A new Position Statement, appearing in the Journal of Bone Oncology and jointly published by seven international and European organizations, identifies fracture-related risk factors in patients treated by aromatase-inhibitors (AI) and outlines key management strategies to help prevent bone loss and related fractures.
The Statement is authored by experts from the International Osteoporosis Foundation (IOF), Cancer and Bone Society (CABS), International Expert Group for AIBL (IEG), European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO), European Calcified Tissue Society (ECTS), International Menopause Society (IMS), and the International Society for Geriatric Oncology (SIOG).
Women receiving adjuvant AI therapy for breast cancer experience a two- to four-fold increase in bone loss compared to the normal rate of bone loss with menopause – and as a result they are at heightened risk of fracture.
Professor René Rizzoli, Chairman of the IOF Bone and Cancer Working Group, stated: "While clinical trials have shown an approximately 10% increase in absolute fracture risk for women on AI therapy, other real-world studies indicate that the fracture risk may be significantly higher. Additionally, breast cancer patients hospitalized for a bone fracture showed a higher risk of death compared to breast cancer patients without a bone fracture. These are compelling reasons to ensure that all women on AI therapy for breast cancer receive early assessment and treatment."
Among its conclusions, the Position states:
In all patients initiating AI treatment, fracture risk should be assessed and recommendations given in regard to exercise and calcium/vitamin D supplementation.
Bone-directed therapy should be recommended for the duration of AI treatment to all patients with a T-score <-2.0 SD, or with a T-score of <-1.5 SD with one additional risk factor, or with two or more risk factors (without BMD).
Patients with a T-score > - 1.5 SD and no risk factors should be managed based on BMD loss during the first year, and based on local guidelines for postmenopausal osteoporosis.
Based on current evidence, six monthly denosumab or yearly zoledronate for the duration of AI therapy is recommend for the prevention of AIBL in postmenopausal women receiving adjuvant AI therapy, with zoledronate recommended when effects on disease recurrence are the priority, and denosumab when fracture risk is the dominant concern.
Because of the decreased incidence of bone recurrence and breast cancer specific mortality associated with bisphosphonate use, adjuvant bisphosphonates are recommended for all postmenopausal women at significant risk of disease recurrence.
Compliance should be regularly assessed as well as BMD after 12-24 months on treatment.
Professor Peyman Hadji, first author of the paper and board member of the Cancer and Bone Society, added: "As fragility fractures often result in prolonged disability and loss of independence, it is important that women who are being treated for hormone-sensitive breast cancer are managed to prevent bone loss and related fractures. As well, given that recent research has revealed the potential anticancer benefits of antiresorptive agents in early breast cancer, these agents can also play a role in preventing disease recurrence."
The authors note that in addition to the established risk factors used in the Position Statement's bone health algorithm, other potential fracture risk factors in women with breast cancer include chemotherapy, radiotherapy, low weight, and family history of hip fractures. Further studies examining the role of these factors are encouraged and annual assessment of breast cancer patients with these potential risk factors may be prudent.
Journal of Bone Oncology, June 2017
The International Osteoporosis Foundation (http://www.iofbonehealth.org)