Detailed quality-of-life data from the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) Mammary Prevention 3 (MAP.3) trial showed that exemestane given for the prevention of breast cancer “has limited negative impact on menopause-specific and health-related [quality of life] in healthy postmenopausal women at risk for breast cancer.” Previously reported results from the placebo-controlled randomized MAP.3 trial showed that the steroidal aromastase inhibitor exemestane reduced invasive breast cancer incidence by 65%.
“Exemestane had small negative effects on women’s self-reported vasomotor symptoms, sexual symptoms, and pain, which occurred mainly in the first 6 months to 2 years after random assignment. However, these changes represented only a small excess number of women being given exemestane with clinically important worsening of [quality of life] at one time or another; specifically, 8% more in the vasomotor domain and 4% more each in the sexual domain and for pain. No other between-group differences were observed,” Elizabeth Maunsell, PhD, of Hôpital du Saint-Sacrement, Research Centre, in Quebec and colleagues stated in the Journal of Clinical Oncology. “Overall, slightly more women in the exemestane arm (32%) than in the placebo arm (28%) discontinued assigned treatment.”
MAP.3 trial randomized 4,560 postmenopausal women to exemestane at 25 mg or placebo orally daily for up to 5 years. The trial’s primary endpoint was invasive breast cancer incidence, with menopause-specific and general quality of life among the secondary endpoints. At baseline, 4,468 women (98%) completed both the Menopause-Specific Quality of Life Questionnaire (MENQOL) and the Medical Outcomes Study 36-item Short Form Health Survey (SF-36).
“By trial design, MAP.3 intervention ended once the required number of invasive breast cancers had occurred and the main trial objective had been analyzed,” the investigators explained. Consequently, the percentages of participants that had accumulated sufficient follow-up time at trial closure to complete quality-of-life questionnaires were only 39.9% at 3 years, 21.7% at 4 years, and 5.2% at 5 years after random assignment. Quality-of-life questionnaire compliance “was excellent; between 88% and 98% of participants still taking study medication continued to complete these forms at 6 months and years 1, 2, 3, 4, and 5,” the researchers noted.
The negative influence on vasomotor symptoms, which included hot flashes, night sweats, and sweating, were more common in women younger than 60 years old. “The overall prevalence of bothersome sexual symptoms was higher in women younger than age 60, and negative differences attributable to exemestane were seen only in this age group. For the physical domain, the main negative effects of exemestane were for ‘aching muscles and joints’ and ‘difficulty sleeping,’ and this did not differ by age group,” according to the study report.
“No clear effects of exemestane on bothersome symptoms in the psychosocial domain were observed in either age group. Although being severely bothered by ‘poor memory’ was the second most frequently reported symptom in this domain, there were no between-group differences attributable to exemestane at either time or by age group,” the investigators noted. ■
Maunsell E, et al: J Clin Oncol April 7, 2014 (early release online).