Treatment of Bone Metastases
Treatment of cancer that has spread to the bones often focuses on preventing a tumor from growing or slowing its growth, preventing damage to the bones and relieving symptoms such as pain, fractures, weakness and numbness. With improved treatment techniques and new types of medications, many patients are now able to live longer with metastatic cancer. The specific treatments depend on type of primary cancer, the treatments the patient has already received, the location and amount of cancer and the patient’s overall health. The doctor may recommend any of the following treatments:
Bone-modifying agents
Bone-modifying agents, including bisphosphonates and denosumab, are often used when cancer has spread to the bones. These drugs can strengthen the bones and prevent further bone damage, reducing the risk of pain, fractures and breaks. Bisphosphonates may also prevent thinning of the bone (osteoporosis) and may help decrease hypercalcemia.
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Radiation Therapy
Radiation therapy uses waves of high-energy rays to target and kill cancer cells. Radiation therapy may be given to patients with bone metastases in order to shrink the tumor, relieve pain and ease symptoms. Radiation therapy can help prevent bone fractures by shrinking the tumor before it destroys too much bone. For patients whose cancer has spread to the spinal cord, radiation therapy can shrink the tumor before it grows large and presses on nerves. The nerves in the spinal cord help control different parts of the body, and a tumor pressing on these nerves can cause weakness, numbness, constipation and difficulty urinating. Once these symptoms occur, they are very difficult to reverse.
Chemotherapy
Chemotherapy uses drugs that travel through the bloodstream and attack rapidly dividing cells, such as cancer cells. It may be given through the vein (intravenously) or by mouth (orally). Chemotherapy is often one of the main treatments for patients with metastatic disease, as these drugs travel throughout the entire body targeting rapidly dividing cells. Chemotherapy can target cancer cells that have spread from the original tumor site to other parts of the body, such as the bones. This therapy can shrink tumors and relieve symptoms but does not cure the disease.
Surgery
If cancer has spread to the bone, surgery may be recommended to remove the tumor, relieve symptoms, treat fractured bones, and/or to stabilize the bone to prevent fractures. The doctor may insert metal rods, plates, screws and other immobilization devices to stabilize the bone and prevent a fracture. A fast-acting bone cement may also be injected.
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Hormone Therapy
Hormone therapy may be a very effective treatment for certain types of cancers that spread to the bone, such as breast cancer and prostate cancer.
- Some women have breast cancer that is estrogen-receptor positive. In these women, the estrogen hormone may cause the tumor to grow more aggressively. Hormone therapy blocks the effect of estrogen or lowers its levels, preventing the hormone from fueling cancer growth.
- Prostate cancer is usually hormone-sensitive, meaning that male hormones such as testosterone cause the cancer to grow more aggressively. Hormone therapy blocks the production of testosterone and prevents it from fueling cell growth. Doctors often use hormone therapy to treat late-stage prostate cancer and about one in every three men with prostate cancer need this treatment.
Radiopharmaceuticals
Radiopharmaceuticals are a type of treatment that uses radioactive substances to treat cancer that has spread to the bone. These medications are given intravenously and travel throughout the body, collecting in the areas of bone where the cancer is located. Radiopharmaceuticals then give off radiation to destroy the tumors. Additionally, patients with metastatic thyroid cancer may be given radioactive iodine therapy. The patient ingests high doses of radioactive iodine, which collects in the thyroid and in thyroid cancer cells in other parts of the body. This treatment can destroy thyroid cancer cells that have spread to different parts of the body.
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Immunotherapy
Cancer immunotherapy is a type of treatment that harnesses the patient’s immune system to attack and destroy tumor cells. Different types of immunotherapy may be recommended depending on the location of the primary tumor.
- For lung cancer that spreads to the bones, the doctor may recommend treatment with an immune checkpoint inhibitor that targets the PD-1 protein. The immune system has checkpoints to keep it from attacking normal cells in the body and cancer cells can use these checkpoints to avoid being destroyed by the immune system. These medications target the checkpoints, allowing the immune system to attack the cancer cells.
- For prostate cancer that spreads to the bones and has stopped responding to initial treatments, the doctor may recommend vaccine therapy. The vaccine boosts your immune system's ability to fight prostate cancer cells. This treatment does not cure the disease, but may help men with advanced disease live longer. The vaccine is developed for each patient specifically by removing some white blood cells, exposing the cells to a protein from prostate cancer, and then re-injecting them back into the patients' bloodstream.
- Immunotherapy used to be the primary treatment for advanced kidney cancer, but because it has serious side effects and only benefits a small minority of patients, many doctors use this treatment less. Your doctor may or may not recommend immunotherapy with IL2 for advanced kidney cancer. If this doesn't work, your doctor may explore targeted therapies.
Targeted Therapy
Targeted therapies or precision medicines are designed to block a specific target, usually a protein or genetic change, that can influence the growth and development of cancer cells. Since targeted therapies directly attack the cancer cells, they tend to have less side effects than traditional medications such as chemotherapy, which target all rapidly-dividing cells. The three main types of targeted therapy are small-molecule drugs, monoclonal antibodies, and anti-angiogenesis therapy.
- Small-molecule drugs can enter cancer cells and target certain proteins and enzymes that are involved in key cell functions such as growth and division. Small-molecule drugs can block these substances, and prevent them from stimulating tumor growth.
- Monoclonal antibodies function very much like the antibodies that the body produces naturally in response to infection and disease. Monoclonal antibodies bind to harmful substances in the body, such as cancer cells, viruses, and bacteria, and signal the body's immune system to find and destroy the harmful substances.
- Angiogenesis is the process by which tumors create new blood vessels to support their growth. Anti-angiogenesis therapy attacks this process, preventing the growth of new blood vessels.
For breast cancer, the doctor may recommend therapies that target the HER2 protein. For lung cancer, drugs that target the EGFR protein may be recommended. For thyroid cancer, TKI inhibitors and anti-angiogenesis drugs may be recommended. For advanced kidney cancer, anti-angiogenesis therapy is often the primary treatment. If this therapy does not work, monoclonal antibodies that target the PD-1 protein may be used.
Palliative Care
Palliative care is any form of treatment given to cancer patients to relieve symptoms and side effects of the disease and improve quality of life. The goal of palliative care is not to cure the disease, but to make the patient as comfortable as possible throughout their journey with cancer. Palliative care is an important treatment for cancer that has spread to the bones. Palliative treatments for bone metastases may include surgery and radiation therapy to shrink and remove tumors in order to relieve symptoms. Palliative treatments to improve your physical comfort may include pain or anti-nausea medication to combat the symptoms and side effects of cancer and its treatments. Palliative care also includes any help dealing with the emotional and spiritual issues surrounding a cancer diagnosis, as well as practical concerns such as legal and financial questions.
Clinical Trials
Clinical trials allow patients to try a new treatment before it is available to the general public. In some cases, this may be a new drug that has not been used in humans before, or it may be a drug or drug combination that is not currently used for that specific type of cancer. Early phase clinical trials are often used to test side effects of a drug or drug combination, while later phase clinical trials are used to see how effective a new treatment might be for a certain type of cancer. Clinical trials allow doctors and researchers to improve the treatment of cancers with possibly more effective therapies. A clinical trial may be a new, groundbreaking drug or it may have no effect. It is important to talk with your doctor about the pros and cons of clinical trials for your particular situation.
