Bone mineral density and FRAX as predictors of fracture risk in women with breast cancer.

Abstract

121 Background: The number of cancer survivors is rising in the USA, the 2007 CDC analysis of the SEER database estimated 11 million cancer survivors, with 90% being over the age of 65 years. Of these, 70% are women, and the most common cancer in survivors is breast cancer. Cancer therapy induced bone loss (CTIBL) contributes to an increase in fracture risk in women with breast cancer. Fractures are responsible for considerable morbidity, disability, hopitalizations and mortality in older adults. Fractures are often the cause for nursing home placement in seniors. Our objective was to analyze the prevalence of fractures after breast cancer therapy and to assess the effect of cancer therapy, clinical risk factors, bone density and the World Health Oragnization (WHO) fracture risk assessment [FRAX] as predictors of fracture occurrence. Methods: The study population consisted of breast cancer patients with invasive breast cancer who participated in a genetic databank within a NCI-Comprehensive Cancer Center. Demographic and clinical characteristics were abstracted from the EMR. Participants were followed for 6-12 years. Results: A total of 439 women with breast cancer were assessed; 79 had sustained fractures during the observation period (116 fractures), fractures occurred at multiple skeletal sites in 27 cases. The prevalence of fractures was 18%. Baseline characteristics revealed that women who sustained fractures were mostly Caucasian (91%, p=0.08), and had a family history of osteoporosis (36.9%, p=0.03). The time to fracture was 4.0 years (range 0-12 years) from diagnosis. Fracture cases had lower BMD at the femoral neck 0.86 ± 0.13 gm/cm2 (T-score= -1.0, p=0.04) than non- fracture cases, although BMD was in the low normal range. Eight cases of hip fractures were identified with a median age of 55 years (32-67 years) Median T-score -0.75. Cox proportional hazard analysis failed to identify any specific risk factors for fractures. Conclusions: Fractures occur shortly after commencing cancer therapy. BMD and FRAX risk calculation were not able to identify women who fractured. Occurrence of fractures in breast cancer raises the possibility of cancer-induced impairment in bone quality.