Bone cancer can either be primary or secondary. Primary bone cancer occurs where the bone cells begin to mutate and do not die as they should. Rather it forms a tumor as a result of uncontrolled cellular growth . This is distinct from secondary bone cancer which occurs as a result of metastasis. Hence, it is primary bone cancer where it starts in the bone and secondary bone cancer where the tumor originates outside the bone and spreads to the bone. In terms or comparative prevalence, secondary bone cancer is more common than primary bone cancer. The treatment of bone cancer depends on where the cancer started.
Causes of Primary Bone Cancer
As bone cancer is prevalent amongst young people and teenagers, it is opined that there may be an interrelation between the rise of cancerous bone tumors the changes that occur during the growth of the bone. However other factor that may contribute to primary bone cancer are as follows:
- Previous radiotherapy: Persons who previously underwent high doses of radiotherapy that includes the bones generally have a slightly greater risk of developing cancer in one of the bones.
- Non-cancerous bone conditions: Some non-cancerous bone conditions may actually serve to raise the likelihood of developing certain types of bone cancer. This can increase risk of developing osteosarcoma. An example of this is Paget’s disease of the bone. This disease is a non-cancerous condition that triggers enlarged or deformed bones in mostly people over the age of sixty. Again chondroma or osteochondroma, which is a non-cancerous bone tumor, can also develop into chondrosarcoma. Also are persons having Hereditary Multiple Exotoses (HME). This is a rare condition that causes growth of bony lumps especially in the arm or leg bones. Although HME may be hereditary, this is not always so.
- Faulty gene: Although an inherited faulty gene does not trigger the majority of bone cancers, persons with some genetic conditions are more likely to develop bone cancer. Such inherited faulty gene conditions are:
- Li-Fraument syndrome- people who inherit this condition have a raised likelihood of osteosarcoma.
- Retinoblastoma – children with retinoblastoma are also likely to develop osteosarcoma. Retinoblastoma is an extremely rare type of eye cancer triggered by an inherited faulty gene.
- Injuries: There is no evidence to support an often held opinion that injuries may be a cause of cancer. However, the injury may serve as a means of alerting the person of the existence of a bone cancer.
Types of Bone Cancer
There are diverse variations of bone cancer such as spindle cell sarcoma and angiosarcoma. Spindle cell sarcoma is similar to osteosarcoma but it is more likely to affect people above the age of 40 and also has various subtypes such as malignant fibrous histiocytoma, fibrosarcoma, leiomyosarcoma, and undifferentiated sarcoma of the bone. Angiosarcoma is extremely rare and can occur to any person at any age. It can occur at any part of the bone and in multiple places at the same time.
However there are four main types of primary bone cancer, which are osteosarcoma, Ewing’s bone sarcomas, chordoma, and chondrosarcoma .
Going by the alternate name of osteogenic cancer, osteosarcoma is the most common type of primary bone cancer today. Although it affects people of all ages, it is more common in young adults, adults in their sixties and teenagers. This is because osteosarcoma usually develops in growing bones. The most common location for osteosarcoma is around the knee, in the femur, upper arm or humerus and shinbone or tibia. Although there are many variations of osteosarcoma, the most common type is chondroblastic osteosarcoma. Others include periosteal and parosteal sarcoma, telangietatic sarcoma and small cell sarcoma. These types of osteosarcoma are extremely rare.
Causes of Osteosarcoma
Exact causes of osteosarcoma are unknown. A possible connection between the cancer and periods of rapid bone growth has been drawn. Again adults with a bone condition like Paget’s disease or who have had prior exposure to radiotherapy are more likely to develop bone cancer. Rarely, does it occur in people whose families inherited a faulty gene capable of raising the risk of developing cancer.
Symptoms of Osteosarcoma
The most common symptom of bone cancer is pain. This persistent bone pain usually occurs at night. Despite this, the symptoms may be varied due to the location of the cancer and its size in the body. where it is located close to joints, there is a likelihood of it causing tenderness or swelling in the area affected. Another way by which a primary bone cancer may be discovered is where a bone weakened by cancer breaks as a result of a normally insignificant accident or fall.
There are various methods by which osteosarcoma may be diagnosed. These methods include bone x-ray, biopsy, bone scan, medical resonance imaging or MRI scan, positron emission tomography scan and computer tomography scan.
