What are the other Names for this Condition? (Also known as/Synonyms)

• Central (Medullary) Osteogenic Sarcoma
• Conventional High Grade Osteosarcoma
• Conventional Osteogenic Sarcoma

What is Conventional Osteosarcoma? (Definition/Background Information)

• Osteosarcoma forms a class of highly-cancerous, high-mortality, bone tumor. After multiple myeloma, it is the second-most common primary tumor of the bones
• Conventional Osteosarcoma is the most common type of osteosarcoma. They involve the metaphysis region of the bones, with half of them occurring around the knees
• The distal femur is the most common site for this type of tumor. It is very rare for Conventional Osteosarcoma to be present in the ankles and the wrist joints
• The exact cause of the condition is unknown and presently, it is not possible to prevent Conventional Osteosarcoma occurrence
• A treatment of this bone tumor may involve surgery, chemotherapy, and radiation therapy. The prognosis of Conventional Osteosarcoma depends on the stage of cancer; higher grade osteosarcomas indicate a poorer prognosis

Osteosarcomas are classified in several different ways. They may be classified based on their cause/origin, location, or even based on certain diagnostic findings.

Based on where they occur, Osteosarcoma is classified as Medullary Osteosarcoma (occurring in the bone cavity) and Surface Osteosarcoma (occurring on the bone surface).

• Medullary Osteosarcomas are of several different types, and these include:
  • Conventional Osteosarcoma
  • Osteosarcoma of Jaw Bones
  • Post-Radiation Sarcoma
  • Osteosarcoma arising in Paget's Disease of Bone
  • Osteosarcoma in other Benign Conditions
  • Telangiectatic Osteosarcoma
  • Small Cell Osteosarcoma
  • Low-Grade Osteosarcoma
  • Multicentric Osteosarcoma
• Surface Osteosarcomas are of several different types, and these include:
  • Parosteal Osteosarcoma
  • Periosteal Osteosarcoma
  • High-Grade Surface Osteosarcoma

Who gets Conventional Osteosarcoma? (Age and Sex Distribution)

• Conventional Osteosarcoma has a bimodal (with two modes) age distribution, having the first peak during adolescence and the second peak in older adulthood
• The first peak is in the 2nd decade of life (between 10-19 years) and the condition affects children and young adults. The second peak occurs around the age of 60 years
• Some studies have shown that males with these bone tumors have a much worse prognosis than women; though, this is not well-established
• There is no known ethnic/racial preference; the condition is known to occur worldwide

What are the Risk Factors for Conventional Osteosarcoma? (Predisposing Factors)

The risk of osteosarcoma is linked to the following factors:

• Some genetic mutations are associated with osteosarcoma; including mutations in Rb gene and P53
• Individuals with bilateral retinoblastoma have a higher risk of developing the condition
• A few genetic disorders, such as Rothmund-Thompson syndrome, Bloom’s syndrome, Li-Fraumeni syndrome, hereditary multiple exostosis, and Werner syndrome, have been linked to the condition
• Paget’s disease of the bone, fibrous dysplasia, osteoblastoma, Ollier disease, and chemotherapy, are other conditions and disorders that are thought to be associated with osteosarcomas
• A previously performed radiotherapy for other cancer conditions - the tumor may be radiation-induced. The radiation has an expected side effect of damaging the genetic material in the normal cells. This can lead to the development of a “secondary” cancer
• Any physical injury or trauma

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Conventional Osteosarcoma? (Etiology)

• The exact cause and mechanism of Conventional Osteosarcoma formation, is unknown
• The tumor can occur de novo or spontaneously (termed as a primary osteosarcoma), or due to some preexisting conditions and abnormalities (termed as a secondary osteosarcoma)
• Such preexisting conditions could include radiation-exposure, genetic anomalies, the presence of multiple chondroma, and any well-established physical injury or trauma
• A radiation-influenced tumor takes many years to develop, after the radiation exposure has ceased. This radiation may have been previously administered for treating other cancers

What are the Signs and Symptoms of Conventional Osteosarcoma?

The presentations are based on the location of the tumor. Conventional Osteosarcoma signs and symptoms may include:

• In the initial growing phase of the tumors, they are normally asymptomatic. The soft tissue tumors grow at a moderate rate, and then they suddenly start to rapidly progress
• Due to large size of the tumor, the adjoining organs, nerves, and muscles may be compressed or restricted. Often, these signs along with pain, swelling, and tenderness, are the first indications of Conventional Osteosarcoma
• Symptoms can be present from few months to years
• Pathological fractures may occur at the tumor site (occasionally)
• In some individuals, organ dysfunction and internal hemorrhages may be observed. These may be sudden and spontaneous developments
• Lesions beneath the skin (in rare cases), may appear as painful inflammations
• Frequently, the long bones of the legs and arms are affected. The region of the thigh bone and shinbone around the knees is the most commonly affected area

How is Conventional Osteosarcoma Diagnosed?

