By: Mike Bassett
5 years of the aromatase inhibitor improved disease-free survival vs 2-3 years
Five years of extended treatment with the aromatase inhibitor letrozole significantly improved disease-free survival (DFS) compared with the standard duration of 2 to 3 years in postmenopausal patients with breast cancer who had already received 2 to 3 years of tamoxifen, according to results from a phase III trial.
After a median follow-up of 11.7 years, DFS events occurred in 20.7% of patients in the extended group and 25.4% of patients in the control group. The 12-year DFS rates were 67% and 62%, respectively (HR 0.78, 95% CI 0.65-0.93, P=0.0064), reported Lucia Del Mastro MD, of the University of Genoa in Italy.
This reduction in the risk of disease recurrence demonstrated in the extended group did not change in a multivariate Cox model (HR 0.79, 95% CI 0.66-0.95, P=0.014), and was consistent across subgroups, she added.
The 12-year overall survival rates were 88% in the extended group and 84% in the control group (HR 0.77, 95% CI 0.60-0.98, P=0.036).
“This regimen can be considered as one of the optimal standard endocrine treatments for postmenopausal patients with hormone receptor-positive breast cancer,” Del Mastro said during a presentation at the virtual annual congress of the European Society for Medical Oncology.
The study was simultaneously published in Lancet Oncology.
Del Mastro and colleagues noted that the optimal duration of extended therapy remains unclear because of differences in duration among competing studies addressing this question. However, she pointed out that the IDEAL and ABCSG-16 trials demonstrated that extended therapy for 10 years was not superior to 7-8 years.
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.