Prostate Cancer: Drugs Commonly Used In Treating Bone Metastasis

If prostate cancer spreads (metastasizes) beyond the prostate gland it can spread into nearby tissues or lymph nodes. Once this occurs, prostate cancer will almost always spread into a patient’s bones. Bone metastasis can often be painful and can cause other problems, such as fractures (breaks) or high blood calcium levels, which can be dangerous or even life threatening. The goal of treatment is to control the spread and relieve the pain of cancer has already reached the bones.

Bisphosphonates

Bisphosphonates are a class of drugs used to help relieve pain and high calcium levels caused by cancer that has spread (metastasized) to the bones. These drugs essentially work by slowing down bone cells called osteoclasts which can normally break down the hard mineral structure of bones that help to keep them healthy. For patients with prostate cancer, the most commonly used bisphosphonate is zoledronic acid (Zometa). The drug is administered to the patient intravenously (IV) typically once every 3 or 4 weeks. To prevent any potential issues with low calcium levels patients undergoing treatment are advised to take supplements containing calcium and vitamin D.

Side Effects

• Fever and flu like symptoms
• Fatigue
• Digestive problems
• Increased bone and joint pain
• Can potentially cause kidney damage
• In very rare instances use of bisphosphonates can cause osteonecrosis of the jaw (ONJ). Osteonecrosis is a condition in which a portion of the jaw bone loses its blood supply and dies. The result of which can lead to tooth loss, infections and open sores of the jaw bone that are difficult to treat.

Denosumab

Denosumab (Xgeva, Prolia), like the bisphosphonates, is another drug that is used when prostate cancer spreads to bone. Denosumab also blocks the bone cells called osteoclasts, but it accomplishes this in a much different fashion. In patients whose cancer has already spread into the bones,denosumab can help to prevent or delay additional complications such as bone fractures. The drug is administered by an injection under the skin every 4 weeks and as with bisphosphonates patients are advised to take a supplement containing calcium and vitamin D to prevent problems with low calcium levels.

Side Effects

• Nausea
• Red, dry, or itchy skin
• headache
• muscle or joint pain.
• Diarrhea
• Fatigue
• In very rare instances, as with the use of bisphosphonates, can cause osteonecrosis of the jaw (ONJ).