Osteosarcoma: Causes, Symptoms, Diagnosis and Treatment — Overview, Diagnosis & Treatment Options | MyMedicPlus

Osteosarcoma is the most common primary malignant bone tumor, predominantly affecting adolescents aged 10-20 during growth spurts and adults over 60. It most often arises in the metaphyses of long bones: distal femur, proximal tibia, and proximal humerus.

Most cases are sporadic. Risk factors include rapid bone growth, prior radiation therapy, Li-Fraumeni syndrome (TP53 mutation), Rothmund-Thomson syndrome, hereditary retinoblastoma (RB1 mutation), and Paget's disease of bone in older adults.

Localized bone pain (often worse at night and initially attributed to growing pains), swelling or soft tissue mass over the affected bone, restricted joint movement, and pathological fracture in advanced cases. Constitutional symptoms are uncommon.

Plain X-rays show classic sunburst pattern and Codman's triangle (periosteal reaction). MRI defines local extent for surgical planning. CT chest detects pulmonary metastases. Biopsy confirms diagnosis. Alkaline phosphatase and LDH serve as prognostic markers.

Neoadjuvant chemotherapy (MAP: high-dose methotrexate, doxorubicin, cisplatin) followed by limb-salvage surgery or amputation, then adjuvant chemotherapy. Mifamurtide is added in some protocols. Lung metastasectomy is performed for isolated pulmonary disease.

Localized disease: 5-year survival approximately 60-70%. Metastatic disease: 5-year survival approximately 20%. Histological response to neoadjuvant chemotherapy (>90% tumor necrosis) is the strongest prognostic factor and guides post-operative chemotherapy selection.