Bone-directed drugs

Bisphosphonates for early breast cancer

Bisphosphonates are a class of drugs used to treat abnormally high blood calcium (hypercalcemia) and bone pain caused by some types of cancer which have spread to the skeleton.

In breast cancer, bisphosphonates are also used to reduce bone thinning (osteoporosis) and the risk of fracture among postmenopausal women.

Recently, it was shown that using these drugs after surgery for early breast cancer could reduce the risk of secondary spread and improve long term cure rates. The benefit, however, is only apparent in postmenopausal ladies.

Consequently, postmenopausal patients at significant risk of breast cancer recurrence are now offered bisphosphonate treatment. This usually takes the form of an intravenous drug, zoledronic acid, given 6-weekly for 3 treatments in parallel with chemotherapy and then 6-monthly for 3 years thereafter.

Patients unable to tolerate the intravenous drug may be treated with tablets instead.

Very rarely, patients on bisphosphonates develop a jaw problem known as osteonecrosis of the jaw, so it is important to have a thorough dental check-up before treatment starts and avoid having dental work done within 8 weeks of treatment.

You may also need to take calcium and vitamin D supplements with zoledronic acid to maintain a normal calcium level in the blood. These will be prescribed for you if required.

Denosumab for secondary breast cancer

In patients with breast cancer that has spread to the bones, treatment with denosumab reduces bone pain, lowers the incidence of fractures and excess levels of calcium in the blood and also seems to slow down the rate of spread of breast cancer in the bones.
The drug is given as an injection into the skin, every 4 to 6 weeks, and works by slowing down the breakdown of bone.

Like zoledronic acid, denosumab can also cause osteonecrosis of the jaw so it is important to follow the dental precautions described above.

You may also need to take calcium and vitamin D supplements with denosumab to maintain a normal calcium level in the blood. These will be prescribed for you if required.

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