Treatment of Osteosarcoma
The various ways of treating osteosarcoma are dependent on the size and position of the cancer, its grade, how far it has spread and the general health of the person involved. Osteosarcoma is usually treated with a combination of treatments. These include surgery, radiotherapy and chemotherapy.
- Surgery: This involves the removal of the affected part of the bone and some healthy tissue around it. The removed part is then replaced with either prosthesis or a bone graft. In other instances, amputation may be the only way to treat the cancer. This is usually so where it has spread from the bone to the nerves and blood vessels around it.
- Chemotherapy: This involves using anti-cancer drugs to kill the cancerous cells. This is especially useful in osteosarcoma as it shrinks the tumors prior to surgery in order to avoid amputation. Chemotherapy may still be administered after surgery to destroy any remaining cancer cells and stop them from expanding out of the bone. This process is called adjuvant chemotherapy. Persons under 30 years may also be given a drug called mifamurtide to help reduce the likelihood of a relapsed osteosarcoma.
- Radiotherapy: This is the use of high energy rays to kill cancerous cells whilst limiting the harm to normal cells. It is also used after a surgery. In such a circumstance, it is known as adjuvant radiotherapy. Radiotherapy is also utilized in treating primary tumor, where surgery is not possible.
2. Ewing’s Sarcoma
Ewing’s sarcoma is a primary bone cancer that can develop in any bone. However, the common bones affected by this type of bone sarcoma are the pelvis, femur, and tibia. This type of sarcoma is more common in males than females. Although uncommon, this type of bone sarcoma is also known to start in the soft tissues. There are several types of Ewing sarcoma, including Ewing sarcoma of bone, extraosseous Ewing sarcoma, peripheral primitive neuroectodermal tumor (pPNET), and Askin tumor . In such circumstances, it is referred to as extreaosseous Ewing’s sarcoma. Ewing’s bone sarcomas are all considered to be high grade sarcomas.
Causes of Ewing’s Sarcoma
Research is still ongoing to determine the cause of Ewing’s sarcoma. However, it is presumed that rapid bone growth may be a contributory factor, the reason why this cancer is more prevalent amongst young adults and teenagers.
Symptoms of Ewing’s Sarcoma
Like most bone sarcomas, the most common symptom is pain. However, this is dependent on the position of the cancer in the body. Swelling may also occur in the affected area making it become tender to touch.
Ways of Diagnosing Ewing’s Sarcoma
Like all bone sarcomas Ewing’s sarcoma can be diagnosed by a biopsy, medical resonance imaging, computer tomography, position emission tomography scan and bone marrow sample.
Treatment of Ewing’s Sarcoma
Treatment of Ewing’s Sarcoma may vary, depending on the size and position of the tumor. Generally combinations of various treatments are used to cure Ewing’s bone sarcoma. Usually treatment is first commenced to shrink the primary tumor and kill cancerous cells that have expanded to other parts of the body before treating it with surgery or radiotherapy 3-6 months later. However, treatment may be accompanied by side effects such as changes in the manner in which the heart and kidneys function. Also the treatment may increase the likelihood of a relapsed cancer in years to come.
This type of cancer is extremely rare and grows slowly. It commences in the bones of the spine, at the bottom of the spine or the neck. Although chordoma can occur at any age, it is more prevalent amongst persons of 40 years and 50 years. Chordoma does not often spread to other parts of the body. However, where it does it may reach places such as the skin, nearby lymph nodes, lungs, bone and liver. Chordoma is more common in men than women.
Causes of Chordoma
Research is still ongoing to determine the cause of chordoma as the cause of this category of bone cancer is still unknown.
Symptoms of Chordoma
As chordoma develops slowly, it takes a while for the symptoms to show. The sign that may show depends on the location of the tumor. Where the chordoma starts in the spine symptoms are pain, numbness, erectile dysfunction, poor bladder control and difficulty in mobility. Where the chordoma starts in the skull, the symptoms are dizziness, facial pain, headache, double vision and increased inconvenience in swallowing.
Diagnosis of Chordoma
Chordoma can be diagnosed by a computer tomography scan, medical resonance imaging scan and a biopsy.
Treatment of Chordoma
Treatment of chordoma is dependent on the position and size of tumor as well as your general health. The various ways of treating chordoma are surgery, radiotherapy and chemotherapy. Surgery is the favored treatment used to remove the tumor and nearby tissues containing the cancerous cells . In certain situations, a surgery to remove chordoma of the spine may alter the manner in which the blade and bowel functions. A colostomy or urostomy may also be required. Radiotherapy may also be used alone to treat chordoma or alongside chemotherapy where surgery is impossible. It is also used after surgery to kill any remaining cancerous cells and on occasions in which there is a relapse and surgery is impossible.
