Osteosarcoma

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Osteosarcoma

• Paul Duffy

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Overview

• Definition
• Epidemiology
• Pathogenesis
• Skeletal distribution
• Clinical presentation
• Evaluation
• High grade osteosarcoma

• Parosteal osteosarcoma
• Periosteal osteosarcoma
• High grade surface osteosarcoma

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Definition

• 2nd most common primary bone tumor
• Malignant tumor of mesenchymal origin
• Spindle shaped cells that produce osteoid

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Epidemiology

• Any age
• 75 12-25yrs
• Modal incidence

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Epidemiology

• Primary vs secondary
• Male female
• Li Fraunie syndrome

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Pathogenesis

• Unknown
• Modal incidence correlates with rapid bone growth
• Radiation exposure
• Cancer survivors
• Retinoblastoma

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Skeletal distribution
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Classification
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Clinical Presentation

• Painful mass arising from bone
• Trauma
• Metastisize early in evolution
• 20 clinically detectable mets at dx

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Evaluation

• Suspected diagnosis by hx and physical
• Supported by xray

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Plain Xray

• Lytic, sclerotic or mixed
• Typical characteristics of malignant tumor
• Ennekings 4 questions

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Initial Evaluation

• Define the extent of the disease
• Locally
• Systemically

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Local

• CT
• MRI
• /- Angiogram

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CT
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MRI
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Angio
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Systemic

• Bone scan
• CT Chest
• lab

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Classic High Grade Osteosarc

• Age, sex
• Presentation
• Physical exam
• Blood work
• Plain films
• Site
• size

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Differential Dx

• Giant Cell Tumor
• Aneursymal Bone Cyst
• Ewings
• Osteoblastoma
• Metastasis
• Lymphoma

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Biopsy

• Principles
• Dx high grade osteosarcoma
• Now What??

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Chemotherapy

• Micro metastasis
• What we have learned pre chemo (1970s)
• Multi Institutional Osteosarcoma Study

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Chemotherapy

• Chemo cannot control clinically detectable
  disease
• Radiation is ineffective
• Local control is surgical

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Chemotherapy

• Best protocol is subject of ongoing trials
• Drugs
• Doxorubicin
• Cisplatin
• Ifosfamide
• Methotrexate
• Cyclophosphamide
• Side effects

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Induction Chemotherapy

• Arose in conjunction with development of limb
  sparing surgery
• Increase survival
• prognostic

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Surgery

• Limb salvage the norm
• Now safer procedure
• Wide surgical margin

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Surgical options

• Articular surface removed
• Osteoarticular allograft replacement
• Custom modular prosthesis
• Allograft prosthesis composite
• Allograft arthodesis
• Segment of diaphysis missing
• Intercalary allograft

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Surgery

• Young patient with open growth plate
• Rotatioplasty
• Conventional amputation

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Surgery

• Indication for amputation
• Grossly displaced pathologic fracture
• Encasement of neurovascular bundle
• Tumor that enlarges during preop chemo and is
  adjacent to neurovascular bundle

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Current Standard of Care

• Pretreatment radiologic staging
• Bx to confirm diagnosis
• Preoperative chemotherapy
• Repeat radiologic staging
• (access chemo response, finalize surgical tx
  plan)
• Surgical resection with wide margin
• Reconstruction using one of many technoques
• Post op chemo based on preop response

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Surface osteosarcoma

• Parosteal
• Periosteal
• High grade surface osteosarcoma

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Parosteal

• 5 of osteosarcomas
• Posterior metaphysis of distal femur
• Slow growing large ossified mass
• Confused with osteochondroma
• String sign
• Low grade
• treatment

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Parosteal Osteosarcoma
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Parosteal Osteosarcoma
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Periosteal Osteosarcoma

• Arises from surface of diaphysis
• Characterized by bony spicule formation
  perpendicular to shaft
• Sunburst
• Low grade
• Wide excision

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High grade surface

• Very rare
• 20-30s
• Appearance as parosteal but histology high grade
• Tx as classic intermedullary