Osteosarcoma

What is Osteosarcoma?

Osteosarcoma is a primary malignant bone tumor that predominantly occurs in areas of active growth, such as the femur, tibia, and humerus. It develops from immature bone cells that begin to divide uncontrollably, destroying healthy tissue. Most often, the tumor is diagnosed in adolescents during periods of rapid growth, but the disease can also develop in adults, particularly after the age of 50.

Causes and Risk Factors

The exact causes of osteosarcoma remain unknown, but several factors have been identified that may contribute to its development:

Genetic Predisposition

Some genetic syndromes may increase the risk of developing osteosarcoma. The most well-known is Li-Fraumeni syndrome, associated with TP53 gene mutations, which raises the likelihood of various types of cancer. Other genetic disorders (such as Kaufman syndrome) can also be linked to a higher risk.

Previous Radiation Therapy

People who have undergone radiation therapy, especially in childhood or adolescence, have a higher risk of developing osteosarcoma in the irradiated area. Radiation damages cell DNA, which can lead to mutations and tumor growth.

Bone Diseases

Certain conditions (such as Paget's disease) that disrupt normal bone metabolism can increase the risk of developing tumors. In such cases, bones become more fragile and susceptible to tumor growth.

Injuries

Although injuries are not a direct cause of osteosarcoma, they can accelerate the manifestation of the disease. For example, bone damage can cause inflammation, which in turn may stimulate tumor growth if there is already a predisposition in the tissue.

In Russia, studies are actively being conducted on environmental factors such as air pollution or exposure to chemicals that may also contribute to the development of osteosarcoma.

Signs and Symptoms

Osteosarcoma may develop without noticeable signs in the early stages, and its symptoms are often mistaken for the effects of injuries or excessive physical activity. However, paying attention to pain and other symptoms can help in early detection.

Common Symptoms of Osteosarcoma:

• Bone pain – the most common symptom. In the early stages, the pain may be mild and occur only during physical activity, but over time it becomes constant, intensifies at night, and does not respond well to painkillers.

• Tumor or swelling at the affected site – appears as the tumor grows and may be accompanied by increased temperature, redness, and swelling of soft tissues.

• Limited mobility – when bones near joints are affected, the range of motion decreases, leading to stiffness and discomfort.

• Spontaneous fractures – in advanced cases, the tumor weakens the bone, leading to fractures even with minor loads.

• General symptoms – may include fatigue, low-grade fever (37-38°C), and weight loss.

Important: Any persistent bone pain in children and adolescents, especially if accompanied by swelling, requires mandatory medical evaluation. In Russia, late medical consultation is common, which lowers the chances of successful osteosarcoma treatment.

Diagnosis of Osteosarcoma

Accurate diagnosis of the tumor and determination of its stage involves a comprehensive set of methods. The main diagnostic steps include a medical examination, collection of patient history, and information about injuries or genetic diseases.

Diagnostic Methods:

• X-ray – to detect changes in bone tissue.

• MRI – to assess the involvement of soft tissues and joints.

• CT scan – to examine bone structures and detect metastases.

• Biopsy – to collect a tissue sample for confirmation of the diagnosis.

• PET-CT and scintigraphy – to detect metastases and tumor spread.

The diagnosis of osteosarcoma requires a multidisciplinary approach. Early detection significantly increases the chances of successful treatment.

Stages of Osteosarcoma

Staging helps doctors determine the extent of the tumor and choose the most effective treatment. Stages are based on tumor size, location, and the presence of metastases:

• Stage I – A localized, low-grade tumor.
  The tumor is confined to one bone and does not spread to surrounding tissues. This type of tumor is less aggressive, which increases the chances of successful treatment if addressed in time.

• Stage II – A localized, high-grade tumor.
  The tumor is located within a single bone but is highly aggressive and requires more intensive treatment.

• Stage III – Multiple lesions within the same bone.
  At this stage, the tumor forms several lesions within one bone, making treatment more complex.

• Stage IV – Presence of metastases, most often in the lungs.
  At this stage, the tumor extends beyond the bone and spreads to other organs. This is the most severe form of the disease.

Osteosarcoma Treatment Methods

Modern treatment of osteosarcoma includes several key components:

• Neoadjuvant chemotherapy – administered before surgery to shrink the tumor, making surgery easier and reducing the risk of metastasis.

• Surgical removal of the tumor – complete tumor excision. Ideally, limb-sparing surgery is performed, but in complex cases, amputation may be necessary.

• Adjuvant chemotherapy – administered after surgery to destroy any remaining microscopic cancer cells and prevent recurrence.

• Radiation therapy – used when the tumor cannot be completely removed or is located in difficult-to-reach areas. It may also be applied post-surgery to eliminate residual cancer cells.

Targeted Therapy for Osteosarcoma

Targeted therapy is a modern and promising approach that uses drugs acting directly on the molecular mechanisms of tumor cell growth and spread. These drugs specifically block proteins, enzymes, or receptors that the tumor needs to develop and progress.

Common Types of Targeted Drugs in Osteosarcoma Treatment:

• Tyrosine kinase inhibitors (e.g., pazopanib, regorafenib, sorafenib) – block signaling pathways the tumor uses to stimulate new blood vessel growth (angiogenesis), cutting off nutrients and slowing tumor growth.

• Monoclonal antibodies (e.g., denosumab) – target specific proteins on the tumor cell surface, inhibit their activity, and stimulate the immune system to fight cancer cells.

• mTOR inhibitors (e.g., everolimus) – block intracellular pathways involved in the growth and division of tumor cells, reducing tumor size and slowing growth.

Targeted therapy is most commonly used in patients with recurrent or metastatic osteosarcoma when traditional chemotherapy is not effective enough. Although many targeted drugs are still in clinical trials, initial results show significant potential to improve survival rates and quality of life.

In Russia, new treatment protocols and modern therapy schemes are actively being implemented, greatly improving the prognosis for osteosarcoma patients. The Marus digital platform can help organize osteosarcoma treatment by connecting you with the best specialists and clinics across the country.

Life After Osteosarcoma

After successful treatment, patients must undergo regular follow-up examinations. Rehabilitation programs are essential to restore limb function and adapt to new life circumstances, especially after amputation or prosthesis placement. Psychological support from specialists, family, and friends is also very important.

Prevention of Osteosarcoma

There is no specific prevention for osteosarcoma, but reducing exposure to risk factors and regular medical monitoring for those with genetic predispositions can help with early detection. It is also important to pay attention to bone pain in adolescents, as this may be an early sign of the disease. Caring for bone health, maintaining physical activity, and properly addressing injuries can help reduce the risks associated with osteosarcoma development.