Incidence of joint symptoms and bone fractures in Japanese postmenopausal breast cancer patients treated with adjuvant anastrozole
Incidence of joint symptoms and bone fractures as well as changes in bone mineral density (BMD) in Japanese postmenopausal breast cancer patients treated with adjuvant anastrozole were investigated to determine whether there is an ethnic difference from Caucasian patients in the incidence of these adverse events of anastrozole. Adjuvant anastrozole was used to treat 348 postmenopausal breast cancer patients for a median period of 22 months. Adverse events of anastrozole including joint symptoms, loss of BMD, and bone fracture were investigated by means of chart review. Joint symptoms developed in 96 (27.5%) patients. Age (younger than 65) and prior chemotherapy was strongly associated with an increased risk of joint symptoms. Annual fracture incidence was 0.86 and 0.85% and lumbar BMD decreased by 1.3 and 2.8% at 1 and 2 years, respectively. In comparison, the ATAC trial reported corresponding figures of 2.0 and 2.7 and of 2.2 and 4.0%. Incidence and risk factors of joint symptoms are similar for Japanese and Caucasian patients, but the former tend to show a smaller decrease in BMD and a lower incidence of bone fractures, probably due to ethnic difference in the hormonal milieu.