Association between age at diagnosis and disease-specific mortality among postmenopausal women with hormone receptor-positive breast cancer

摘要

The incidence of breast cancer increases with age. The frequency of this cancer is increasing among older women because of the changing demographics and increased life expectancy. In addition to the classic tumor-related factors for predicting prognosis, individual patient characteristics may be associated with disease-specific mortality and other breast cancer outcomes. Data from observational studies in patients with breast cancer suggest an age-specific association with mortality.The primary aim of this study was to assess disease-specific mortality among different age groups in postmenopausal patients with hormone receptor-positive breast cancer. A secondary aim was to evaluate breast cancer relapse and other-cause mortality in the different age groups. Participants were 9766 patients who had enrolled between 2001 and 2006 in the TEAM (Tamoxifen Exemestane Adjuvant Multinational) trial, a randomized, phase 3, multinational, open-label study. The study subjects were divided into 3 categories based on the age of diagnosis: younger than 65 years (n = 5349), 65 to 74 years (n = 3060), and 75 years or older (n = 1357).A total of 1043 deaths occurred during median follow-up of approximately 5.1 years. Disease-specific mortality, as a proportion of all-cause mortality, decreased with age (<65 years, 77.5%; 65-74 years, 56.3%; >75 years, 36.3%; P < 0.001). Multivariable analysis revealed that, compared with patients younger than 65 years, disease-specific mortality increased with age for patients aged 65 to 74 years [hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.01-1.54] and patients aged 75 years or older (HR, 1.63; 95% CI, 1.23-2.16; P < 0.001). In multivariable analyses, both breast cancer relapse and other-cause mortality were higher in the groups 65 to 74 years and older than 75 years compared with patients younger than 65 years. Breast cancer relapse increased among patients aged 65 to 74 years (HR, 1.07; 95% CI, 0.91-1.25) and patients aged 75 years or older (HR, 1.29; 95% CI, 1.05-1.60; P = 0.06). Similarly, other-cause mortality increased in patients aged 65 to 74 years (HR, 2.66; 95% CI, 1.96-3.63) and in patients aged 75 years or older (HR, 7.30; 95% CI, 5.29-10.07; P < 0.001).These findings show that disease-specific mortality increases with age among postmenopausal women with hormone receptor-positive breast cancer.