What happens if I develop bone pain?
When prostate cancer metastasizes, it tends to travel to the pelvic lymph nodes first and then to the bones. Bone metastases may be silent, meaning that they do not cause any pain, or they may be symptomatic, causing pain or leading to a fracture. Bone metastases are typically identified on a bone scan and can also be seen on a plain X-ray.
There are many ways to treat bone pain. Your doctor will likely try the simplest treatments and those associated with the least side effects first, and then progress as needed. Nonsteroidal anti-inflammatories, such as ibuprofen, are typically used as a first-line treatment. If the pain is not controlled with these, then narcotics, such as Tylenol with codeine, are added. For patients with a localized bone metastasis that is causing persistent discomfort, localized radiation therapy may be used
(XRT is not useful for men with multiple bone metastases). XRT provides pain relief in 80 to 90% of patients, and the relief may last for up to 1 year in slightly more than half of these men. Usually, the total radiation dose is given over 5 to 15 quick treatment sessions.
When multiple painful bone metastases are present, hemibody radiation may be used. Because this therapy affects a larger area of the body, there are more side effects, including lowering of the blood pressure (hypotension), nausea, vomiting, diarrhea, lung irritation, hair loss, and lowering of the blood count. Hemibody radiation is also given over several treatment sessions. It can lead to pain control that lasts up to one year in as many as 70% of individuals.
Another form of therapy for multiple painful bone metastasis is radioisotope therapy. With this form of therapy, a radioisotope, a chemical with a radioactive component, is injected into a vein. The chemicals used preferentially go to bone that is affected by cancer. These chemicals are picked up by the bone and radiate the area. Two such agents are strontium 89 and samarium 153.
Strontium 89 is a chemical similar to calcium and tends to concentrate in areas of the body where calcium is absorbed, such as bone, and it preferentially goes to areas of bone metastases. Only a small amount of the injected dose remains in the bones after 1 week and most is eliminated in the urine. For this reason, it is important to carefully dispose of urine for the first week after injection. The strontium 89 that is picked up by the bones will exert its radiation effect for as many as 50 days, whereas in normal bone it is effective for only about 14 days. During this time, you are not considered a radiation hazard to friends or family.
Another form of therapy for multiple painful bone metastasis is radioisotope therapy.
Strontium 89 (Metastron) improves bone pain in 80 to 86% of individuals, and relief starts about 2 weeks after treatment. However, pain relief may be preceded by an initial increase in pain. Strontium 89 has also been used in combination with EBRT. In patients receiving both therapies, there is no apparent increase in survival. Those who receive the combination therapy have a decreased need for pain medications and an increase in physical activity, fewer sites of new bone pain requiring palliative EBRT, and larger decreases in PSA. Studies are being performed to evaluate the effect of combining strontium 89 with various forms of chemotherapy, such as doxorubicin (Adriamycin).
Because strontium 89 does affect normal bone, albeit to a lesser degree than that affected by prostate cancer, blood counts must be monitored because the bone is responsible for producing the blood cells. Typically, the blood counts are checked twice a week, but more frequently if needed. If the platelet and white blood cell counts are stable, you may be retreated with strontium 89, if needed.
Another radioisotope is samarium 153 (Quadramet). It is a newer agent that is also administered intravenously. It has been shown to be effective in decreasing bone pain and produces a mild decrease in the blood count.
Biphosphonates are chemicals that interfere with bone breakdown and are typically used for treatment of osteoporosis. Most prostate cancer bone metastases are not lytic metastases (i.e., they do not cause bone breakdown), but some bone breakdown does appear to occur; biphosphonates lead to improvement in bone symptoms in men with prostate cancer. Their use in bone pain remains investigational.