It is important for women who have been diagnosed with breast cancer to consider having a check in regards to their bone health, especially if they have other risk factors for osteoporosis.

For those women who are diagnosed with osteoporosis, there are specific therapies available which can treat this condition. It is also important to address lifestyle factors such as exercise and ensure that there is adequate calcium in the diet.

Premenopausal Woman and Breast Cancer

Premenopausal women following diagnosis of breast cancer often become menopausal as a consequence of the various treatments for breast cancer and hence undergo a premature menopause. Chemotherapy is frequently given to this group of women and it may lead to ovarian failure, which ultimately results in rapid bone loss particularly at the spine. Bone loss in the spine in the first 12 months after chemotherapy is approximately 3 – 4%.⁸³ Even though bone loss may occur after chemtherapy, it does not necessarily lead to osteoporosis. If ovarian failure does not occur after chemotherapy, bone mineral density tends to remain stable.⁸³

Premenopausal women who are given tamoxifen therapy also experience a progressive loss of bone from the spine of approximately 1.4% per year.⁸⁴ Tamoxifen works by partially suppressing the body’s production of oestrogen, in that it has anti-oestrogen effects in the breast. However, it continues to have oestrogen like effects in bone and thereby should protect the skeleton from bone loss. This apparent contradiction may be because maintenance of bone mass in premenopausal women requires adequate levels of oestrogen and it may be that tamoxifen when given to premenopausal women does not provide sufficient oestrogen like effects in the younger skeleton.  

Post Menopausal Women and Breast Cancer

The effect of cancer treatment on bone in postmenopausal women is slightly different to that of premenopausal women. Chemotherapy given to postmenopausal women does result in loss of bone density.⁸⁵ However, tamoxifen given in this age group results in an increase in bone mass in the spine by approximately 1.2% per year.^84,86 Hence tamoxifen has a desirable effect on bone mass in postmenopausal women. Although, there is some recovery of bone density in postmenopausal women given tamoxifen, a recent report has found that there still is a slight increased rate of fracture in this group compared to the normal population,⁸⁶ despite the increases in bone mineral density. However, more research is needed in this area.

Newer Drug Therapies

There are newer drug treatments, which are available to postmenopausal women who have advanced breast cancer disease (ie breast cancer that has spread beyond the breast and lymph nodes). These drugs known as 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. The studies with one of these drugs known as anastrozole (Arimidex), has shown that it does lead to loss of bone mass at the spine and hip.⁸⁷ This effect seems to be more significant in the women who are newly menopausal.⁸⁷ There is also a very slightly increased risk of fracture for women taking this medication, although further research is needed in this area.⁸⁷

Content updated February 20, 2006