PAMS: Ortho- Bone Tumors Flashcards
What are the origins of Primary Malignant Bone tumours?
- Hematopoietic > 40%
- Chondrogenic > 20%
- Osteogenic > 20%
- Unknown 10%
What are the 3 Most Common Malignant tumours of
Bone ?
- Osteosarcoma
- Chondrosarcoma
- Ewing sarcoma
What are the risk factors for osteosarcoma ?
- Retinoblastoma
- Hx of radiation tx
- Hx of high bone turnover (e.g., Paget Disease of Bone)
What are the most common locations of osteosarcoma ?
Distal femur and proximal tibia = 60%
Proximal femur =15%
Proximal humerus = 10%
Mandible = 8%
What is the epidemiology of osteosarcoma ?
It is more common in boys than girl. It accounts for 50% of bone cancers in those <20 years. It is also the 5th most common cancer between 15-19 year olds.
What are the symptoms of osteosarcoma?
Dull aching pain over the involved area, night pain and growing pain with or without B symptoms.
What are the signs of Osteosarcoma ?
Patients often have tenderness to palpation on the involved area. Limited AROM of adjacent joints. They may also present with or without swelling, mass, deformity or Spontaneous fracture.
What are the imaging studies in osteosarcoma?
- Regional MRI and CT helpful for
guiding surgical repair. - Evaluation for metastatic pulmonary
disease - Pre-op: All patients get chest CT
- Post-op: Repeat chest CT q 3-6 mo x 2 yr.
- Bone scintigraphy: May show distant metastatic lesions or local invasion.
What is the significance of biopsy in osteosarcoma?
Percutaneous needle biopsy is sufficient to make the diagnosis and staging.
What is the Enneking System for Staging Osteosarcomas?
Stage 1: Low grade no mets,
1A- intra compartmental and 1B extra compartmental.
Stage 2: High grade no mets, IIA intra compartmental and IIB extra compartmental.
Stage 03: Low or High grade with Mets.
What is the Tx of osteosarcoma ?
Methotrexate, Doxorubicin, and Cisplatin for 10 week, Surgery on the 11th week, followed by same chemo protocol for a year.
What should be the post surgical follow up in osteosarcoma patients ?
There is 70 to 85% long-term survival rate in osteosarcoma. However relapses are common therefore monitoring as follows is essential:
* In the first year blood work and imaging every 3 months.
* Same screening continued every 6 months for the next 2 years.
* Then yearly.
* Chest CT must be done every 6 months for the first 2 years due to the risk of mets into the lungs.
What is the prognosis of Osteosarcoma?
- 5-Year survival – 70%
- Influenced by metastases at time of diagnosis
- Response to neoadjuvant chemo is major prognostic indicator
What is the pathophysiology of osteosarcoma?
The pathogenesis of osteosarcoma consist of RB and tp53 mutations triggering uncontrolled proliferation of pleomorphic osteoblasts around the metaphysis of the long bones such as tibia and fibula leading to the symptomatology and radiological sunburst appearance and Codman’s triangle.
What is a chondrosarcoma ?
It is a cartilaginous tumor and is the 3rd most common bone malignancy after multiple myeloma and osteosarcoma. 90% are conventional chondrosarcomas followed by dedifferentiated, clear cell, mesenchymal, and juxtacortical subtypes. Secondary chondrosarcoma can arise from enchondroma or osteochondromas.
