OSA

Question 0

For canine OSA limb spare:
% local recurrence?
1 yr recurrence rate?
% local infection?
effect of local infection?

Answer 0

21-24%
32%
31-41%
dogs w infection live longer 11 v 5 mos

Question 1

MSTs for canine OSA limb spare:
Sx + RT
Sx + chemo
Sx + chemo + RT

Answer 1

6, 14, 8-9

Question 2

Four conditions to be a candidate for limb spare:

Answer 2

1. radiographically effects < 50 % of bone
2. good health otherwise
3. ST involvement < 360º √√√
4. no fx

Question 3

IORT MST for OSA?

Answer 3

10 ms

Question 4

SRS for OSA:
MST?
% improvement in lameness & swelling?
% developed pathologic fx?

Answer 4

12 mos
100%
36%

Question 5

DRT for OSA:
MST?
Median local control time?
\_\_\_to \_\_\_% clinical improvement in \_\_to\_\_days
Advantage over PRT?

Answer 5

5-7 mos
7 mos
74 to 92….2 to 16
none

Question 6

PRT for OSA:
MST?
___-___% clinical improvement
median duration of response?

Answer 6

3-6 mos
80 to 91
2-4 mos √√√

Question 7

PRT + chemo for OSA MST

Answer 7

2.5-10 mos

Question 8

PRT + chemo for OSA:
Stage III MST?
Mets to bone vs mets to lung MST?

Answer 8

2 mos

dogs w bone mets lived longer (4.4 vs 2 mos)

Question 9

PRT + chemo for OSA:
Range of % responded to RT?
median duration of response?

Answer 9

74-92%

2-3 mos

Question 10

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

Answer 10

3.5
longer duration of response
longer survival

Question 11

Regarding OSA and PRT, what was the difference in survival for RT alone vs RT + chemo w electrons

Answer 11

none

Question 12

In PRT for OSA, lesions in what location have the LONGEST duration of response?

Answer 12

proximal humerus

Question 13

In canine OSA, what is the effect of % bone involvement on MST

Answer 13

Controversial

If >42% involvement, worse px in one study

Question 14

In dogs w OSA, there is decreased response to RT in what 2 situations?

Answer 14

Non-wt bearing at tx

On opioids

Question 15

What does RT do in OSA (cellular level)?

Answer 15

Induces apoptosis in osteoblast & osteoclasts

Question 16

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 ___

Answer 16

bone resorption…bone mineralization
osteoclasts…..pathologic bone resorption
post-translational prenylation….Ras, Rho, Ree
normal intracellular signaling…ECM…apoptosis

Question 17

Pamidronate in OSA:
% response
% pain alleviation

Answer 17

28, 40

Question 18

Pamidronate effects on:
urine NTx
rBMD

Answer 18

decrease
increases
NTx - global indication of bone resorption
rBMD - indicator of focal bone lysis

Question 19

Do DEXA scans and NTx correlate w clinical response to pamidronate in OSA?

Answer 19

DEXA does, NTx does not

Question 20

Response of OSA to Zoledronate

Answer 20

50%

100x greater antiresporptive potency than pamidronate

Question 21

In one study, dogs that received pamidronate had decreased survival…___mos vs. ___mos.
RT+ pamidronate = ___mos.
RT+ pamidronate + chemo = ____mos.

Answer 21

4 vs 8
2
7

Question 22

Samarium:
Emits what type of radiation?
Range of effect (distance)?
half-life?

Answer 22

ß emitter w a gamma photon coupled to EDTMP
2-3mm
gamma allows visualization
1.9 days

Question 23

Samarium:
Localization?
Main adverse event?

Answer 23

1. concentrates in areas of increase osteoblastic activity and binds to exposed hydroxyapatite crystals.
2. Myelosuppression

Question 24

In axial OSA of the dog, MST for DRT and PRT?

Answer 24

9 mos, 3-5 mos

Dogs treated w DRT lived sig longer than dogs treated w PRT√√√

Question 25

Is chemo beneficial in the tx of axial OSA?

Answer 25

Yes - chemo should be included in definitive tx regime

Question 26

MSTs of various OSAs:
Mandible
Maxilla
Extraskeletal
Vertebral
Rib
Skull

Answer 26

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

Question 27

Generally, OSA is most common in what part of the skeleton, what region of the bone, and FORE vs. HIND?

Answer 27

appendicular
metaphyseal
forelimb 2 x as likely as hindlimb

Question 28

Metastasis of OSA is promoted by what protein?

Answer 28

Ezrin (cytoskeltal linker protein)

Question 29

Does pathological fx presentation carry a worse prognosis in OSA?

Answer 29

No

Question 30

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?

Answer 30

Less than 15%

Greater than 90%

Question 31

What % of dogs with OSA will die ≤ 1 year w metastatic disease w amputation alone; MST of _____?

Answer 31

90%

4 mos

Question 32

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?

Answer 32

Associated w shorter DFI & survival.

Develop earlier metastasis

Question 33

What is the significance of the following markers in OSA?
Ezrin
Survivin
VEGF
COX-2 staining
IGF-2 & alcohol dehydrogenase
RON

Answer 33

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)

Question 34

In general, survival for OSA in dogs:
Chemo + amputation?
Pain meds?
surgery alone?

Answer 34

8-12 mos
1-3 mos
3-6 mos

Question 35

Is feline OSA more likely to be in forelimb or hindlimb?

Answer 35

1.6 times more likely in hindlimbs

Question 36

MSTs for feline OSA w Sx alone:
appendicular
axial
extraskeletal

Answer 36

24-49 mos
6 mos
12 mos

Question 37

Is chemo recommended for feline OSA?

Answer 37

No…10% metastatic rate