What are bone sarcomas
Sarcomas are heterogeneous groups of tumors that encompass three major groups: soft tissue, bone, and GIST (tumor of the gastrointestinal stroma). They are tumors originating from the disordered growth of bone cells and can affect any bone in the body.
They are rare tumors, with an incidence around 0.2% of all cancers in adults. In Brazil, there are few epidemiological studies on the disease, but a comparison of regional data with international databases shows that in the country the incidence and prognosis are similar to the rest of the world. Cooperation initiatives between physicians and patients from different parts of the world are extremely important for a better understanding and management of this disease.
The causes of sarcomas are unknown in most patients, although a small percentage are related to factors such as inherited genetic syndromes (such as neurofibromatosis or von Recklinghausen disease, Gardner syndrome, Li-Fraumeni syndrome, retinoblastoma, Werner syndrome, Gorlin syndrome, and tuberous sclerosis), exposure to radiation and chemical agents.
Subtypes of bone sarcomas
The classification of bone tumors takes into consideration the tissues produced by the tumors. The main types are:
- Osteosarcoma – is the most common type of bone sarcoma. It most commonly affects children, adolescents, and young adults. It usually occurs in long bones, such as the femur, arm bones, and pelvis;
- Ewing Tumor or Ewing Sarcoma – is the second most common type of malignant bone tumor and affects children most often. The areas where it usually appears are the femur and pelvis regions. Highly aggressive, it can also develop in soft tissue such as muscle and cartilage; and
- Chondrosarcoma – the fundamental tissue of this type of bone tumor is formed by cartilage. It appears most frequently in long bones and the pelvis.
Besides the three most frequent types, other subtypes, such as pleomorphic sarcoma of bone, fibrosarcoma, giant cell bone tumor, and chordoma, are part of this very heterogeneous group.
Symptoms and signs of bone sarcomas
Pain, swelling in the affected region, and fracture are the most commonly found symptoms in patients with bone sarcoma. Fever may accompany the condition.
Some cases may be asymptomatic, with the tumor being a chance found in some routine examination.
Diagnosis of bone sarcomas
Diagnosis of bone tumors begins with clinical examination and imaging tests such as X-ray, CT scan, MRI, and bone scintigraphy.
After the imaging analysis, the diagnosis is closed by means of biopsy, which consists of taking a piece of the tumor and laboratory analysis to confirm the subtype, aggressiveness degree, and molecular characteristics that can help in the treatment.
The low incidence, its wide spectrum of subtypes, biological behavior, and ubiquity make the management of osteosarcomas challenging. Therefore, treatment should be carried out in a multidisciplinary environment with teams of experienced specialists.
Treatment depends on the type, size and area of the tumor and may use the three most common modalities in oncology:
Besides controlling the disease, preserving the limb with good motor function is one of the main goals of the treatment, and the approach is individualized for each patient.
Most bone sarcomas have no known risk factor, which makes prevention difficult. There is no routine test to help detect the disease.
For those who carry the inherited genetic syndromes related to bone tumors, regular screening exams can help with early diagnosis and result in a greater chance of cure upon treatment.