Osteosarcoma Flashcards by jared Jensen

What is the prevalence of osteosarcoma in dogs

> 8,000 dogs affected by OSA
-accounts for 85% of malignancies in skeleton
-middle age large and giant breed dogs typical
-typically middle aged to older dogs

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What kind of dogs typically get osteosarcoma

-Large and giant breeds
-Typically middle aged to older dogs

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Is osteosarcoma more common in the forelimbs or hindlimbs

forelimb > hindlimb

typically radius and humerus

“Away from the elbow and toward the knee” but can occur anywhere in skeleton

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75% on osteosarcoma occurs on the _______ skeleton while 25% occurs on the _______

75% appendicular
25% axial

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What are cancer types that occur in the bone

-Osteosarcoma
-Fibrosarcoma
-Chondrosarcoma
-Hemangiosarcoma
-Multiple myeloma
-Histiocytic sarcoma
-Lymphoma

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At the time of osteosarcoma diagnosis, what percent has pulmonary metastasis

<10% at diagnosis

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With no treatment of osteosarcoma, they what is the survival time

4-7 months

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What is the prognosis of osteosarcoma with amputation alone

> 90% will die of metastasis by 1 year with amputation alone

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How is osteosarcoma spread

Hematogenously

lung > bone > soft tissue

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What are the clinical signs of osteosarcoma

1) lameness and mass on limb
2) +/- trauma/ acute onset
3) Palpable mass on rib or flat bone -“bony”
4) Dysphagia (lower jaw)
5) exophthalmus (zygomatic arch) , facial deformity, paresis / paralysis

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T/F: osteosarcomas commonly can cross the joint

False - they tend to not cross the joint

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What are your differential diagnosis for osteosarcoma

Osteomyelitis
Metastatic tumor
Other primary bone tumors

all look the same- use biopsy or changes over time

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What are often the first diagnostic test for osteosarcoma

Limb radiographs - not sensitive for early detection of aggressive bony lesions

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How much cortical bone is lost before visible on radiogrpahs? **

40% - this is why radiographs are not an early detection tool

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You are presented with 8yo mix breed dog having a 1month hx of L forelimb weight bearing lamness. On PE pain is localized to distal radius. What do you do

Prescribe NSAIDs and reevaluate in 2 weeks

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What are the radiographic findings of osteosarcoma

1) Cortical lysis (a minimum)
2) Metaphysis
3) Lytic or blastic
4) Sunburst pattern
5) Codman’s triangle
6) Doesnt cross the joint

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When you suspect osteosarcoma, what can you do to diagnose

Fine needle aspirate with ALP stain (tells sarcoma or carcinoma)

Biopsy- be careful not to contaminate uninvolved tissues

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What do you do after finding radiographic evidence of an aggressive bone tumor

many different answers
1) recommend limb amputation
2) perform additional staging
3) fine needle aspirate
4) do incisional bone biopsy
5) recommend euthanasia

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What can you do to tell where osteosarcoma is

1) Thorough health assessment
2) 3-view thoracic radiographs (thoracic CT is more sensitive)
3) Orthopedic exam
4) Bone scan or PET CT
5) Abdominal ultrasound

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What is whole body PET CT

a high sensitive test that looks for highly active tissues
able to detect bone metastasis and soft tissue metastasis

Scintigraphy fused with a CT scan - pulmonary CT

Has different isotypes (18F FDG)
learning curve
Replaced nuclear bone scans

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Is prognosis better with osteosarcoma of appendicular or axial skeleton

appendicular

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How can you tell the extent of osteosarcoma disease

Radiographs
Nuclear scans
CT/MRI

can surgery remove all local disease?

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When is bone biopsy considered

highly encouraged in limb salvage candidates
prevents over-extensive or inappropriate treatments

diagnosis may change the owner’s willingness to treat

if its not the typical place

we dont biopsy as much due to fine needle aspirates

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What is important to do when taking a bone biopsy

-treat tumor like an infectious focus
-do not contaminate uninvolved tissues
-small removable biopsy tracts (ideally done by the surgeon who will ultimately perform the limb salvage)
-cranial or craniolateral incision parallel to the long axis of the limb

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What are methods of bone biopsy

1) Open -Wedge -Trephine -+/- Currette 2) Closed -Jamshidi

Why might you get non-diagnostic bone biopsy (not uncommon)

1) Reactive bone -samples obtained from periphery of lesion 2) Other primary tumor -small sample

uses multiple therapies to achieve the longest survival with the best possible quality of life

curative-intent therapy (death is more common due to metastatic disease)

therapy that accepts the progression of disease therapy is aimed at alleviating signs only

palliative-intent therapy (death more commonly due to local disease)

with palliative-intent therapy, death is more commonly due to

local disease this therapy accepts the progression of the disease and therapy is aimed at alleviating signs only

With curative-intent therapy, death is more commonly due to

metastatic disease

What are the prognostic factors of osteosarcoma

-Serum ALP elevation (might be from bone but might be from something else)- different isotypes not told -Tumor stage (Large tumor volume and presence of metastasis) -Histologic grade -Location -Age (younger dogs have shorter DFI) -Monocyte, lymphocyte counts? -Emerging molecular markers

