Bone cancer is a type of cancer that originates in the bones of the body. It can start in any bone but is most commonly found in the long bones of the arms and legs, as well as in the pelvis and spine. There are several types of bone cancer, but the most common type is osteosarcoma, which typically affects children and young adults.
Bone cancer occurs when cells in the bone begin to grow uncontrollably, forming a mass of abnormal tissue called a tumor. The tumor can cause pain, swelling, and stiffness in the affected bone, and can weaken the bone, making it more prone to fractures. Bone cancer can also spread (metastasize) to other parts of the body, such as the lungs, liver, and other bones.
Types of Bone Cancer
There are several types of bone cancer, which can be classified based on the type of cells from which cancer originates. The most common types of bone cancer included are –
- Osteosarcoma – It arises from the cells that form new bone tissue. These typically affect children and young adults.
- Chondrosarcoma – This type of bone cancer arises from the cells that form cartilage, which is the connective tissue that cushions the joints. It is more common in older adults.
- Ewing sarcoma – This is a rare type of bone cancer that typically affects children and young adults. It arises from the cells in the bone marrow that form blood cells.
4. Giant cell tumor of bone – This is a benign (non-cancerous) tumor that typically affects the ends of the long bones in the arms and legs. However, in rare cases, it can become malignant (cancerous).
5. Chordoma – This is a rare type of bone cancer that arises from the cells that form the notochord, which is a structure that develops in the early embryo and later disappears in most people.
6. Multiple myeloma – This is a type of cancer that affects the plasma cells in the bone marrow, which are responsible for producing antibodies to fight infections.
Each type of bone cancer may require different treatment approaches, so it is important to determine the specific type of bone cancer before starting treatment.
Causes and Risk Factors
Experts have not yet understood the causes of bone cancer, but certain factors may increase a person’s risk of developing the disease. These include –
- Inherited genetic mutations – Certain inherited genetic mutations, such as those that cause Li-Fraumeni syndrome or hereditary retinoblastoma, can increase the risk of bone cancer.
- Radiation exposure – Exposure to high doses of radiation, such as during radiation therapy for other cancers, may increase the risk of bone cancer.
- Paget’s disease – This is a bone disorder that causes abnormal bone growth and may increase the risk of bone cancer.
- Previous bone diseases – Previous bone diseases, such as osteosarcoma or chondrosarcoma, may increase the risk of developing a second bone cancer.
- Age – Bone cancer is more common in children and young adults, but it can occur at any age.
- Gender – Some types of bone cancer, such as osteosarcoma and chondrosarcoma, are more common in males.
- Race – Certain types of bone cancer, such as Ewing sarcoma, are more common in Caucasians.
The symptoms of bone cancer can vary depending on the type and stage of cancer, but some common signs and symptoms include –
- Pain – Pain in the affected bone is the most common symptom of bone cancer. The pain may be constant or may come and go, and may be worse at night.
- Swelling and tenderness – The affected area may be swollen and tender to the touch.
- Weakness and fatigue – As cancer progresses, it can weaken the affected bone, causing fatigue and weakness in the affected limb.
- Difficulty moving – Cancer may make it difficult to move the affected limb, and may cause stiffness or immobility.
- Unintended weight loss – Weight loss may occur as cancer progresses.
- Fractures – The affected bone may be more prone to fractures, and a fracture may be the first sign of bone cancer.
Diagnosis and Tests
If bone cancer is suspected, several diagnostic tests may be performed to confirm the diagnosis and determine the extent of cancer. Some common tests include –
- X-rays – X-rays can help identify abnormalities in the bone, such as tumors or fractures.
- MRI – MRI uses magnetic fields and radio waves to create detailed images of the bone and surrounding tissue, which can help detect bone tumors.
- CT scan – CT scan uses X-rays to create detailed images of the body, which can help identify the location and size of bone tumors.
- Bone scan – A bone scan involves injecting a small amount of radioactive material into a vein, which then accumulates in areas of the bone that have been damaged or are growing rapidly. The affected areas can then be identified with a special camera.
- Biopsy – A biopsy involves taking a small sample of the affected bone tissue and examining it under a microscope to determine if it is cancerous.
Once a diagnosis of bone cancer is confirmed, additional tests may be performed to determine the extent of the cancer, such as a PET scan, which can help detect if cancer has spread to other parts of the body.
Bone cancer is staged based on the size of the tumor, its location, and whether it has spread to other parts of the body. The staging system most commonly used for bone cancer is the TNM system, which stands for –
T (Tumor): This refers to the size of the primary tumor and whether it has grown into nearby tissues.
N (Node): This refers to whether cancer has spread to nearby lymph nodes.
M (Metastasis): This refers to whether cancer has spread to other parts of the body, such as the lungs or liver.
Using this system, bone cancer is typically divided into four stages –
- Stage I: The tumor is small and confined to the bone, and has not spread to nearby lymph nodes or other parts of the body.
- Stage II: The tumor is larger or has grown into nearby tissues, but has not spread to nearby lymph nodes or other parts of the body.
- Stage III: The tumor has spread to nearby lymph nodes, but has not yet spread to other parts of the body.
- Stage IV: The tumor has spread to other parts of the body, such as the lungs or liver.
The stage of bone cancer helps doctors determine the best course of treatment and the expected outcome (prognosis) for the patient.
The treatment for bone cancer depends on the type, location, stage, and size of the tumor, as well as the patient’s overall health. Some common treatments for bone cancer include –
- Surgery – Surgery is often the first treatment for bone cancer. The goal of surgery is to remove the tumor and some surrounding healthy tissue to ensure that all cancer cells are removed. Depending on the size and location of the tumor, limb-sparing surgery or amputation may be necessary to treat cancer. An artificial(limb) can be used after surgery for support.
- Radiation therapy – Radiation therapy uses high-energy radiation to kill cancer cells. It may be used before or after surgery, or as the primary treatment for bone cancer that cannot be surgically removed.
- Chemotherapy – Chemotherapy uses powerful drugs to kill cancer cells throughout the body. It may be used before or after surgery, or as the primary treatment for bone cancer that has spread to other parts of the body.
- Targeted therapy – Targeted therapy uses drugs that target specific proteins or other molecules that help cancer cells grow and divide. It may be used in combination with other treatments for bone cancer.
The choice of treatment depends on several factors, including the type and stage of the cancer, the patient’s age and overall health, and the potential risks and benefits of each treatment.
The outlook for bone cancer varies depending on several factors, including the type, location, stage, and size of the tumor, as well as the patient’s age and overall health. In general, the earlier a cancer is detected and treated, the better the outlook.
The five-year survival rate for primary bone cancer is about 70%, meaning that about 70% of people with primary bone cancer survive for at least five years after diagnosis. However, the survival rate varies depending on the specific type and stage of the cancer.
In addition to medical treatment, supportive care such as pain management, physical therapy, and emotional support can also play an important role in improving the outlook and quality of life for people with bone cancer.