OSA Flashcards
For canine OSA limb spare: % local recurrence? 1 yr recurrence rate? % local infection? effect of local infection?
21-24%
32%
31-41%
dogs w infection live longer 11 v 5 mos
MSTs for canine OSA limb spare:
Sx + RT
Sx + chemo
Sx + chemo + RT
6, 14, 8-9
Four conditions to be a candidate for limb spare:
- radiographically effects < 50 % of bone
- good health otherwise
- ST involvement < 360º √√√
- no fx
IORT MST for OSA?
10 ms
SRS for OSA:
MST?
% improvement in lameness & swelling?
% developed pathologic fx?
12 mos
100%
36%
DRT for OSA: MST? Median local control time? \_\_\_to \_\_\_% clinical improvement in \_\_to\_\_days Advantage over PRT?
5-7 mos
7 mos
74 to 92….2 to 16
none
PRT for OSA:
MST?
___-___% clinical improvement
median duration of response?
3-6 mos
80 to 91
2-4 mos √√√
PRT + chemo for OSA MST
2.5-10 mos
PRT + chemo for OSA:
Stage III MST?
Mets to bone vs mets to lung MST?
2 mos
dogs w bone mets lived longer (4.4 vs 2 mos)
PRT + chemo for OSA:
Range of % responded to RT?
median duration of response?
74-92%
2-3 mos
PRT with photons + chemo for OSA:
Dogs receiving chemo were ___x more likely to achieve response
Effect of chemo on duration of response?
Effect of chemo on survival
3.5
longer duration of response
longer survival
Regarding OSA and PRT, what was the difference in survival for RT alone vs RT + chemo w electrons
none
In PRT for OSA, lesions in what location have the LONGEST duration of response?
proximal humerus
In canine OSA, what is the effect of % bone involvement on MST
Controversial
If >42% involvement, worse px in one study
In dogs w OSA, there is decreased response to RT in what 2 situations?
Non-wt bearing at tx
On opioids
What does RT do in OSA (cellular level)?
Induces apoptosis in osteoblast & osteoclasts
Pamidronate:
Inhibits _____w/o inhibiting_____.
Causes apoptosis of _______, resulting in decreased_______.
Interfere with ______ of small GTP binding proteins (__,___,___), leading to failure of _____ & interaction with the ___, triggering ___
bone resorption…bone mineralization
osteoclasts…..pathologic bone resorption
post-translational prenylation….Ras, Rho, Ree
normal intracellular signaling…ECM…apoptosis
Pamidronate in OSA:
% response
% pain alleviation
28, 40
Pamidronate effects on:
urine NTx
rBMD
decrease
increases
NTx - global indication of bone resorption
rBMD - indicator of focal bone lysis
Do DEXA scans and NTx correlate w clinical response to pamidronate in OSA?
DEXA does, NTx does not
Response of OSA to Zoledronate
50%
100x greater antiresporptive potency than pamidronate
In one study, dogs that received pamidronate had decreased survival…___mos vs. ___mos.
RT+ pamidronate = ___mos.
RT+ pamidronate + chemo = ____mos.
4 vs 8
2
7
Samarium:
Emits what type of radiation?
Range of effect (distance)?
half-life?
ß emitter w a gamma photon coupled to EDTMP
2-3mm
gamma allows visualization
1.9 days
Samarium:
Localization?
Main adverse event?
- concentrates in areas of increase osteoblastic activity and binds to exposed hydroxyapatite crystals.
- Myelosuppression
In axial OSA of the dog, MST for DRT and PRT?
9 mos, 3-5 mos
Dogs treated w DRT lived sig longer than dogs treated w PRT√√√
Is chemo beneficial in the tx of axial OSA?
Yes - chemo should be included in definitive tx regime
MSTs of various OSAs: Mandible Maxilla Extraskeletal Vertebral Rib Skull
Mandible: 13-18 mos (sx alone) Maxilla: 5-10 mos (sx alone) ES: 1 mos sx; 5 mos if add chemo Vert: 4 mos RT+Sx+chemo Rib: 3 mos sx, 8 mos sx + chemo Skull: 7 mos
Generally, OSA is most common in what part of the skeleton, what region of the bone, and FORE vs. HIND?
appendicular
metaphyseal
forelimb 2 x as likely as hindlimb
Metastasis of OSA is promoted by what protein?
Ezrin (cytoskeltal linker protein)
Does pathological fx presentation carry a worse prognosis in OSA?
No
What % of dogs with OSA have radiographic evidence of bone or lung mets at dx?
What % of dogs have micro mets at time of dx?
Less than 15%
Greater than 90%
What % of dogs with OSA will die ≤ 1 year w metastatic disease w amputation alone; MST of _____?
90%
4 mos
What is the significance of elevated serum or bone ALP in OSA?
What is the significance of failure of ALP to return to normal w/in 40 days of Sx?
Associated w shorter DFI & survival.
Develop earlier metastasis
What is the significance of the following markers in OSA? Ezrin Survivin VEGF COX-2 staining IGF-2 & alcohol dehydrogenase RON
Ezrin: high, shorter mDFI Survivin: low, longer DFI VEGF: high, shorter DFI COX-2 staining: strong, shorter MST IGF-2 & alcohol dehydrogenase: downregulated, shorter DFI √√√ RON: high, live shorter time (MET not prognostic)
In general, survival for OSA in dogs:
Chemo + amputation?
Pain meds?
surgery alone?
8-12 mos
1-3 mos
3-6 mos
Is feline OSA more likely to be in forelimb or hindlimb?
1.6 times more likely in hindlimbs
MSTs for feline OSA w Sx alone:
appendicular
axial
extraskeletal
24-49 mos
6 mos
12 mos
Is chemo recommended for feline OSA?
No…10% metastatic rate
