Breast cancer and osteoporosis - management of cancer treatment-induced bone loss in postmenopausal women with breast cancer

Abstract

The incidence of breast cancer (BC) in postmenopausal women is continuously rising. Due to early diagnosis and various treatment designs, the long-term clinical outcome has improved. Frequent settings are chemotherapy as well as endocrine treatment. Both have proven to interfere with bone health resulting in cancer treatment-induced bone loss (CTIBL). Whereas chemotherapy is associated with increased bone resorption, aromatase inhibitor (AI) therapy reduces residual estrogen and is associated with decreased bone mineral density. Independent of the AI administered, the loss of bone mineral density is twice as high compared to healthy postmenopausal women. As a consequence of CTIBL, both chemotherapy and AI treatment can lead to a significantly increased fracture risk. Therefore, several guidelines have emerged for the management of CTIBL in women with BC, including strategies to identify and treat those at high risk for fractures. Further research on tracking guideline adherence examining the feasibility and practicability of guideline implementation to bridge the gap between determined scientific best evidence and applied best practice is needed to adjust these guidelines in the future.

Keywords: AIBL; Aromatase inhibitor-induced bone loss; Bone mineral density; Breast cancer; CTIBL; Cancer treatment-induced bone loss; Osteoporosis.

Fig. 1

Influence of treatment with aromatase inhibitors on bone mineral density (BMD) [54].

Fig. 2

Influence of treatment with aromatase inhibitors on fracture risk (data not from direct comparison) [54].

Fig. 3

International guideline for managing bone health during cancer treatment [12] (BMI = Body mass index). ^aIncludes aromatase inhibitors and ovarian suppression therapy/oophorectomy for breast cancer, and androgen deprivation therapy for prostate cancer. ^bIf patients experience an annual decrease in bone mineral density (BMD) of ≥ 10% (or ≥ 4–5% in patients who were osteopenic at baseline) using the same DXA machine, secondary causes of bone loss such as vitamin D deficiency should be evaluated and antiresorptive therapy initiated. Use lowest T-score from spine and hip. ^c6-monthly intravenous zoledronic acid, weekly oral alendronate or risedronate or monthly oral ibandronate acceptable. ^dDenosumab may be a potential treatment option in some patients. ^eAlthough osteonecrosis of the jaw is a very rare event with bone-protective doses of antiresorptives, regular dental care and attention to oral health is advisable.