Radiotherapy may also be used as a relief to certain symptoms of chordoma such as pain. Some more recent types of radiotherapy used in the treatment of chordoma are image guiding radiotherapy, stereotactic radiotherapy and intensity modulated radiotherapy. Chemotherapy utilizes cytoxic drugs to destroy cancerous cells. However, the effectiveness of chemotherapy in the treatment of chordoma is limited.
Chondrosarcoma, otherwise known as cancer of the cartilage, occurs mostly in people over the age of 40 years and is slightly more common in men. Usually this cancer grows slowly and affected sites are usually the pelvis, femur, humerus, scapula and ribs.
Causes of chondrosarcoma
The causes of chondrosarcoma are largely unknown. However, chondrosarcoma is more frequent when people have had osteochondra. Other factors likely to increase the risk of chondrosarcoma are:
- Ollier’s disease
- Hereditary multiple exostoses (HME)
- Maffuci syndrome
Symptoms of Chondrosarcoma
The most common symptom of chondrosarcoma is pain. The symptoms are dependent on the position of the cancer in the body and size.
Diagnosis of Chondrosarcoma
Chondrosarcoma can be diagnosed by biopsy, which could either be a needle biopsy or a surgical biopsy. Other methods of diagnosing chondrosarcoma are bone scan, medical resonance imaging, computer tomography and position emission tomography.
Treatment of Chondrosarcoma
Chondrosarcoma is commonly treated by surgery and chemotherapy. Although radiotherapy is rarely utilized in treating chondrosarcoma, it may come in handy in some instances.
Grading of Bone Sarcomas
Grading is the name given to the process of observing how the cancer cells appear under a microscope to determine how rapidly a cancer may grow and develop. Bone sarcomas are described as low-grade bone sarcomas where the cancerous cells and the normal cells appear very much alike. Such cells are slow to grow and not as likely to spread high-grade sarcomas. In high-grade sarcomas, cells appear abnormal and as such have a greater likelihood of rapid growth and expansion. Osteosarcomas are generally high-grade. The only exception is parosteal osteosarcoma, which is generally low grade.
Staging Bone Sarcomas
Staging is a describer of the size of the tumor as well as whether it has spread from its original position and how far if so. Staging is the methodology used in determining the most appropriate treatment for bone sarcomas.
- Stage 1A – At this stage the cancer is of a low grade measuring less than 8 centimeters in diameter.
- Stage 1B – Bone sarcomas are categorized as stage 1B where it is a low grade sarcoma with a measurement greater than 8 centimeters in diameter
- Stage 2A – High-grade sarcomas that are less than 8 centimeters in diameter are placed within this category.
- Stage 2B – Bone sarcomas which high grade and more than 8 centimeters in diameter are placed within this category. Most osteosarcomas are within this grouping.
- Stage 3 – At this stage the sarcoma is a high grade and is situate in more than one place in the bone.
- Stage 4A – A stage 4A bone sarcoma is cancer of any grade that has spread to the lung
- Stage 4B – This is sarcoma of any grade that has spread to the lymph nodes or other parts of the body other than lungs.
 Lasley, I. (2010). 21st Century Cancer Treatment (pp. 62, 63, 64). CreateSpace Independent Publishing Platform. https://books.google.com.ng/books?hl=en&lr=&id=er614PVQPVkC&oi=fnd&pg=PA3&dq=%22what+is+bone+cancer%22&ots=F81HQCGqyC&sig=T8i_d0Nq61pZ-9OJ4P7xfcx00Bg&redir_esc=y#v=onepage&q=%22what%20is%20bone%20cancer%22&f=false Date accessed 19 April 2015
 Chordoma-uk.org,. (2015). Diagnosis and treatment for Chordoma bone cancer. Retrieved 20 April 2015, from http://chordoma-uk.org/diagnosis-and-treatment
 Macmillan.org.uk,. (2015). Chordoma – Cancer Information – Macmillan Cancer Support. Retrieved 20 April 2015, from http://www.macmillan.org.uk/Cancerinformation/Cancertypes/Bone/Typesofbonecancer/Chordoma.aspx