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11 Cards in this Set
- Front
- Back
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Anatomy + Physiology |
Outer bone surface covered by a fibrous vascular layer known as periosteum to which tendons, ligaments and fascia are attached Vessels and connective tissue penetrate the cortex of the bone and arteries enter the medullary cavity throuhg nutrient foramina |
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Histology
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Most common Osteosarcoma (35%) Chondrosarcoma (25%) Ewing's Sarcoma (15%)
Osteosarcoma Arises in osteoblasts Presentation later in life associated with Paget's disease |
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Spread and Lymphatics |
Lymph Upper and lower extremity bones drain through nutrient foramina and traverse the periosteum, emptying into the nearest deep attaching trunk Lymphatic spread of bone tumours is uncommon. However, there is an increased risk where tumours present in the axial skeleton
Osteosarcoma Local spread: expands bone destroying the cortex and medulla, extending to surroundign soft tissue Metastatic: primarily to lung (80% have mets in 1-2 yrs)
Chondrosarcoma Loca: spread to adjacent joint and marrow cavity Mets: occurs late in high grade tumours to lungs Low grade tend not to met, but rather recur locally |
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Epidemiology and Aetiology |
Primary Bone Tumours Primary bones tumours are rare May be malignant or benign M>F Casuative factors widely unknown Prolonged growth or over stimualted metabolism, e.g. paget's disease, hyperparathyroidism and oesteomyelitis Radiation induced malignancy Chromosomal translocations
Osteosarcoma 10-20 yrs M>F Most commonly near epophyseal plates around the knee or proximal humerus Chondrosarcoma 30-50 y.o. |
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Tumour Origin |
Most commonly affects the extremities Typically present in the diaphysis of extremities with distal femur + proximal tibia most common Pelvis, spine, scapula, ribs and sternum
Chondrosarcoma Malignant tumoru of cartilage 50% in pelvis, femur, humerus and scapula |
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Staging |
1A/2A (T1N0M0): confined within cortex – low grade 1B/2B (T2N0M0): invades beyond cortex 3: not defined – high grade 4A: regional lymph node involvement 4B: distant metastasis
Low grade: exhibit well or moderately differentiated cells. The cell mitotic rate is slow and there is no necrosis High grade: poorly or un differentiated cells, a high mitotic rate and necrotic tissue |
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Clinical Presentations |
Pain Swelling Limp Pathological fracture Fever Fatigue Neurological symptoms if nerve compression |
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Detection and Diagnosis |
X-ray CT MRI Biopsy (MDT approach essential) FBC Radioisoptope bone scan Liver function tests |
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Disease Management |
Osteosarcoma Required a MDT Typically: Neo-adjuvant multi-agent chemotherapy Followed by conservative surgical resection of tumour Followed by post-operative chemotherapy Chemo: Adriamycin Methotrexate Cisplatin +/- ifosphamide Surgery Preservation of limb as much as possible Involved removal of diseased bone and replacement with bone graft or artificial prosthesis Contrainications: Extensive soft tissue involvement Neurological involvement Involvement of an ankle or humeral joint
Chondrosarcoma Radical srugery is treatment of choice Chemo has no effect |
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RT |
Only used for improving local control for incomplete resection of extremity tumours and vertebral and pelvic osteosarcoma Palliation Possible prophylactic pulmonary irradiation
Chondrosarcoma Option for recurrent, unresectable and incompletely resected tumours
Considerations Ensure adequate lymphatic drainage corridor over entire treatment length for limbs/extremities Field edges at well defined boen margin in uninvolved bones Skin dose in surgical site important consideration for wound healing
Prescription Pre-op: 50 Gy in 25 Tumours < 10 cm: CTV = GTV + 5 cm longitudinal margin >10 cm: GTV + 7-10 cm longitudinal margin 28-35 Gy with chemo Post-op: 66-70 Gy in 33-35# Ph 1: CTV + 5 cm longitudinal margin (<10 cm) or 7-10 cm (>10 cm). 45-50 Gy Ph2: GTV + 2 cm. 66-70 Gy Ph3: 1cm. 72-76 Gy |
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Prognosis |
Dependant upon chemo-related necrosis Survival improved in last 30 years due to more effective chemo agents Extremity prognosis better 60% 3 yr survival
Chondrosarcoma 65-80% 5 yr with resection alone Reduced to 35% for < 21 yrs |
