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Cancer of the Bone – What must I do?

   Cancer in Bones 

Cancer of the bone is a general term used when cancer cells are seen in the bone. The cancer cells may be of several different types. Bone cancer begins when cells in the bone begin to change, grow without control, and no longer die, forming a mass called a tumor. Primary bone cancer is rare and accounts for less than 1% of all new cancers.  Osteosarcoma and chondrosarcoma each make up 35% of primary bone cancers, followed by Ewing’s family of tumors (10%), chordoma (5%), and malignant fibrous histocytoma (MFH)/fibrosarcoma (2%). The remaining cases represent other, rare types of bone cancer. Leukemias are cancers involving the marrow and affect production of blood cells. Lymphoma  is a term that refers to many, very different types of cancer of the lymph system. The lymph system carries lymph, a colorless fluid containing lymphocytes (white blood cells). These malignant lymph cells can spread to any organ in the body including the bone marrow. Multiple myeloma is a cancer of the plasma cells in the bone marrow, the spongy tissue inside of bones. Plasma cells are a part of the body’s immune system and produce antibodies that help the body fight infection. Myeloma often causes structural bone damage resulting in painful fractures. Therefore, primary bone cancer is a completely different type of cancer with very different treatments.

It is much more common for bones to be the site of metastasis (spreading) from other cancers, such as breast, lung, nasopharynx, thyroid, kidney, stomach or prostate cancer. Secondary bone cancer does not start in the bone, but is the result of cancer cells spreading to the bone from a primary tumour as described above. Sometimes only one area of bone is affected, but in some people a number of bone secondaries develop, often in different bones in the body. Not all the secondaries will cause symptoms or problems. Although a secondary bone cancer can occur in any bone in the body, the most commonly affected bones are those of the spine, ribs, pelvis, skull, and the upper bones of the arms (humerus) and the legs (femur).

    Symptoms of Secondary Bone Cancer

(i)      Bone pain

The most common symptom of secondary bone cancer is pain in the affected area. The pain may be a dull, persistent ache that often gets worse at night when the muscles are relaxed. There may also be swelling and tenderness in the area. If you experience this type of pain and it lasts for more than one to two weeks, it’s best to let your doctor know as soon as possible. Although bone secondaries can occur in several different bones at the same time, usually only one or two areas are painful.

(ii)     Weakened bones

Sometimes if a bone is weakened by cancer it will break (fracture), even if you have not had an accident or fall. This is known as a pathological fracture.

(iii)    Raised calcium level

When bones are affected by secondary cancer cells, increased amounts of calcium (the substance that helps to build bones) may be released into the blood. A raised level of calcium in the blood is called hypercalcaemia. It can cause symptoms such as tiredness, feeling sick (nausea), constipation, thirst and confusion. However, in many people hypercalcaemia is discovered with a blood test, before any symptoms develop.

(iv)    Pressure on the spinal cord

If secondary bone cancer affects the bones of the spine it can put pressure on the nerves in the spinal cord. This is called spinal cord compression and may cause symptoms such as pain, muscle weakness and sometimes tingling and numbness of the limbs. If the lower spine is affected, it may also affect how the bowel and bladder work. If you have weakness, pain, tingling or numbness in the legs it is very important to let your doctor know as soon as possible so that treatment can be given to prevent permanent damage.

(v)      Other symptoms

Sometimes secondary cancer in the bone can make you feel more tired than usual. Occasionally secondary cancer in the bone can affect the way that the bone marrow works. If the bone marrow is unable to produce enough blood cells you may become anaemic, and be more likely to get infections or to have bruising or bleeding.

    How Secondary Bone Cancer is Diagnosed   

Your doctor is likely to arrange a number of tests for you if they think it’s possible that your cancer has spread to the bones. You may worry that the cancer has come back or spread, but without the results of the tests you cannot know for sure. In this situation you may find yourself torn between believing there is some other cause for your symptoms and thinking the worst. The tests that can show that that you have secondary bone cancer include:

(a) blood test that may be done to check your general health and the level of calcium in your blood. Serum alkaline phosphatase is an enzyme made in the liver, bone and placenta. Abnormally high blood levels of alkaline phosphatase may indicate disease in bone or liver or bile duct obstruction.

(b) bone x-ray that can show up certain changes in the bone and may show that a secondary bone cancer is present. A cancer of the bone may not always show up on a plain bone x ray

(c) bone scan is a more sensitive test than a simple x ray and shows up any abnormal areas of bone more clearly. A small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Abnormal bone absorbs more radioactivity than normal bone, so these areas are highlighted and picked up by the scanner as hot spots. The level of radioactivity used in the scan is very small and does not cause any harm to your body

(d) CT (computerised tomography) scan takes a series of x-rays, which build up a three-dimensional (3D) picture of the inside of the body

(e) MRI (magnetic resonance imaging) scan is similar to a CT scan, but uses magnetic fields instead of x-rays to build up a series of cross-sectional pictures of the body

(f) PET (positron emission tomography) – CT scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body together with CT scan. Before the scan, a very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Areas of cancer are usually more active than surrounding tissue and show up on the scan.

