 5 years of exemestane or a sequential scheme of 2.5 years of tamoxifen followed by 2.5 years of exemestane.
Patients assigned to tamoxifen were switched after 2.5 to 3.0 years to exemestane therapy for a total duration of 5.0 years of treatment. Dose reductions were not allowed.
In results published after a median of 5 years of follow-up, investigators found no significant difference in DFS, overall survival (OS), or relapse-free survival between the 2 treatment groups.
In this analysis, published in The Lancet Oncology, all patients from Japan (n = 184), France (n = 1230), and the United States (n = 2232) were excluded due to the absence of long-term data.
Twenty-four percent of patients in both groups died during follow-up, and 10-year OS was nearly identical: 74% (95% CI, 72-75) in the exemestane group versus 73% (95% CI, 72-75) in the sequential group (HR, 0.98; 95% CI, 0.89-1.09; P
Breast cancer recurrence occurred in 18% of patients in the exemestane group and 20% of patients in the sequential group. Cumulative incidence of breast cancer recurrence after 10 years of follow-up was lower in the exemestane group, at 20% versus 22% (subdistribution HR for recurrence-free interval, 0.88; 95% CI, 0.79-0.99; P
In the exemestane group, 15% of patients experienced distant recurrence compared with 16% patients in the sequential group. There was no difference in cumulative incidence of distant recurrence between the 2 arms: 16%, (95% CI, 15-18) in the exemestane group versus 18%, (95% CI, 16-19) in the sequential group. HR for distant recurrence-free interval was 0.91 (95% CI, 0.80-1.03; P
In the exemestane group, 12% percent of patients died of breast cancer compared with 14% in the sequential group. Cumulative incidence of breast cancer–specific mortality after 10 years of follow-up was 13.5% (95% CI, 12.3-14.9) in the exemestane group and 15.4% (13.0-16.9) in the sequential group (subdistribution HR, 0.88; 95% CI, 0.77-1.01; P
Among patients in the exemestane group, 12% died of causes other than breast cancer compared with 10% in the sequential group. Cumulative incidence for other-cause mortality was 12.8% in the exemestane group and 11.3% in the sequential group (subdistribution HR, 1.14; 95% CI, 1.00-1.31; P
= .08). There were no significant differences for cause of death between the treatment groups (P