--- title: Osteosarcoma url: "https://www.yyhmedical.com/en/guide/solid/disease-osteosarcoma" type: MedicalWebPage inLanguage: en-US --- # Osteosarcoma > Osteosarcoma is a malignant bone tumor in which cancer cells directly produce osteoid or immature bone. It is one of the most common primary malignant bone tumors in children and adolescents, although it can also occur in adults. ## Overview Osteosarcoma arises from mesenchymal cells capable of forming bone. Its defining pathologic feature is the production of osteoid by malignant tumor cells. It occurs most often during periods of rapid growth in adolescence. Common sites include the distal femur, proximal tibia, and proximal humerus—the long bones near the knee and shoulder. Osteosarcoma can also occur in adults. In some older adults, it may be associated with conditions such as prior radiation therapy or Paget disease of bone. There are several histologic subtypes. Conventional high-grade osteosarcoma is the most common. Some low-grade forms, such as parosteal osteosarcoma, tend to behave less aggressively and may be treated differently from conventional high-grade disease. ## Causes and Risk Factors Most people with osteosarcoma do not have an identifiable cause. Factors associated with an increased risk include: - Periods of rapid bone growth during adolescence - Previous radiation therapy - Certain inherited cancer-predisposition syndromes, including Li-Fraumeni syndrome and hereditary retinoblastoma - Paget disease of bone, particularly in some older adults - A small number of other inherited or bone disorders Trauma is not considered a cause of osteosarcoma. Sometimes an injury draws attention to persistent pain in an area where a tumor was already present, which can create the impression that the injury caused the cancer. Taller height or rapid adolescent growth has been associated with risk in some studies, but being tall itself does not cause osteosarcoma. ## Signs and Symptoms The most common symptom of osteosarcoma is pain in the affected bone. At first, pain may come and go. Over time, it may become more persistent or severe and can sometimes be worse at night or with activity. Other possible symptoms include: - Local swelling or a noticeable mass - Tenderness - Reduced movement near a joint - Limping or avoiding weight-bearing on the affected limb - Reduced muscle strength - A pathologic fracture Patients with localized osteosarcoma do not necessarily feel generally unwell at diagnosis. Many have only local symptoms such as pain and swelling. Fever, marked weight loss, anemia, and severe weakness are not typical early features. ## Diagnosis Diagnosis of osteosarcoma combines clinical evaluation, imaging, and biopsy. X-rays are often the first imaging study. Osteosarcoma may cause bone destruction, abnormal new bone formation, and characteristic periosteal changes. MRI is important for defining the full extent of the primary tumor within the bone and surrounding soft tissues and for assessing its relationship to nearby joints, blood vessels, and nerves. Staging tests are also needed to determine whether the cancer has spread. The lungs are the most common site of distant metastasis, so chest CT is commonly performed. PET/CT, bone scanning, or other whole-body imaging may also be used depending on the clinical situation. A biopsy is required to confirm the diagnosis. The biopsy should ideally be planned by a multidisciplinary bone tumor team before definitive surgery. The location of the biopsy tract can affect later tumor removal and limb-sparing surgery, so careful planning is important. Core needle biopsy is commonly used, while an open biopsy may be performed in selected situations. Blood tests may include a complete blood count, liver and kidney function tests, alkaline phosphatase, and lactate dehydrogenase. These tests help assess overall health and may provide additional clinical information, but they cannot diagnose osteosarcoma on their own. ## Treatment **Chemotherapy** Most patients with localized high-grade osteosarcoma receive systemic chemotherapy. Treatment commonly begins with chemotherapy before surgery, followed by definitive surgery and additional chemotherapy afterward. Frequently used drugs include high-dose methotrexate, doxorubicin, and cisplatin. Ifosfamide and other agents may also be used in selected situations. The exact regimen depends on age, tumor characteristics, overall health, and the treatment center. Preoperative chemotherapy treats possible microscopic disease elsewhere in the body and allows doctors to assess how well the tumor responded when the surgical specimen is examined. ### **Surgery** The goal of surgery is to completely remove the tumor with adequate margins while preserving as much function as safely possible. Today, most patients with osteosarcoma of an arm or leg can be treated with limb-sparing surgery. According to the NCI, more than 80% of patients with extremity osteosarcoma can undergo a limb-sparing procedure rather than amputation. Whether limb-sparing surgery is appropriate depends on the tumor's size and location, involvement of major nerves or blood vessels, the ability to achieve adequate surgical margins, expected function, and the patient's overall condition. ### ****Metastatic Osteosarcoma**** The lungs are the most common site of metastasis, although osteosarcoma can also spread to other bones. The presence of lung metastases at diagnosis does not automatically rule out intensive treatment. For selected patients, treatment may still include systemic chemotherapy, complete removal of the primary tumor, and surgical removal of lung metastases. The ability to completely remove all detectable disease is an important factor associated with long-term disease control. ### ****Recurrent Osteosarcoma**** Osteosarcoma most often recurs in the lungs, but it may also return at the original site or in other bones. For recurrent disease, one of the first questions is whether all detectable tumors can be completely removed. Patients with a small number of resectable lung metastases may still achieve long-term disease control after complete surgical resection. When complete surgery is not possible or the cancer has recurred multiple times, options may include additional chemotherapy, radiation therapy, selected targeted therapies, and clinical trials. There is no single standard drug regimen that works for every patient with recurrent osteosarcoma, making clinical trials particularly important in this setting. ### **Radiation Therapy** Osteosarcoma is relatively resistant to conventional radiation therapy, so radiation is not usually the main treatment when the tumor can be completely removed surgically. However, radiation may be useful when surgery is not possible, when surgical margins are inadequate, or for local control and symptom relief in recurrent or metastatic disease. ## Content attribution (YMYL) - Author: - Medically reviewed by: - Last reviewed: - First published: > --- Original (HTML):https://www.yyhmedical.com/en/guide/solid/disease-osteosarcoma This is a clean Markdown mirror for large language models; the original page is authoritative.