Breast cancer & bone health

Why you might develop osteoporosis

Women with breast cancer have an increased risk of developing osteoporosis because of the treatments used in breast cancer. Treatments can impact directly on oestrogen levels (vital for bone strength), and may also cause ovarian failure in premenopausal women, resulting in a further significant fall in oestrogen and a premature/early menopause.

Chemotherapy

Link to osteoporosis:

• Ovarian failure in premenopausal women causes significant fall in oestrogen leading to bone loss, particularly in the spine
• Bone loss in the spine in the first 12 months after chemotherapy is approximately 3-4%
• If ovarian failure does not occur after chemotherapy, bone mineral density tends to remain stable

Impact in postmenopausal women: Chemotherapy given to postmenopausal women does result in loss of bone density.

Medication: Tamoxifen also sold as Nolvadex, Istubal Valodex

Link to osteoporosis:

• Tamoxifen works by partially suppressing the body's production of oestrogen because it has anti-oestrogen effects in the breast but it does not provide enough oestrogen to help the bones of younger women
• Women who take Tamoxifen may experience a progressive loss of bone from the spine of approximately 1.4% per year[1]

Impact in postmenopausal women: Postmenopausal women with breast cancer who take Tamoxifen:

• may have an increase in bone mass in the spine of approximately 1.2% per year
• may have a slightly increased rate of fracture compared to the normal population[2] but more research is needed in this area

Aromatase inhibitors

Aromatase inhibitors are prescribed in Australia for postmenopausal women whose breast cancer has spread beyond the breast and lymph nodes. These drugs work by virtually suppressing all oestrogen production in the body.

Studies using one of these drugs known as anastrozole (sold as Arimidex), has shown a loss of bone density at the spine and hip. This effect seems to be more significant in women who are newly menopausal[3]. There is also a very slightly increased risk of fracture for women taking this medication, although further research is needed in this area.

Treatment

If you have breast cancer and you are diagnosed with osteoporosis, there are specific therapies available, which can treat this condition and your doctor can advise you. It will be important to develop or maintain an exercise plan, which includes weight bearing exercise, and to ensure there is adequate calcium in your diet.

For more information on breast cancer & bone health go to Breast Cancer Network Australia.

** Currently under review **

This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at December 2013.