Adjuvant aromatase inhibitor (AI) therapy for 5 years did not improve disase-free survival (DFS) compared with 3 years of AI therapy after 2 years of tamoxifen among patients with hormone receptor (HR)-positive early breast cancer, according to a study published in The Lancet Oncology.1
Previous studies showed that while AIs can improve outcomes in this patient-group, the superiority of treatment schedule and type of AI requires further exploration.
For the phase 3 First Adjuvant Trial on All Aromatase Inhibitors study (FATA-GIM; ClinicalTrials.gov Identifier: NCT00541086), researchers randomly assigned 3697 patients to 1 of 6 treatment groups: upfront AI therapy (anastrozole, exemestane, or letrozole) for 5 years, or tamoxifen for 2 years followed by a switch to 1 of the 3 AIs for 3 years.
After median follow-up of 60 months, 11% (211) of patients in the switch group and 10% (190) of the patients in the upfront group reported having a DFS event. The 5-year DFS rate was 88.5% (95% CI, 87.9%-91.7%) vs 89.8% (95% CI, 88.2%-91.2%) among patients in the switch arm vs upfront arm, respectively (hazard ratio [HR], 0.89; 95% CI, 0.73-1.08; P = .23).
The 5-year DFS rates were 90.0% for patients receiving anastrozole, 88.0% for exemestane, and 89.4% for letrozole (P = .24).
The most frequently reported grade 3 to 4 adverse events included musculoskeletal AEs, occurring in 7% of patients in both study arms.
The authors concluded that upfront administration of AIs for 5 years was not superior to switching to AIs from tamoxifen after 2 years, and noted that “patient preference, tolerability, and financial constraints should be considered when deciding the optimal treatment approach in this setting.”
- De Placido S, Gallo C, De Laurentiis M, et al. Adjuvant anastrozole versus exemestane versus letrozole, upfront or after 2 years of tamoxifen, in endocrine-sensitive breast cancer (FATA-GIM3): a randomised, phase 3 trial. Lancet Oncol. 2018 Feb 23. doi: 10.1016/S1470-2045(18)30116-5 [Epub ahead of print]