When Prostate Cancer Spreads to the Bones
Prostate cancer begins in the gland between the bladder and rectum. But often, cancerous cells break off and spread through the surrounding tissue, blood vessels and the lymphatics. This is a condition called metastasis. If your prostate cancer spreads to distant parts of your body, it usually strikes your bones next. In fact, more than two out of three cases of metastatic prostate cancer affect the bones.
Bone metastasis may cause severe pain and a decrease in your quality of life. If your cancer is advanced, preventing or slowing the growth of cancer in your bones will soon become a major focus of your treatment. Treating bone metastasis can help prevent or reduce other risks, including fractures and high blood calcium (also called hypercalcemia), which can cause coma or kidney damage.
Bone metastasis is serious, but treatment can help stop further damage to your bones and improve your symptoms. Medications, other cancer therapies such as radiation, and taking steps to prevent falls may ease your pain and protect your skeleton.
Symptoms Point to Cancer's Spread
Bone pain is often the first sign your cancer has extended into your bones. For instance, a man may experience lower back pain from cancer that has spread into his pelvis.
Sometimes a fracture in your arms, legs, or spine is the first sign that your cancer has spread. You may break a bone when you fall or just during your regular daily activities. If you do, you'll feel sudden, severe pain. Get immediate treatment—especially if the pain strikes in your back, a sign of a broken bone in your spine.
In other cases, bone metastasis has no symptoms at all.
Tests Detect Tumors in Your Bones
Your doctor may check you for bone metastasis if you have warning signs, or as part of the process of determining how far your cancer has progressed. Tools he or she may use include:
Imaging tests, including X-rays, bone scans, magnetic resonance imaging (MRI), and computed tomography (CT) scans
Urine tests, which can find substances that are released when bone is damaged
Biopsies, when your doctor takes a sample of your tissue and looks at it under a microscope
Blood tests to check for high calcium levels or other chemicals that indicate your cancer has spread. This includes testing for prostate-specific antigen, or PSA. PSA levels are usually higher when you're first diagnosed with prostate cancer, but then decrease during treatment. If they increase again, it may indicate a recurrence of cancer.
When your doctor tells you the stage of your prostate cancer, he or she will use three letters: T (for the extent of the main tumor), N (to indicate whether it has spread to nearby lymph nodes), and M. The "M" category describes whether your cancer has spread to distant parts of your body. If you have bone metastasis, your cancer is in stage M1b, and if your cancer has also spread to another organ, it is stage M1c.
Medications, Radiation Treat Your Bones
If your doctor finds bone metastasis, you will most likely be treated with a type of medication called a bisphosphonate. Given through an intravenous (IV) line, bisphosphonates protect your bones from further damage, reduce pain, lower blood calcium levels, and prevent fractures and other complications. They can also help strengthen your bones if they've been weakened as a side effect of hormone therapy for prostate cancer.
At Your Appointment
What to Ask Your Doctor About Prostate Cancer
Your doctor will most likely tell you to take vitamin D and calcium in addition to bisphosphonates. This prevents your calcium level from dropping too low.
A newer drug called denosumab (Xgeva, Prolia) also prevents fractures and may strengthen your bones, and corticosteroids may help relieve bone pain. Radiopharmaceuticals, medications that are injected into your veins, emit radiation that kills cancer cells. They have been shown to help four out of five men with painful bone metastasis from prostate cancer.