Lecture 4 (continued): Bone Tumors

Question 1

What are primary bone tumors??

Answer 1

neoplastic cells which arise from cells located in bone tissue

Question 2

What percent of all canine neoplasias are primary bone tumors?

Answer 2

5 %

Question 3

What is the most common priamry bone tumor of canines?

Answer 3

> 80% are osteosarcomas

Question 4

Osteosarcomas most often arise from ______

Answer 4

mesynchymal bone cells

Question 5

Where so the majority of osteosarcomas originate?

Answer 5

the appendicular skeleton

Question 6

What bones have a predilection for osteosarcoma?

Answer 6

metaphyseal, monostotic-one bone, away from elbow, towards knee

Question 7

At the time of diagnosis what percent of cases can metastasis be diagnosed on thoracic rads? What percent have micrometastasis?

Answer 7

5% detectable on rads

~90% have micro

Question 8

Over the long term __% of dogs with osteosarcoma develop thoracic metastasis

Answer 8

> 60% of dogs

Question 9

What are teh other 2 common bone tumors?

Answer 9

chondrosarcoma- flat bones, axial skeleton, malignant but slow to met, non responsive to chemo

fibrosarcoma- axial skeleton, slow to met, excision can be curative

Question 10

Osteosarcoma has what kind of distribution?

Answer 10

bimodal, young dogs 1-2 years old dogs 10-12

more common in males than females

Question 11

What are you looking for on rads with regards to bone tumor evaluation?

Answer 11

loss of tabecular pattern in metaphysis

punctate lysis

primary tumors DO NOT cross the joint

Question 12

_____ are important for staging tumors and significance of dz

Answer 12

Thoracic rads

Question 13

Where do you want to obtain your bone biopsy sample from?

Answer 13

radiographic center of the lesion

multiple samples

take rads after biopsy to confirm biosy

Question 14

What are the two Tx paradigms for bone tumors

Answer 14

Palliative- aim to provide support

curative intent- aim to remove all tumor cells from body, local excision and chemotherapy

Question 15

What are the Tx options for primary bone tumors?

Answer 15

tumor-excision-amputation or limb spare surgery

tumor excision with chemotherapy

palliative radiation

palliative analgesia

euthanasia

Question 16

What should be submitted in a histopathology sample?

Answer 16

submit the whole sample, include regional lymph nodes if possible include a complete history

Question 17

What is limb spare surgery?

Answer 17

remove bone tumor , keep leg, augment limb allograft, arthrodesis, endoprothesis

doesnt improve survival time

Question 18

What are the 2 benefits of chemotherapy?

Answer 18

Tx micrometastasis

Chemotherapy prolongs survival time

Question 19

T/F

The benefits of palliative radiation include diminished bone pain, increased median survival time, but it may increase the risk of pathological fracture, if they are feeling better and become more active

Answer 19

FALSE

It does help bone pain,

It does NOT increase median survival time because it does not affect metastasis bc it doesn’t attack the mets

It does increase the risk

Question 20

What is the median survival times for OSA is dogs with palliative tx? Curative intent?

Answer 20

Palliative- 3-5 months

Curative- 10-14 months

Question 21

What % of bone tumors in cats are OSA?

Answer 21

70%, met potential is 14% more common in pelvic limb

Question 22

What is the mean age of cats with OSA and what is their median survival?

Answer 22

10.2- older cats

Median survival is 24 months