When prostate cancer cells spread to the bone, it’s known as prostate cancer bone metastases (not bone cancer). Once the cells settle in the bone, they start to interfere with the bone’s normal health and strength, often leading to bone pain, fracture, or other complications that can significantly impair a man’s health.
Early detection of bone metastases can help determine the best treatment strategy. It can also help ward off complications. Because men with prostate cancer bone metastases often experience painful episodes, pain management and improving quality of life are important aspects of all treatment strategies.
Treatment with bisphosphonates or denosumab can help prevent complications related to bone metastases, like fractures. Bisphosphonates are drugs that are designed to help reset the balance in the bone between bone growth and bone destruction which is disrupted by the prostate cancer bone metastases.
Zoledronic acid (Zometa) is a bisphosphonate that can delay the onset of complications associated with prostate cancer bone metastases and relieve pain. It is typically given once every three weeks as a 15-minute infusion. Less frequent schedules are sometimes used as well depending on your individual circumstance and risk.
Denosumab (Xgeva) is a different type of bone-targeting drug which is given as an injection, rather than an infusion, and may be used instead of a bisphosphonate.
There are some risks with both classes of bone-targeted agents, including something called osteonecrosis of the jaw (ONJ) that can occur after deep dental procedures and extractions or sometimes spontaneously. This results in sometimes jaw pain and poor healing of your teeth. Certain laboratory assessments must be monitored with regular use of either medication. Daily calcium and vitamin D are supplements are typically recommended, and you should discuss this with your doctor.
Painful bone metastases can commonly be treated successfully with external beam radiation therapy. This generally involves 1-2 weeks of daily radiation treatments and can significantly improve symptoms. Sometimes radiation therapy may be recommended if there is an area of the bone (typically in the hip or leg) which looks like it may easily break, even if it is not currently painful. The goal in that case is to reduce the risk of developing a fracture. This kind of radiation targeted to sites of painful metastases can usually be safely given, even if you received radiation to treat your initial prostate cancer.
If there are multiple spots e involved, medications called radiopharmaceuticals are often used. These radioactive isotopes home in on the bone and the cancer and can reduce pain in multiple spots all at once. The most commonly used therapies include Samarium-153 and Strontium-89 – both treatments have been shown to effectively relieve pain from cancer metastases. There is some evidence that these therapies may also prevent new sites of bone metastases from developing. These drugs do not prolong life, however, and their use is limited due to the fact that they can severely lower the blood counts.
A newer radiopharmaceutical called Radium-223 (Alpharadin) has been developed which has both increased effectiveness and decreased toxicity. In the ALSYMPCA trial of men with advanced prostate cancer metastatic to bone, both symptoms and the incidence of new metastases were improved relative to placebo. Notably, an improvement in overall survival was also seen in all subgroups analyzed. Talk to your doctor about whether this treatment is appropriate for you, and if so, where you can get it.
Complementing radiation treatments with medications (opiates, non-steroidal anti-inflammatory medications), alternative medicines (acupuncture, healing touch, yoga, biofeedback), and psychological and social support is recommended.
Chemotherapy can also be highly effective in reducing bone pain. Bisphosphonates like zoledronic acid have also been shown to reduce pain and fractures from skeletal metastases and can complement existing therapies.