Health-related quality of life in long-term breast cancer survivors: differences by adjuvant chemotherapy dose in Cancer and Leukemia Group B study 8541.
Background: The Survivor's Health and Reaction (SHARE) study examined health-related quality of life (HRQL) in breast cancer patients who had participated in Cancer and Leukemia Group B Trial 8541 from 1985 to 1991.
Methods: In total, 245 survivors (78% of eligible patients) who were 9.4 to 16.5 years postdiagnosis (mean, 12.5 years postdiagnosis) completed HRQL surveys relating to 5 domains. Analyses examined HRQL domains according to 3 different chemotherapy dose levels that were administered in the original treatment trial: low-dose cyclophosphamide, doxorubicin, and fluorouracil (CAF) at 300 mg/m(2), 30 mg/m(2), and 300 x 2 mg/m(2), respectively, over 4 cycles; standard-dose CAF at 400 mg/m(2), 40 mg/m(2), and 400 x 2 mg/m(2), respectively, over 6 cycles; and high-dose CAF at 600 mg/m(2), 60 mg/m(2) and 600 x 2 mg/m(2), respectively, over 4 cycles.
Results: In univariate analyses, a statistically significant difference was observed on the Medical Outcomes Study 36-item short form Physical Role Functioning subscale by treatment group, with lower mean scores in the standard treatment arm (mean, 65.05) compared with mean scores in the low-dose arm (mean, 74.66) and the high-dose arm (mean, 84.94; P.0001). However, multivariate analysis revealed that treatment arm no longer was statistically significant, whereas the following factors were associated with decreased physical role functioning: age >or=60 years (odds ratio [OR], 3.55; P = .006), increased comorbidity interference total score (OR, 1.64; P = .005), lower vitality (OR, 1.05; P = .0002), and increased menopausal symptoms (OR, 1.04 P = .02).
Conclusions: At 9.4-16.5 years after their original diagnosis, differences in physical role functioning among breast cancer survivors who had received 3 different dose levels of chemotherapy were explained by clinical and demographic variables, such as age, fatigue, menopausal symptoms, and comorbidities. Prospective studies are needed to further assess the role of these factors in explaining HRQL and physical role functioning among long-term survivors.