Education For Healthy Life

Breast cancer treatment can lead to accelerated bone loss. Bone loss is a fairly common side effect of long-term estrogen-reducing therapies. Unfortunately, this important problem is not recognized as often as it should be.

To understand the relationship between estrogen, breast cancer, and bone health, it is helpful for patients to know that:
― Estrogen makes bones stronger but can also make breast cancer grow. Estrogen, a hormone made by the body, plays an important role in maintaining good bone health. However, estrogen also makes some kinds of breast cancer grow. These are known as estrogen-receptor positive (ER+) breast cancers. Treatments that interfere with the way estrogen works can help prevent breast cancer tumors from growing and spreading. The problem is that this interference can also lead to accelerated bone loss.


Hormonal therapy and chemotherapy are both breast cancer treatments that can cause bone loss due to their affect on estrogen. Hormonal therapy with aromatase inhibitor drugs such as Arimidex®, Femara®, and
Aromasin® can block the synthesis of estrogen. These drugs are approved by the FDA for the prevention and treatment of metastastic disease. Aromatase inhibitors have been shown to be particularly effective in preventing breast cancer from recurring in post-menopausal women. However, in addition to suppressing estrogen and preventing cancer recurrence in post-menopausal women, aromatase inhibitors can cause especially severe bone loss and increased risk of fractures.

Chemotherapy can also cause bone loss and increase the risk of fracture because of
its effect on estrogen. For example, chemotherapy can cause the ovaries to stop
producing estrogen.