Quality of Life From Canadian Cancer Trials Group MA.17R: A Randomized Trial of Extending Adjuvant Letrozole to 10 Years

Purpose MA.17R was a Canadian Cancer Trials Group-led phase III randomized controlled trial comparing letrozole to placebo after 5 years of aromatase inhibitor as adjuvant therapy for hormone receptor-positive breast cancer. Quality of life (QOL) was a secondary outcome measure of the study, and here, we report the results of these analyses. Methods QOL was measured using the Short Form-36 (SF-36; two summary scores and eight domains) and menopause-specific QOL (MENQOL; four symptom domains) at baseline and every 12 months up to 60 months. QOL assessment was mandatory for Canadian Cancer Trials Group centers but optional for centers in other groups. Mean change scores from baseline were calculated. Results One thousand nine hundred eighteen women were randomly assigned, and 1,428 women completed the baseline QOL assessment. Compliance with QOL measures was > 85%. Baseline summary scores for the SF-36 physical component summary (47.5 for letrozole and 47.9 for placebo) and mental component summary (55.5 for letrozole and 54.8 for placebo) were close to the population norms of 50. No differences were seen between groups in mean change scores for the SF-36 physical and mental component summaries and the other eight QOL domains except for the role-physical subscale. No difference was found in any of the four domains of the MENQOL Conclusion No clinically significant differences were seen in overall QOL measured by the SF-36 summary measures and MENQOL between the letrozole and placebo groups. The data indicate that continuation of aromatase inhibitor therapy after 5 years of prior treatment in the trial population was not associated with a deterioration of overall QOL.