Bone cancer occurs when a tumour or abnormal mass of tissue develops in a bone. A tumour may be malignant, which means it grows and spreads to other parts of the body. A malignant tumour is referred to as cancerous. Cancer that develops in the bones is rare and it develops in the skeletal system and destroys the tissue.
The two main types of bone cancer are primary and secondary.
- Primary bone cancer occurs when cancer develops in the cells of the bone. This is the most serious of all bone cancers. They develop in the bones or the surrounding tissue, such as cartilage.
- Secondary bone cancer occurs when cancer develops elsewhere and spreads to the bones.
What are the symptoms of bone cancer?
There are certain symptoms you may experience which indicate that you may be suffering from bone cancer. Be vigilant of these signs happening to you and your loved ones:
- Bone pain.
- Unintended weight loss.
- A weakened or fractured bone.
- Tenderness and swelling near the affected area.
Do you think you have any of the above symptoms?
What are the causes?
The cause of most bone cancers is unknown, but doctors have found certain factors associated with an increased risk, which include the following:
- If you have a family history of cancer
- If you have received radiation treatment or therapy in the past
- If you have Paget’s disease, which is a condition that causes the bones to break down and then grow back abnormally
- If you have currently or previously had multiple tumours in the cartilage, which is the connective tissue in the bone
What are the types of malignant bone cancer?
Bone cancers are divided into separate types based on the type of cell where cancer began and the most common type of bone cancer include the following:
- Osteosarcoma: Osteosarcoma or osteogenic sarcoma is the most common primary bone cancer. It starts in the bone cells. This generally affects children and adolescents, but it can also occur in adults. These tumours develop at the tips of the long bones in the arms, legs, or pelvis. Osteosarcoma may also develop in the hips, shoulders, or other locations. It affects the hard tissue on the outer layer of your bones.
- Chondrosarcoma: It develops in cartilage cells and may develop in the pelvis, thigh areas, and shoulders of older adults. It develops in the subchondral tissue, which is the tough connective tissue between your bones.
- Ewing sarcoma: It is the third most common primary bone cancer, and the second most common in children, teens, and young adults. Ewing sarcoma is rare cancer that either develops in the soft tissues surrounding the bones or directly in the bones of children and young adults. The arms, legs and pelvis are commonly affected.
- Multiple myeloma (MM): It is a blood cancer that may lead to one or more bone tumours. It develops when cancer cells grow in the bone marrow and cause tumours in various bones. Multiple myeloma affects older adults.
- Fibrosarcoma and malignant fibrous histiocytoma: It develops in the soft tissue around the bones, such as tendons, ligaments, fat or muscle. These types of bone cancer are common in older adults and usually affect the arms, legs or jaw.
- Giant cell tumour of bone: The tumour in the bone has benign and malignant forms, although the malignant form is less common. It develops in the arm or leg bones of young and middle-aged adults and rarely spreads to other parts of the body. However, these cancers can recur after surgical removal, and the chances of spreading to other areas are also high.
- Chordoma: It affects the bones in the spine and the base of the skull. This type of bone cancer develops in adults 30 or older, particularly men. It tends to be a slow-growing tumour with a low risk of spreading to other areas, but it may return at the original site if not removed completely during surgery. Chordoma will eventually spread to the lungs, liver or lymph nodes.
- Metastatic bone cancer: It develops in the bone but spreads to other parts of the body. Bone cancer that spreads to other organs or tissues is still called bone cancer, even though it has spread to the lungs or lymph nodes.
Bone cancer stages are based on four categories:
- Stage I: The cancer cells are still localized to the bone, therefore the tumour is considered low-grade. This is divided into two subcategories:
- Stage IA: These tumours are less than 8 cm in size.
- Stage IB: The tumour is larger than 8 cm and can be found in several places in the same bone.
- Stage II: These cancers are localized to the bone, but they are considered high-grade. This is divided into two subcategories:
- Stage IIA: The tumour is less than 8 cm.
- Stage IIB: The tumour is larger than 8 cm.
- Stage III: At this stage, Primary bone cancers are still localized to the bone, but they are high-grade and have spread to various places within the same bone.
- Stage IV: Stage IV bone cancer is the most advanced form of bone cancer. In stage IV, cancer has spread beyond the bone to other parts of the body. Stage IV bone cancer can be any tumour or node, which means the tumour may be any size and may have grown into the lymph nodes.
This is divided into two subcategories:
- Stage IV A: Cancer has spread to the lungs.
- Stage IV B: Cancer has spread another organ besides the lung. Stage IV bone cancer and metastatic cancer are the same.
How much does it affect other parts of the body?
- At Stage 1 cancer has not spread to the other parts of the body.
- At Stage 2 cancer has not spread, but may become invasive, making it a threat to other tissue.
- At Stage 3 cancer has spread to one or more parts of the bone, and it is invasive.
- At Stage 4 cancer has spread to the other organs such as the lungs, brain and it has also spread to the tissues surrounding the bone.
The prognosis for bone cancer:
- The prognosis for survival for bone cancer patients depends upon the particular type of cancer and whether it has spread to other parts of the body.
- The overall 5-year survival rate for all bone cancers in adults and children is about 70%. The 5-year survival rate is the percentage of people with bone cancer who survive at least 5 years after diagnosis.
- Chondrosarcomas has an overall five-year survival rate of about 80%. But when chondrosarcomas have not spread, it has a 91% chance of surviving for 5-years after diagnosis.
- The 5-year survival rate for localized osteosarcomas is about 60%-80%. If cancer has spread beyond the bone, the survival rate is about 15%-30%.
- Ewing sarcomas have a five-year survival rate of about 70% when found in a localized stage. If they have spread outside the bone, the survival rate reduces to 15%-30%.