(g) Biopsy – is the removal of a small amount of tissue for examination under microscope. Only a biopsy can make a definite diagnosis of cancer in the bone. The sample removed from the biopsy is analyzed by a pathologist (doctor who specializing interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). The type of biopsy (needle or open incisional) perform will depend on the location of the cancer. However, there are some cases where a biopsy may not be able to perform.

 If a Secondary Bone Cancer is Found Before the Primary Cancer, y0ur doctor may arrange for you to have tests to find where the primary cancer is in your body. Such tests may include mammogram to look for primary cancer in the breast, a chest x-ray and CT scan to check for lung cancer, a CT or ultrasound scan of abdomen and pelvis to look for kidney cancer or a prostate ultrasound and blood sample to check for prostate cancer.

  Treatment of Secondary Bone Cancer

A number of different types of treatment can be used to treat people with secondary bone cancer. The treatment you have will depend on which bone is affected, where the cancer first started (the primary cancer), how damaged and weakened the bone is and how the cancer is affecting you – the symptoms you have, size of the tumour and your overall health.

It is often a team of doctors will work with you to determine the best treatment plan. The aim of treatment for a secondary bone cancer is to: (i) relieve any symptoms and make you more comfortable (ii) reduce the number of cancer cells (iii) lower the risk of developing a bone fracture (iv) reduce the risk of developing a high calcium level in the blood

(i)       Relieving symptoms

Apart from using painkillers and other pain relieving drugs, the main method of relieving symptom is radiotherapy. Radiotherapy may be given by machine such as external beam radiotherapy or radioisotopes.

In the bone, osteoclasts destroy the old bone and osteoblasts deposit new minerals and build new bone. Cancer cells which have spread to the bone produce chemicals that change the activity of these cells, upsetting the normal balance. The osteoclasts (the cells that destroy old bone) become overactive and this commonly causes small holes in the bone. Bisphosphonates are drugs that restrict the action of the osteoclasts. Examples of bisphosphonates include zoledronic acid (Zometa®), pamidronate (Aredia®), ibandronate (Bandronat®) and clodronate (Bonefos®). They are bone strengthening drugs used to reduce the risk of fracture or hypercalcaemia and to relieve pain. Bisphosphonates may be given into a vein through a drip (intravenously) in the outpatient department, every 3–4 weeks. Some bisphosphonates can be taken as tablets, which must be taken on an empty stomach at least half an hour before food. Many clinical trials have shown the benefits of bisphosphonates in patients with secondary bone cancer in reducing these skeletal complications and hypercalcemia.

Recently, a new drug denosumab (Prolia®), a fully humanized monoclonal antibody that blocks and inhibits activity of osteoclasts, decreasing bone resorption and increase bone density. This drug is showing promise in treatment of osteoporosis, bone metastasis, treatment induced bone loss and multiple myeloma.

  Types of Treatment for Secondary Bone Cancer

The type of treatment you have depends on where your cancer started. This is because the secondary cancer cells in the bone have come from where the primary cancer is and will usually respond to the same type of treatment as the primary cancer. To treat the cancer you may be offered:

  • Chemotherapy – use of drugs to kill the cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. Chemotherapy for bone cancer can usually be given as an outpatient treatment, which is treatment that can be given at a clinic or doctor’s office instead of being admitted to a hospital.
  • Hormone therapy for breast and prostate cancer since they the growth of these cancer cells can be controlled by using hormones
  • Combination of hormonal therapy and chemotherapy
  • Surgery may be offered if x-ray shows that a secondary cancer has weakened a long bone such as the thigh bone (femur) or upper arm bone (humerus). If there’s a risk of the bone breaking, you may need an operation to strengthen it and prevent a break from happening. A metal pin or a locking nail (a nail with screws at each end) can be put down the middle of the weakened bone. This secures and strengthens the bone, holding it firm so that it won’t break. The pin or nail can stay in permanently to continually protect the bone. Whether this operation is appropriate for you will depend on which bone is affected by your secondary cancer.
  • Vertebroplasty and kyphoplasty are procedures for patients with vertebral compression fractures. Vertebroplasty  is a procedure in which a needle is used to deliver a cement material into the collapsed vertebral body and thereby stabilize it. Ths procedure reduces vertebral body movement and the associated bone pain. Balloon kyphoplasty is a procedure that allowed placement of a needle in the collapsed vertebral body to place an inflated balloon which is then withdrawn to allow cement to be injected into the space. This ten stabilize the fracture and restore the height of the vertebra and reduce the bone pain

Regular communication with your doctor is important in making informed decisions about your health care. Consider asking the following questions of your doctor:

  What Questions to Ask Your Doctor?

  • What type of bone cancer do I have?
  • What stage is the bone cancer? What does that mean?
  • Where exactly is the cancer located?
  • Can you explain my pathology report (laboratory test results) to me?
  • What are my treatment options?
  • What clinical trials are open to me?
  • Which treatment option do you recommend? Why?
  • What are the possible side effects of this treatment, both in the short term and the long term?
  • What is the expected timeline for my treatment plan?
  • How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
  • What follow-up tests will I need, and how often will I need them?
  • What support services are available to me? To my family?