Osteosarcomas Flashcards
(20 cards)
Where does OSA more commonly occur?
“Away from the elbow and towards the knee”
Forelimbs > hindlimbs (radius and humerus)
What is the biologic behavior of OSA?
<10% pulmonary metastasis at diagnosis
No treatment = 4-7m survival
>90% will die of metastasis by 1 year with amputation alone
Clinical Signs: OSA
Lameness, mass on limb
+/- trauma, acute onset
Palpable mass on rib or flat bone
Dysphagia, exophthalmos, facial deformity, paresis/paralysis
What are the differential diagnoses for OSA?
Osteomyelitis
Metastatic tumor
Other primary bone tumor
Diagnostics: OSA
Limb rads (not as sensitive, need 40% cortical bone loss before visible)
CT more sensitive
FNA (ALP stain)
Biopsy
What are radiographic features of OSA?
Cortical lysis
Metaphysis
Lytic or blastic
Sunburst pattern
Codman’s triangle
Doesn’t cross joint
How do we determine where OSA is located?
3V thoracic rads
Ortho exam
PET CT
What are the 2 methods for bone biopsy collection?
Open: wedge, trephine, +/- currette
Closed: jamshidi
Define: Curative Intent Therapy
Use multiple therapies to achieve the longest survival with the best possible quality of life
Death more commonly due to metastatic disease
Define: Palliative Intent Therapy
Accept progression of disease - therapy aimed at alleviating signs only
Death more commonly due to local disease
What is the prognosis for OSA with palliation, amputation, and amputation + chemo?
Palliation: 1-2 months
Amputation: 4-7 months
Amputation + chemo: 10-16 months
What are the contraindications to amputation with OSA?
Progressive neurologic disease
Prior amputation of another limb
Severe orthopedic condition
Owner will not permit
What is the traditional limb salvage surgery candidate?
Disease confined to leg
Histologically confirmed tumor
Tumor affects <50% of the bone
Good general health
No pathologic fracture
Distal radius
What are favorable vs unfavorable locations for limb salvage surgery?
Favorable: distal radius, ulna, scapula
Unfavorable: stifle, tibia, humerus
What are the recommended surgical margins for resection of the osteosarcoma tumor in traditional limb salvage surgery?
3cm bone margins
1 fascial plane surrounding
Define: Bone Transport Osteogenesis
Induction of new bone formation between bone surfaces that are gradually pulled apart
What is the role of radiation therapy AFTER limb amputation in the treatment of appendicular OSA?
It is not indicated as amputation is a wide local or radical excision
What is the role of adjuvant chemotherapy with OSA? What is the chemotherapy of choice?
Regardless of surgery performed, dogs with OSA need chemotherapy to extend survival
Carboplatin (300mg/m2 q 21d) x 4-6
What do dogs most typically die of when receiving palliative care for an appendicular osteosarcoma?
Euthanasia as a result of the local tumor (such as increasing tumor pain or pathologic fracture)
What procedure has been shown effective for treatment of hypertrophic osteopathy secondary to pulmonary OSA metastasis?
Metastectomy
