Extended therapy with letrozole as adjuvant treatment of postmenopausal patients with early-stage breast cancer: a multicentre, open-label, randomised, phase 3 trial
In postmenopausal patients with breast cancer who have already received 2–3 years of tamoxifen, extended letrozole (5 years) was associated with an improved disease-free survival (DFS) compared to 2-3 years letrozole (12-year DFS 67% v 62%; HR 0.78, 95% CI 0.65–0.93; p=0.0064).
Source:
The Lancet Oncology
SPS commentary:
The 12-year overall survival was 88% (95% CI 86–90) in the extended group versus 84% (82–87) in the control group (HR 0.77, 95% CI 0.60–0.98; p=0.036) with treatment divergence at 9.5 years. No overall survival advantage was noted at earlier follow-up, which shows the need for longer follow-up. There was an increased risk of osteoporosis in the extended group (8.3% v 4.7% control) but no difference in fractures or cardiovascular disease.
A related Comment notes that this study addresses the important question of optimal duration of adjuvant aromatase inhibitor therapy. It is similar to the DATA trial, which evaluated extended anastrazole (6 v 3 years) following 2–3 years of tamoxifen; this did not meet the primary endpoint of 5-year disease-free survival (83.1% vs 79.4%; HR 0.79; p=0.066), although a 9-year disease-free survival analysis is planned for 2021. The authors say that the currently available data seem to recommend 5 years of aromatase inhibitor for postmenopausal women who have already completed 2–3 years of tamoxifen. However early therapy discontinuation remains an important issue and better ways to promote adherence are needed.