Tumors Of The Appendicular Skeleton- Osteosarcoma Flashcards
What’s the signalment for OSA?
Large to Giant breeds (>40 kg)
— Irish wolfhounds, GSD, Great Danes, greyhounds
Male predisposition but gonadectomized are 2x increased risk (esp. rotties)
Bimodal distribution: 1-2y; 7-9y
What is the most common site for OSA?
Distal radius,
Then proximal humerus…
(Away from the elbow, twd the knee)
Distal femur,
proximal tibia
What part of the bone is favored in development of OSA?
Metaphyseal region
What might be elevated on chemistry profile in a dog with OSA?
ALP!
What is Codman’s triangle?
Periosteal lifting caused by subperiosteal hemorrhage
As the tumor is moving from the endosteal surface out, it can disrupt the periosteum, and it can pop up the periosteum from hemorrhage..
T or F: OSA sometimes spans across joints from one bone to another.
FALSE. Does NOT cross joints!
What is the prognosis for OSA if the patient is provided with palliative care (analgesia) only?
MST: 1-3 months
*RT MST: 4-10 months*
What’s the prognosis for OSA if the patient undergoes curative intent Stereotactic Radiosurgery (SRS) alone?
MST: 4-6 months
What’s the prognosis for OSA if the patient undergoes surgery (or SRS) and chemotherapy?
MST: 8-12 months
For every _____U/L increase in total ALP increases the risk of tumor-related death by _____%.
100; 25
T or F: FNA/cytology is preferred over biopsy in the diagnostic algorithm for OSA.
True
In the case of a proximal femoral OSA lesion, what are the more “aggressive” surgeries we would need to implement for local control?
En-bloc acetabulectomy OR Subtotal hemipelvectomy
With regard to OSA amputation results, thoracic limb amputees tend to have more difficulty in _______________ , whereas pelvic limb amputees have more difficulty __________.
Keeping balance; Gaining speed
Severe osteoarthritis,
Neurological disease,
Morbid obesity
(in an existing OSA case) Are all indications for ….?
Limb salvage!
Pathological fracture,
Extensive soft-tissue involvement,
Poorly compliant owner or patient,
Large lesion >50% diaphysis,
Advanced disease,
And inappropriate location of tumor
(in an existing OSA case) Are all indications for what?
They’re CONTRAindications for limb salvage!
What’s the preferred site for surgical limb salvage?
Distal radius (most common site of tumor occurrence)
How can isolated ulnar lesions be treated?
Ulnectomy! Including the excision of styloid process (Distal location preferred)
In the cases of limb salvage surgery, what adjunctive therapy needs to follow?
Cytotoxic chemotherapy!
What is stereotactic radiosurgery (SRS)?
Entire radiation dose is delivered in a single treatment through the use of multiple, noncoplanar beams of radiation that are stereotactically focused on the target…
What are the major benefits of SRS?
Minimizes damage to healthy surrounding tissues by relying on extreme accuracy of radiation delivery to a tumor,
Steep dose gradient between the tumor and surrounding healthy tissues…
What is the best site for SRS based on low P.O. fracture rate in limb salvage?
Proximal humerus
What are the adjunctive chemotherapy options for OSA?
Cisplatin, Carboplatin, Doxorubicin
How do amino-bisphosphonates exert their effect?
They act on osteoclasts via inhibition of the mevalonate pathways, which results in disruption of intracellular signaling and induction of apoptosis.
Zoledronate and Pamidronate are examples of ?
Aminobisphoshonates… Demonstrated pain palliation in 30-50% of treated dogs
How does RT provide palliative therapy in OSA patients?
Reduces local inflammation, minimizes pain, slows progression of metastatic lesions, improves QOL
Development >300 days after initial diagnosis,
<3 radiographically evident metastatic lesions,
And no doubling in size of lesions or development of new lesions in a 4-week period
(in an existing OSA case) Are indications for what?
Pulmonary metastatectomy
What part of the bone is OSA more common in the feline?
Diaphysis
MST for OSA when providing only palliative care…?
1-3 months
MST for OSA when treated surgically alone…?
4-6 months
MST for OSA when surgery and chemotherapy are combined in treatment…?
8-12 months
T or F:
Cats with appendicular OSA may be cured with amputation alone (no chemo).
True.
MST: 24-49 months
