Musculoskeletal & Integumentary tumors (sarcoma): slides 3, 15, 16, 18, 37, 40 - 43. Flashcards
What type of tumor??
Diverse group of tumors accounting for 15% (dogs) & 7% (cats) of cutaneous & SQ tumors
– 1% of all malignancies
Soft tissue Sarcoma
Over 20 different histologic subtypes of STS but are considered as a collective group because why?
similar biologic behaviour and histologic features
Behavior is characterized by?
a propensity for local invasiveness w/ a low to-moderate risk of metastasis (grade dependent)
Most STS are _____ and present in ______age dogs and cats?
Most are solitary and present in middle-aged to older dogs & cats
What is the specific breed and sex predilection for STS?
No specific breed or sex predilection
large breed dogs in general may be overrepresented for STS development
What is the age predilection for STS?
No general age predilection except for rhabdomyosarcoma variant which tends to develop in younger dogs
Describe the capsule and margins of STS and if it’s infiltrative or not?
• Pseudo-encapsulated soft-to firm masses w/ poorly defined margins
– Infiltrative into surrounding tissue
Is recurrence common?
Local recurrence after
conservative excision is common
– exemptions
What route of metastasis?
Hematogenous route of metastasis (generally < 20%)
Is regional LN metastasis uncommon or common?
• Regional LN metastasis
uncommon
- Synovial cell exemption*
Grade predictive of metastasis and resected margins predictive of _______ ______
local recurrence
– 1, 2, 3 —> 10, 20, 30 RULE
Measurable/bulky tumors (>___cm)
tend not to respond to
chemotherapy or RT; >5 cm
For tumor assessment what can you do to rule out DDX of lipoma, seroma, inflammation & abscess
FNA
If a sarcoma is confirmed then you need to ask yourself?
how important is knowledge of the GRADE for me to develop a therapeutic strategy?
What are some things to consider with STS with local tumor assessment?
Location of the tumor, size & invasiveness, owner’s position (would they do multiple surgeries for curative intent, are they up for adjunctive RT) and patient characteristics (age/comorbidities)
If grade information is required what can you obtain?
Incisional biopsy (tru-cut vs. wedge not usually punch since they are often hypodermal)
What do we need todo for pulmonary metastasis?
Thoracic radiographs
Is abdominal U/S for presurgical staging needed?
– Abdominal u/s for presurgical staging is generally not indicated for most STS’s
What kind of excisions should be considered when performing surgery?
Wide excision (3cm radial & 1 fascial plane or 2 muscle planes deep)
– All biopsy tracts and areas of fixation (including bone/fascia/tendon) are removed en bloc
With STS radical surgery such as ______ may be required
(amputation/pelvectomy)
What is indicative about the first surgery for STS?
Remember the 1st surgery provides the best change for local control and cure
Incompletely resected tumors increase….?
increase patient morbidity, tx $$, increases risk of further local recurrences and decrease survival
– So plan thoroughly and execute properly
What is unique about the prognosis of STS?
Px is usually determined by local disease control rather than distant metastasis
What are the 3 main negative prognostic indicators for local control?
– Large tumor size
– Incomplete sx margins
– High histologic tumor grade = Higher met. Rate and more invasive locally
Global recurrence rate of STS following incomplete resection = 28%, recurrent STS is more difficult than?
recurrent STS = More difficult to control than primary tumors w/ shorter DFI ±
increased metastatic rate
What is the metastatic rate for grade 1 grade 2 and grade 3
10% (Gr I), 20% (Gr II), 30 – 50% (Gr III)
What is the MST with surgery alone?
MST = 1,416 d (~4 y) w/ sx alone (do worse w/ aggressive variants)
Circa late 1980’s – Pennsylvania law established that all cats must be?
rabies vaccinated
Simultaneous changes to 2 vaccines developed around same time: what are the 2 vaccines?
Pathologists at UPENN then started seeing increased incidence of these 2 things?
– Killed RV & FeLV vaccines for SQ admin. developed
increased incidence of reactions and formation of tumors at vaccination sites
When path at upenn started seeing increased incidence of rxns and formation of tumors at the injection site, it was suspected that _____ adjuvant in vaccine was contributing to massive inflammatory rxn. that leads to?
aluminum
leads to uncontrolled fibroblast and myofibroblast proliferation and eventual tumor formation
Incidence of the development of sarcomas at site of rabies or FeLV
vaccination site: is?
1/1,000 to 1/10,000
Time to tumor development for feline injection site sarcomas post vaccination is?
4 weeks – 10 YEARS
What is unique about feline injection site sarcomas compared to typical soft tissue sarcomas?
These sarcomas are histologically and biologically more aggressive than typical STS’s!
What did the studies conclude on feline injection site sarcoma?
Based on studies it is still unclear if non-adjuvanted vaccines are any
safer
– Renamed syndrome from vaccine associated sarcoma to ISS b/c other etiologies implicated (interferon injection/microchip)
Feline ISS
What is reasonable todo to give you a sarcoma dx? Ideally would like to confirm…..?
Cytology very reasonable to do
– Ideally like to confirm ISS vs. typical STS to justify higher surgical dosing which requires INCISIONAL biopsy
With Feline ISS, please DON’T do an ______ _______
excisional biopsy!
With Feline ISS
-Accurate pretreatment knowledge of the extent of disease is important:
- Tumors are very _______
- ____ may be performed for surgical margin planning
– Tumors very infiltrative
– CT may be performed for surgical margin planning
What is the current treatment recommended for Feline ISS? What do you include? What is the recurrence rate? What is the preferred technique for establishing local control?
Current recommendation is surgical excision w/ 5cm radial margins and 2 muscle planes deep
– Including body wall, soft-tissue or bone (i.e. dorsal scapula/spinous processes or limb)
– Recurrence rate = 14%
– Complication rate = 11% w/ 8% sustaining dehiscence of the incision
- Historically reported rates of local recurrence for feline ISS after treatment range from 26% to 59%
- Validates surgical model (i.e. 5 cm margins) as the preferred technique for establishing local control of feline ISS’s
