The human body skeleton is one of the areas where cancer often spreads. Existing cancer cells (primary tumor) migrate through the circulatory system (blood) or lymph system to other parts of the body. These cancer cells can get stuck in different places and form new tumors called secondary tumors. The term implies the existence of multiple metastatic tumors.
Breast cancer, prostate cancer, lung cancer are types of cancer that commonly cause bone metastasis. Other cancer types like thyroid cancer and kidney cancer can also spread to the bones and metastasize. Metastatic cancer borrows the name of the location where it first developed before it spread. For example, breast cancer that metastasize in bones, still bears the name of breast cancer. Cancer that is formed in bone cells is considered bone cancer (primary tumor). Metastatic bone cancer is more common than bone cancer itself.
Bone Metastasis Causes
There are many reasons why cancer spreads to the bone tissue. Some cancer cells contain proteins that allow adherence to certain parts of the body, including bones. Another reason is that bones have certain characteristics that stimulate the development of certain cancers. As tumors get larger near lymph nodes, the chances of developing bone metastasis are higher. Bone metastases, most often are found in the spine, skull, ribs, upper limbs, femur bone, pelvic bones, and hip bone.
Bone Metastasis Symptoms
Cancer cells make bones more fragile and weakens them, in advanced forms of cancer, bones will start dissolving. There are several symptoms that can annouce bone metastasis but most often, patients do not experience any symptoms and bone metastasis are diagnosed after a routine x-ray.
- Pain – the most common symptom of bone metastases is intermittent pain, during slight movement. As metastases increase in size the pain is constant and gets worse when a person carries out certain activities;
- Fractures- cancer can cause bone fractures and this can happen even during the normal course of daily tasks, not only as a result of an accident. Bone metastasis is often first discovered when a cancer patient sufferes a fracture and is subject to medical investigation
- Numbness – tumors located in certain areas of the spine can cause compresion of nervous structures. The first sign of this phenomenon could be back pain, state of numbness and general weakness
- Difficulty urinating – among the symptoms of spinal metastases difficulties urinating or fecal incontinence can be present. These bone metastasis symptoms, present in a person with cancer are considered medical emergencies
- Paralysis – pressure on the spine can also cause paralysis. Different body parts can be affected, depending on the spinal area affected by tumor compression. Usually paralysis affects the legs.
- Hypercalcemia – bone metastasis can determine the transfer of calcium into the bloodstream. The high level of calcium in the bloodstream is called hypercalcemia, which can cause a variety of problems including constipation and dehydration. Weakness, decreased energy and confusion can be symptoms of these conditions. In severe cases, hypercalcemia can lead to coma even death.
Bone Metastasis Diagnosis
In most cases, bone metastasis is discovered before or at the same time as the primary cancer. When bone metastases are found before any other type of cancer, your doctor will try to determine the primary tumor, considering the type of cancer cells that lead to metastasis. Depending on the suspected cause of bone metastases, the specialist will require further investigations.
- X-ray radiography, CT scans and other imaging techniques provide detailed images inside the body and can confirm the presence of bone cancer. They will also reveal the severity of metastasis. These investigations can prevent any fractures that may occur due to bone metastasis.
- Blood and urine tests – Blood and urine tests can detect some specific evidence of bone metastases, such as high blood calcium level. Certain specific bone metastasis proteins can be dosed.
- Biopsy. The process involves taking a sample of tissue with a long needle and analyzing it under a microscope. In some cases surgery to perform the biopsy may be needed.
Bone Metastasis Treatment And Side Effects
Researchers constantly present new ways to treat bone metastases. These range from early detection techniques that could detect bone metastases before they cause severe damage to various ways to fight cancer, slowing its development or even preventing it. Current methods for treating bone metastases and its symptoms include:
- Chemotherapy – a common treatment used for advanced metastatic cancer. Drugs used in chemotherapy are usually injected or given orally and act throughout the entire body. The drawback is that chemotherapy affected healthy cells along with cancerous ones and there are a number of unpleasant side effects such as hair loss, nausea and vomiting. Chemotherapy can affect the bone marrow leading to clotting disorders, bleeding, increased risk of infection and fatigue
- Hormone therapy – hormones such as estrogen, and androgen hormones can encourage the growth of cancer cell types. To limit the effects of hormones on cancer cells, doctors can remove ovaries or testes (organs that produce these hormones). Administration of drugs that stop the production of hormones or are designed to block their effect on cancer cells are also useful. Hormone therapy has side effects similar to those seen during menopause and other hormonal fluctuations: hot flashes, anemia.
- Radiation therapy – bone metastases can be treated using radiation therapy . This treatment can use high or low doses of radiation depending on tumor size. Treatment is not painful, but can not be established if the bones are already severely damaged and weakened.