New research shows that women taking Aromatase Inhibitors (AIs) as part of their breast cancer treatment have a two to four fold increase in bone loss compared to the usual rate associated with menopause.

AIs are often prescribed for women with hormone-receptive breast cancer and work to block the production of oestrogen in post-menopausal women.

The research, published in the Journal of Bone Oncology, has prompted a range of organisations to update their advice to women taking AIs as part of breast cancer treatment to help prevent bone loss and related fractures.

A new Position Statement, jointly published by seven international and European organisations, identifies fracture-related risk factors in patients treated with AIs and outlines key strategies to manage the issue.

Professor René Rizzoli, Chairman of the International Osteoporosis Foundation, says the new research means updated guidelines are needed. 

"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 hospitalised 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."

Auckland-based oncologist, Dr David Porter, agrees that the research highlights an important issue for women taking AIs.

“For women on aromatase inhibitors, treatment with a bisphosphonate (a drug that prevents the loss of bone mass) is an option that should be actively considered as a way of averting bone loss, and potentially reducing the risk of future risk of breast cancer relapse also,” he says.

The research also detailed other risk factors which could increase the likelihood of fractures, including chemotherapy, radiation therapy, a family history of hip fractures, and low weight.

Among other things, the new Position Statement recommends:

  • Facture risk should be assessed in all patients initiating AI treatment and recommendations made in regard to exercise and calcium/vitamin D supplementation
  • Bone retention therapy for some patients with low bone mineral density scores
  • Using adjuvant bisphosphonate for post-menopausal women who are at risk of breast cancer recurrence.

Study author, Professor Peyman Hadji, says fractures can have a major impact on the lives of women treated with AIs for breast cancer.

"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 anti-cancer benefits of antiresorptive agents (such as bisphosphonates or selective estrogen receptor modulators) in early breast cancer, these agents can also play a role in preventing disease recurrence."

Dr Porter says the research is also relevant when determining the hormone or endocrine therapy options for pre-menopausal women.

“These results are also relevant to premenopausal women embarking on ovarian suppression and an aromatase inhibitor, in whom the rate of bone mineral loss is also expected to be significant. 

“In both pre and post-menopausal women they emphasise the importance of careful selection of both the type and duration of endocrine therapy, as there are some women for whom tamoxifen may be a better choice for either part or whole of their endocrine therapy, as it does not have the same long term skeletal health implications, whereas others would be better off with an aromatase inhibitor,” he says.

Further studies examining the role of these factors are encouraged and annual assessment of breast cancer patients with these potential risk factors was recommended.

You can read the full paper here.

7 June 2017

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