A diagnosis of Conventional Osteosarcoma is made using the following tools:

• Physical examination, evaluation of patient’s medical history
• Histopathological studies conducted on a biopsy specimen - the specimen is examined under a microscope by a pathologist, to arrive at a definitive diagnosis
• X-ray studies of the tumor
• MRI scan or CT scan of the affected area

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Conventional Osteosarcoma?

Complications of Conventional Osteosarcoma are dependent on the site and severity of the tumor. These include:

• Damage of the following organs due to metastasis - liver, bones, and lungs
• Usually by the time osteosarcomas are detected, chances are that they would have proliferated and metastasized aggressively, damaging organs and tissues beyond repair
• They are known to have a high recurrence rate, even on surgical excision and removal
• Deep-seated tumors (those buried inside the body tissues) may cause damage to adjoining tissues and organs
• Blood loss during invasive treatment methods may be heavy
• Damage to vital nerves, blood vessels, and surrounding structures, during surgery
• Side effects from chemotherapy (such as toxicity), radiation therapy

How is Conventional Osteosarcoma Treated?

Treatment measures for Conventional Osteosarcoma include the following:

• Any combination of chemotherapy, radiation therapy, and invasive procedures, maybe used to treat the tumor
• Wide surgical excision of Conventional Osteosarcoma and removal of the entire lesion is the standard treatment mode. If the tumor is not fully removed, then it will recur
• Embolization of the tumor is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• When the tumor is at an inaccessible location, or is unsafe for surgical intervention, non-invasive procedures are adopted
• Post-operative care is important: A minimum activity level is to be ensured, until the surgical wound heals
• Follow-up care with regular screening and check-ups are important

How can Conventional Osteosarcoma be Prevented?

• Current medical research have not established a way of preventing Conventional Osteosarcoma occurrence
• However, the presence of any tumor or lesion should be immediately informed to the physician and periodic follow-up and screening maintained
• Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already endured the tumor. This is due to both its high metastasizing potential and chances of recurrence. Often several years of active vigilance is necessary

What is the Prognosis of Conventional Osteosarcoma? (Outcomes/Resolutions)

• The prognosis of Conventional Osteosarcoma is unknown

However, several prognostic markers are identified by research which helps determine the prognosis of Conventional Osteosarcoma. Many of these prognostic markers are based upon defective genes or defective proteins found in the tumor. Some of these genetic defects that alter the prognosis are explained below.

The following conditions result in or indicate a poor prognosis:

• 13q14 loss of heterozygosity (gene loss) and mutations in Rb gene
• Presence of MDR-1 gene mutation, which is a multi-drug resistant gene, results in tumor not responding to certain chemotherapy agents
• The presence of c-FAS mutations in patients result in poorer prognosis, due to a poor response of the condition to chemotherapy and a higher chances of recurrent and metastatic osteosarcoma
• HER-2 over expression in tumor
• Loss of M-TAP gene

Other factors that are related to osteosarcoma prognosis include:

• Loss of heterozygosity of 18q in patients with Paget’s disease of the bone, has been shown to increase the development of osteosarcoma, in such patients
• Studies have shown that such tumors in children have the worst prognosis, compared to young adults with the tumor
• Some studies seem to indicate that men with these bone tumors have poorer prognosis, than women; but, this has not been substantiated
• Location of the tumor also determines its outcome; tumor in distal parts of the knee and elbow, have better outcomes, than those at other locations
• The size of the tumor also determines its prognosis; normally, larger tumors have much poorer prognosis than smaller-sized tumors
• Duration of symptoms are important factors too:
  • A shorter duration of symptoms lead to a worse prognosis
  • A longer duration of symptoms lead to a better prognosis
• A presence of spontaneous necrosis leads to the worst prognosis. Spontaneous necrosis means a type of necrosis that is present due to tumor growth and not due to treatment with chemotherapy
• In general, patients with primary osteosarcoma have better prognosis than those with secondary osteosarcoma

Additional and Relevant Useful Information for Conventional Osteosarcoma:

• Best upon histology, there are different types of Conventional Osteosarcoma, as examined under a microscope. These include:
  • Giant cell rich osteosarcoma
  • Chondroblastic osteosarcoma
  • Pleomorphic osteosarcoma
  • Fibrosarcoma-like osteosarcoma
  • Osteoblastic osteosarcoma
• There are approximately 1000 cases of osteosarcomas, diagnosed each year in the United States