Osteosarcoma

What it is

Overview

Osteosarcoma is the most common primary bone cancer and most often affects children and adolescents during periods of rapid bone growth. It typically develops near the growth plates of the long bones — the knee (distal femur, proximal tibia) and the shoulder (proximal humerus). Treatment requires surgery and chemotherapy, and outcomes depend heavily on whether the cancer has spread at diagnosis.

Biology

How It Develops

Osteosarcoma arises from osteoblasts (bone-forming cells) that develop mutations, often involving the RB1 and TP53 tumor suppressor genes. The adolescent growth spurt — with its rapid bone remodeling — creates conditions where these mutations can emerge. Prior radiation exposure and genetic syndromes significantly increase risk.

Warning signs

Symptoms

• —Pain and swelling near a bone or joint
• —Bone pain that worsens at night or with activity
• —A lump or mass on a bone
• —Fracture from minor injury (pathologic fracture)
• —Limited range of motion in a joint

Detection

Diagnosis Methods

• —X-ray (sunburst pattern is characteristic)
• —MRI for local extent
• —CT of chest (for lung metastases)
• —Bone scan or PET
• —Bone biopsy (open or needle)
• —Alkaline phosphatase and LDH blood tests

Medical care

Treatment Options

• —Neoadjuvant chemotherapy (MAP: methotrexate, doxorubicin, cisplatin)
• —Surgery (limb-sparing resection or amputation)
• —Adjuvant chemotherapy
• —Lung resection for pulmonary metastases
• —Clinical trials (immunotherapy, targeted therapy)

Data

Statistics

Prevention

Risk Factors

• —Adolescence and male sex
• —Tall stature and rapid bone growth
• —Retinoblastoma (germline RB1 mutation)
• —Li-Fraumeni syndrome (TP53 mutation)
• —Prior radiation therapy

Further reading

Resources