Tumors of appendicular and axial skeleton

Question 1

What is the most common primary bone tumor

Answer 1

Osteosarcoma

Question 2

OSA signalment

Answer 2

Large-Giant breeds
Neutering status!
Bimodal distribution 1-2yr & 7-9yrs
Small dogs - axial skeleton

Question 3

What is the OSA neutering status factor

Answer 3

2x risk of OSA in gonadectomized dogs
ROTTIES
intact = protective factor

Question 4

Proposed OSA etiologies

Answer 4

Hormones (neutering)
Genetic - rotties, greyhound, danes, s bernard, irish wolfhound
repetitive microtraumas
molecular factors

Question 5

What are some molecular facotrs

Answer 5

Overexpressed oncogenes: MET, TrK, HER-2
Abbreant IFG-1
Abberant mTOR signaling
Telomeralse presence

Question 6

OSA presenting complaint

Answer 6

lameness - inflammation, micro fractures

Swelling - extra compartmental extension of tumor

Question 7

OSA differntials

Answer 7

Chondrosarcomas

Infectious - fungal will have systemic disease

Question 8

Anatomic locations

Answer 8

Away form elbow, towards knee
80% in appendicular skelton
forelimbs 2x > hindlimb
*distal radius!
Metaphyseal region

Question 9

OSA dx: CBC / chem

Answer 9

elevated ALP = bad

Question 10

OSA dx: locoregion lnn assessment

Answer 10

5% incidence = low

Question 11

OSA dx: thoracic met check vs CT

Answer 11

90% have micromets at Dx. missed with rads

Question 12

OSA dx: FNA/Cytology

Answer 12

85% diagnostic accuracy - preferred over biopsy

Question 13

OSA dx: Biopsy (2)

Answer 13

Jam shedi - worse dx, better px

Michele trephine - better dx, worse px (fractures)

Question 14

OSA dx: Radiographic appreance

Answer 14

Aggressive bone lesions
lytic, plastic, mixed
codmans triangle
palisading cortical bone
fractures
DONT CROSS JOINTS

Question 15

Codmans triangle

Answer 15

periosteal lifting caused by subperiosteal hemorrhage

Question 16

Local control

Answer 16

Amputation = gold standard
Limb salvage
Stereotactic radiosurgery

Question 17

Amputation techniques

Answer 17

forelimb - forequarter technique (include scapula)

Hindlimb - coxofemoral disarticulation technique/ en bloc acetabulectomy/subtotal hemipelvectomy

Question 18

Amputation results

Answer 18

well tolerated.
thoracic - harder balance
pelvic - harder gaining speed

Question 19

Limb salvage indications

Answer 19

severe OA
neurological disease
Morbid obesity
OWNER
*distal radius

Question 20

Limb salvage contraindications

Answer 20

large lesion
extensive soft tissue involvement
pathology fracture
inappropriate location
noncompliant owner
advanced disease

Question 21

Limb salvage locations

Answer 21

distal radius
digit/metacarpus/tarsus
distal ulna
scapula

Question 22

distal radius salvage

Answer 22

preferred/most common

reconstruct w. surgical steel

Question 23

Distal ulna salavage

Answer 23

ulnectomy.
excision of styloid process
annular ligament reinforcement

Question 24

Limb salvage complications

Answer 24

> 50% have complications
implant failure 40%
local reoccurrence
infection >50%, 2/3 dx after 6 months

Question 25

Limb salvage prognosis

Answer 25

good-excellent function 80%

Question 26

Why is infection helpful in limb salvage

Answer 26

it increases the MST and met free interval y activating the immune system to be hyperactive

Question 27

Stereotactic radiosurgery

Answer 27

entire radiation dose delivered in one treatment min dose = 35Gy high dose =50-60Gy proximal humerus is best

Question 28

Systemic therapeutics

Answer 28

Adjunct chemo

Question 29

Adjunct chemo options

Answer 29

Carboplatin (DOC) Bisphostphates Amino-bisphosphates

Question 30

carboplatin

Answer 30

monitor CBC | Starting pre, during, post op doesn't alter efficacy

Question 31

Bisphosphates

Answer 31

inhibits osteoclastic bone resolution

Question 32

Amino-bisphosphates

Answer 32

Pamidronate | pain palliation 30-50%

Question 33

Palliative therapeutics

Answer 33

RT | Analgesia

Question 34

RT

Answer 34

50-92% response rate. but very short duration of response better response when <50% bone involved and proximal humerus

Question 35

Analgesia

Answer 35

every patient should get. | NSAIDs, opioids, NMDA antagonists, anticonvulsants

Question 36

Aratana

Answer 36

canine OSA vaccine indevelopment attenuated listeria monocytogenes

Question 37

PROGNOSIS (KNOW THIS)

Answer 37

palliative analgesia- 1-3m Surgery - 4-6m Sx + chemo - 8-12m Chemo alone - not recommended

Question 38

Prognostic considerations

Answer 38

``` Body weight age site volume histologic grade ALP ```

Question 39

Weight

Answer 39

<40kg is positive

Question 40

Age

Answer 40

<7yrs and > 10 is positive

Question 41

Site

Answer 41

proximal humerus is negative

Question 42

Volume

Answer 42

larger is negative

Question 43

Histological grade

Answer 43

3 is negative

Question 44

ALP

Answer 44

NEGATIVE preop increase that doesn't decrease within 40 d every 100U/L increase is 25% risk of death

Question 45

Feline OSA

Answer 45

diaphysis Pelvic > thoracic less aggressive, slower growth amputation may be curative