What treatment method is challenging with osteosarcoma

Radiation therapy

What is the prognosis of osteosarcoma 1) Palliative 2) Amputation alone 3) Amputation (or limb salvage or SRT) and chemotherapy

Palliative :1-2 months or greater Amputation alone: 4-7 months Amputation (or limb salvage) and chemotherapy: 10-16 months (1 year MST)

What are the treatment options for osteosarcoma for curative-intent

Surgical options 1) Amputation + chemo 2) Limb salvage + chemo (multiple limb salvage options) Radiation Option 1) Sterotactic Radiation Therapy + chemo (is a limb salvage option)

What is the indication of amputation for curative intent for osteosarcoma **

Limb is removed 1) Removes the source of pain 2) Wide excisional margins 3) Few complications 4) Does not require specialized skills or facilities classical surgical treatment

What are the contraindications to amputation for osteosarcoma *

1) Progressive neurologic disease 2) Prior amputation of another limb 3) Severe orthopedic conditions -advanced DJD is not a contraindication is most cares 4) Owner will not permit

T/F: advanced DJD is a contraindication of amputation for osteosarcoma

False - not in most cases

T/F: large dogs do poorly with amputation

False - it is the exceptions, not the rule large dogs require slightly more maintenance until fully recovered -towel sling on slippery floors -elevated food dishes

How is limb salvage for curative intent different form amputation *

1) small margins 2) Higher risk of local recurrence 3) Higher complication rate 4) More difficult technique 5) Salvages the limb

How is limb salvage similar to amputation

1) Similar survival time 2) Remove source of pain for curative intent

What osteosarcoma location is best candidate for traditional limb salvage surgery ******

distal radius ***** ulna scapula

What makes a good candidate for traditional limb salvage surgery *

1) disease confined to leg 2) histologically confirmed tumor 3) tumor affects <50% of bone length 4) Good general health 5) No pathological fracture 6) Distal radius

What are the unfavorable locations for limb salvage surgery *

Stifle Tibia Humerus higher complication rate

What is allograft limb salvage

tumor is completely excised fresh frozen allograft sized and shape secured with large bone plate creates carpal arthrodesis

What are the recommended surgical margins for resection of the osteosarcoma tumor in traditional limb salvage surgery

3cm bone margins and 1 fascial plane (same as soft tissue sarcoma) will often still do it despite not having margins

What are the outcomes of traditional limb salvage surgery

1) 75% fair to good use of limb 2) 15% local recurrence 3) 40-60% infection 4) 25-40% construct failure equivalent or better survival than amputations

Infection after traditional limb salvage surgery is

associated with improved survival bc immune system is stimulated however rarely can be eradicated can have a negative effect on quality of life

a limb salvage proceudre that is based on the principles of distraction osteogenesis where induction of new bone formation between bone surfaces that are gradually pulled part

Bone transport osteogenesis -takes a very long time

What radiation therapy option is another limb salvage option for osteosarcoma

Stereotactic radiation therapy -Requires planning CT 50% alive 1 year

What serves as a radiosensitizer for stereotactic radiation therapy for osteosarcoma

Carboplatin

What are the complications of stereotactic radiation therapy

Fracture Infection Ulceration

What is the role of radiation therapy after limb amputation in the treatment of appendicular OSA ***

It is not indicated as amputation is a wide local or radical excision

Regardless of surgery performed, dogs with OSA need ________ to extend survival

chemotherapy

What chemotherpy agent is used in dogs with OSA *

Carboplatin 4-6 doses once ever 3 weeks

How do you followup dogs with OSA

Restage q 2-3 months -Thoracic rads +/- abdominal US orthopedic examination limb radiographs if implants +/- PET CT

What do dogs most typically die of when receiving palliative care for an appendicular osteosarcoma **

Euthanasia as a resuslt of a local tumor (such as increasing tumor pain or pathologic fracture)

where you accept the progression of the disease therapy aimed at alleviating signs only therapy should be multimodal

Palliative therapy

What can you do as palliative therapy for OSA

1) Palliative radiation therapy (lower dose than curative) 1-3 fractions are typical (dictated by patient comfort) Less expensive very effective at managing pain (1-4 months relief for 75% of patients) 2) Multimodal analgesia 3) Pamidronate / zolendronate / bisphosphonate therapy

Is radiation therapy dose higher with palliative or curative therapy

Curative intent

What procedure has been shown effective for treatment of hypertrophic secondary to pulmonary OSA metastasis

Metastectomy - to remove the solitary lesion if you cant then maybe do bisphosphonate

What drug can you use in palliative care for OSA that makes it hard for the osteoclast to degrade the bone

Bisphosphonate therapy

pain management for amputation

pre-emptive: opioids, epidurals, NSAIDS, intraoperative nerve blocks after: opiod CRI addition of ketamine, lidocaine, dexmedetomidine or NSAIDs local anesthestics- maybe Nocita physical therapy at home

Osteosarcoma Flashcards

(62 cards)