Duration of aromatase inhibitor (AI) therapy for postmenopausal women with early stage breast cancer has been debated for some time. In addition, there have been questions about the impact of longer-duration (> 5 years) AI therapy on quality of life (QOL). Researchers from the Massachusetts General Hospital in Boston evaluated the risk of recurrence after 10 years of AI therapy and its effect on QOL in a randomized, open-label, phase III trial.
A total of 1918 postmenopausal women who had received 5 years of aromatase inhibitor therapy as either initial therapy or after prior tamoxifen were enrolled in the study. Women were randomly assigned to receive letrozole or a placebo. Patient-reported QOL was measured and women also completed a menopause-specific questionnaire.
At a median follow-up of 6.3 years, a 34% reduction in breast cancer recurrence was observed among the women taking letrozole when compared with women who had taken the placebo. A 58% reduction in contralateral breast cancer with letrozole also was observed, although there was no difference in overall survival between the women treated with letrozole or a placebo. There was also no worsening of quality of life in either group.
Goss PE, Ingle JN, Pritchard K, et al. A randomized trial (MA. 17R) of extending adjuvant letrozole for 5 years after completing an initial 5 years of aromatase inhibitor therapy alone or preceded by tamoxifen in postmenopausal women with early-stage breast cancer. J Clin Oncol 2016;34(suppl; abstract LBA1).