Intro
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- Group of malignant tumors that arises from mesenchymal/ mesoderm/ connective tissue.
- As opposed to carcinomas which are from epithelial tissues
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- Longitudinal
- Transverse – Eccentric? Central?
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- Lytic/ Expansile/ Sclerotic
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- Bone to lesion Zone of transition – wide or narrow
- Lodwick classification - Geographical, Moth eaten, Permeative
- Periosteal reaction types
- Onion skinning = Ewing
- Sunburst
- Codman’s Triangle = lifting of the periosteum
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- Osteoid/ chondroid/ ground glass
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- [FASTEST] Sunburst reaction = ossification of Sharpey’s fibers!
- Onion skinning
- [SLOWEST] Codman triangle = Periosteum lifted up, has time for periosteum to lay down subperiosteal bone
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- 1 = Latent – UBC (if normal bone separates cyst from physis),Enchondroma, NOF, Osteochondroma
- 2 = Active – UBC (if adjacent to physis), Osteoid Osteoma
- 3 = Aggressive – GCT, ABC, Chondroblastoma, Osteoblastoma (aggressive variant), Chondromyxoid Fibroma (CMF),
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- 1 = Low Grade
- 2 = High Grade
- 3 = Mets
- Modifier A/ B = intra or extracompartmental
- (skip lesions = B)
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- Hx = Duration, red flags symptoms, Pain
- PE = Features of infection
- Invx = "bloods and imaging and biopsy TRO infection and to diagnose and tumor"
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- FETISH
- Fracture, EG, Tumor, Infection, Steroids, Hemangioma
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- Ewing t(11;12) (q24;q12)
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- Chondroblastoma, GCT
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- GOATS-CSF - 7
- G: GCT [aggressive]
- O: Osteoblastoma [aggressive]
- A: ABC [aggressive]
- T: Telengiectatic Osteosarcoma
- S: Sarcoma
- C: Chondroblastoma [aggressive]
- S: Solitary bone cyst with fracture
- F: Fibroxanthoma
- Note that 4 of which are aggressive by enneking classification
- https://radiopaedia.org/articles/fluid-fluid-level-containing-bone-lesions-mnemonic
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- Leukemia/ Lymphoma/ infection, Mets from Neuroblastoma
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- Vertebral body - GCT, EG (Vertebral plana)
- Posterior elements - ABC, OB, OO, OC
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- 1. Ganglion cyst
- 2. PVNS/ GCT of tendon sheath
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RADIO AND CHEMOTHERAPY
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- 2 mechanisms - indirect and direct
- Indirect - Radiation produces free radicals in tumor and adjacent cells causing DNA damage and apoptosis
- Direct - direct ionization of atoms in the DNA chain
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- cEBRT (Conventional External beam radiation therapy) - delievers radiation
- IGRT (Image guided radiation therapy) or stereotactic Body Radio therapy (SBRT)
- Able to deliver high doses of radiation in close proximity to the spinal cord while maintaining radiation exposure of spinal cord and other adjacent vital structures within limits of safety.
- Brachytherapy - radiation source inside or next to area requiring treatemnt - e.g. for rectum and cervix
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- 1 rad = 1centi Gray = 0.01 Gray
- Typical dose is 2 gray/day (200cGy/day )
- Total dose to treat bone tumors:
- Osteosarcoma - median dose is 55.8 Gy
- So e.g. this works out to about 30 sessions of 2gray / day But this is done over 6 weeks
- This allows normal tissue to recover from radiation damage
- Dose-response tissue healing (TOTAL for whole course) i.e. radiotherapy is cumulative
- < 45 Gray = uncomplicated tissue healing
- 45 - 55 Gray = tissue heals but w problems
- More than 60 Gray = Tissue likely will not heal
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- Soft tissue
- Early - delayed wound healing • infection
- Late - fibrosis • joint stiffness
- Post-radiation Sarcoma ~10%!
- Post-Radiation fractures
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- DCMI port
- Doxorubicin (antitumor antibiotics that attach to DNA)
- Cisplatin (Alkylating agent that damages DNA)
- Methotextrate (Antimetabolite folate analog)
- Ifosamide