Influence of chemotherapy and endocrine treatment on fractures in postmenopausal women with breast cancer – a retrospective cohort study

Due to a significant increase in the overall survival of women with breast cancer (BC), preventing the long-term consequences of BC treatments is of the utmost importance. Treatments such as aromatase inhibitors (AI), chemotherapy (CHT), and tamoxifen (TAM) may lead to accelerated bone loss and increased fracture risk. The aim of this retrospective cohort study was to evaluate the treatment-induced fracture risk in a large cohort of postmenopausal women with or without BC. It included 4,115 women with BC and 4,115 healthy women from the Disease Analyzer database (IQVIA). Women with breast cancer were matched 1:1 to women without BC with regard to age, index year, and physician. Within 5 years of the index date, 25.3% of women with BC and 14.6% of healthy women sustained fractures. In this study, aromatase inhibitor therapy was significantly associated with a higher incidence of fractures compared to healthy women who had not undergone such therapy (HR: 3.36, p<0.001). In conclusion, postmenopausal women with BC who receive AI treatment exhibited an increased incidence of fractures when compared to the healthy cohort, while treatment with TAM or CHT showed no such association.