The fracture risk assessment tool (FRAX) was developed to predict an individual’s 10‐year probability; of major osteoporotic fracture and hip fracture from readily assessed clinical risk factors (age, sex, body mass index [BMI]; dichotomized risk factors comprising prior fragility fracture, parental history of hip fracture, current tobacco smoking, ever use of long‐term oral glucocorticoid use, rheumatoid arthritis, high alcohol intake, recommendations, making it the most widely used fracture prediction tool worldwide.
Women with hormone receptor
Although initially developed for use in the general population; there is increasing interest in the application of FRAX to individuals with special conditions. Breast cancer is the most common cancer of women globally. AI therapy is to reduce the risk of cancer recurrence in postmenopausal women with hormone receptor-positive; breast cancer but has reported increasing bone turnover, bone loss, and fracture risk.
Concomitant bisphosphonate therapy and more recently denosumab are therapeutic options to prevent bone loss in AI users. Although one position paper has offered guidance on prevention of bone loss and fractures in postmenopausal women treated with AI for breast cancer that incorporates FRAX in the algorithm; the authors highlight concerns that FRAX was not designed to assess fracture risk in this setting and its accuracy is unknown.
Therefore given the uncertainty regarding the application of FRAX in AI users; they examined the performance of FRAX in routine clinical practice using a large clinical registry of BMD results for the province of Manitoba, Canada. This registry allowed us to identify and compare women initiating AI therapy for breast cancer, women with breast cancer not receiving AI therapy, and women from the general population without breast cancer.
Determining fracture risk
The FRAX tool takes into account certain factors to determine the risk of bone fracture in the general population. In a Journal of Bone and Mineral Research study; the tool was effective at determining fracture risk for women with breast cancer who treated with aromatase inhibitors; which cause accelerated bone loss when combined with bone mineral density measurements.
However, the results also question the practice of considering aromatase inhibitors a “secondary cause of osteoporosis” when the FRAX tool is used without bone mineral density; because this can lead to overestimation of fracture risk. Nonetheless, it is very important to determine fracture risk in women receiving aromatase inhibitor therapy; who will most likely experience bone loss during treatment.
“They hope that our data will help to inform clinical guidelines regarding fracture risk assessment in women with breast cancer; and the incorporation of FRAX in management algorithms of those receiving aromatase inhibitors,” said lead author Dr. William D. Leslie, of the University of Manitoba, in Canada.