Osteosarcoma

Epidemiology
Most common primary bone tumor of children
700 cases per year
Slightly more common in boys
No racial differences
Adolescents

Risk factors
Prior RT
Hereditary retinoblastoma
Li-Fraumeni syndrome
Paget's disease (adults)

Pathology
Classic: higher grade
Periosteal: variant of classic
Parosteal: indolent, few mets

Clinical
Metaphysis of long bones
40% occur in the femur
90% of tumors are in the extremities
Codman's triangle = periosteal elevation
15% have mets at diagnosis, most common site is lung
Head and neck osteosarcoma seen more frequently in adult patients (mandible/maxilla); poor control with surgery alone and patients should receive chemotherapy
Pelvic and spine tumors are also more difficult to control (but rare)

Prognostic factors
Stage
Extent of necrosis after chemo

Therapy
1) Induction chemo: methotrexate, cisplatin, adriamycin, ifosfamide
2) Resection
3) More chemo

RT: Only for unresectable tumors, positive margin after surgery, palliation
Cade technique: RT with delayed amputation