Cancer in the bones of the legs, hips, or arms can weaken and destroy their structure and strength. This makes these bones more likely to break, even without a fall or other injury.
Surgery for bone metastases
If a bone in the leg or arm is seriously weakened and is at risk for fracture at any moment, an orthopedic surgeon may recommend placing a metal rod in the weak area. This will give the bone strength and reduce the chance of it breaking. If a weight-bearing bone such as a hip or leg bone has already broken, then a stabilizing device is usually surgically placed. Then your doctor will treat the area with radiation. This radiation will destroy the cancer so the bone can heal. Bone cannot rebuild and strengthen itself if cancer cells are in the way.
Less commonly performed surgeries for bone metastasis include kyphoplasty and vertebroplasty (injecting bone cement into cracks). Kyphoplasty is slightly different because a balloon is inserted first to widen the space inside the crack.
Bone-strengthening medications for bone metastases
If you have bone tumors, a bone-strengthening medicine can help prevent bone breaks and relieve pain. Your doctor may prescribe either Aredia (chemical name: pamidronate disodium) or Zometa (chemical name: zolendroic acid). These medicines are called bisphosphonates. Both are put into your blood with a needle drip (intravenously) into the arm. These drugs can:
- relieve bone pain
- help strengthen bones
- lower the risk of osteoporosis
- lower the risk of spinal cord compression
- lower the risk of breaking a bone weakened by the tumor
- lower high levels of calcium in the blood
These medications are associated with a rare side effect called osteonecrosis of the jaw, which might cause problems for people having dental work. If you have dental problems while taking one of these medicines, be sure to let your dentist know that you're taking this kind of medicine. It's also important for your dentist to know about special care considerations.
Aredia and Zometa can reduce how well the kidney functions over time, but these changes are reversible. If you are taking these drugs, your doctor will check your kidney function frequently.
Another drug called Xgeva (chemical name: denosumab) works by limiting the activity of bone cells called osteoclasts, which in part cause the bone weakening and damage that can happen when breast cancer spreads to the bone. Xgeva is used to reduce bone complications and pain when breast cancer has spread to the bone. Bone damage can increase blood calcium; Xgeva helps to keep blood calcium levels normal.
An oral bisphosphonate called Bonefos (chemical name: clodronate) has shown to be effective as well. Bonefos is available in Europe.
Radiation therapy for bone metastasis
Radiation therapy can lower the risk of broken bones in areas that may be weakened from cancer. Radiation therapy is the most commonly used treatment for bone metastasis.
Radiation directed at the cancer will destroy the cancer cells so the bone can heal (bone cannot rebuild and strengthen itself if cancer cells are in the way). Additionally, if a bone in the arm or leg is seriously weakened, a surgeon may place a metal rod in the weak area to strengthen the bone.
Radiation therapy for scattered bone tumors
Some women develop scattered, painful bone tumors that don't respond to chemotherapy. These tumors can't be easily treated with localized radiation because the area needing treatment is too big. Another type of radiation can be given to reduce the multiple sites of pain. The radioactive chemical strontium-89 can be given intravenously (injected into one of your veins) as a one-time dose. The bone-making cells and the cancer cells in the bone take up the radiation given off by these chemicals. The treatment generally reduces pain, but just like chemotherapy, it can make you more prone to infection, anemia, and bleeding problems.
Radiation therapy for spinal cord compression
Spinal cord compression means the cancer is putting pressure on, or squeezing, your spinal cord — the large bundle of nerves in the middle of your backbone that connects the brain to the body. Cancer growing in the backbone can put pressure on the spinal cord that damages the nerves, resulting in back pain, weakness, and even paralysis, as well as altered bowel and bladder habits. Rarely, cancer damages the nerves by growing right around the spinal cord (and not in the backbone).
Treatment should start quickly to avoid permanent damage to your nerves. To shrink swelling around the problem, first you will be given a steroid in either pill form or sometimes as an injection. One of the most commonly used steroids is Decadron (chemical name: dexamethasone). Then radiation therapy is delivered to kill the cancer cells in the problem spot. Occasionally, you may need surgery to reduce pressure around the spinal cord.
Treatment for hypercalcemia
Hypercalcemia is a condition in which you have too much calcium in your blood. The tumor itself can cause it, or the tumor's effect on the bone can cause it.
Hypercalcemia can also be a side effect of cancer treatment. Too much blood calcium can cause serious medical problems. It has to be treated immediately with:
- extra fluids
- other medications, depending on the cause and degree of the high calcium level
- Aredia, Zometa, or Xgeva, which stop calcium from coming out of the bone and getting into the bloodstream