FISS

Question 1

What is the typical signalment of an FISS?

Answer 1

 4 weeks to 10 years after injection
 Median age 8 years
 No breed or sex predisposition
 Localization

Question 2

What are some possible risk factors for FISS?

Answer 2

Adjuvant or non adjuvant? Alluminum?
Needle, syringe, multidose, mix vaccines in same syringe or vial, supplier, temperature or vaccine?
Less inflammation, less risk?

Question 3

Outline the aetiopathogenesis of an FISS

Answer 3

 Increased expression of growth factors PDGF, EGF, FGF-β, TGF-α
Proliferation
Neoplastic transformation & Neoangiogenesis
 Oncogenes, oncosuppressors, transcription factors
C-jun, p53, c-KIT, mdm-2, STAT-3

GENETIC PREDISPOSITION + INFLAMMATION

Question 4

What do you see on histopathology?

Answer 4

Subcutaneous (or muscle) and invasion of fascial planes
Mesenchymal tumours of several histotypes
FSA (++), OSA, CSA, RabdomyoS, MFH
 Criteria of malignancy: nuclear and cellular
pleomorphism, necrosis, mitotic index (60% grade III)
Peripheral inflammatory infiltrate of lymphocytes and
macrophages
Transitional areas between inflammation and tumour

Question 5

What is the 3-2-1 guidelines for injection site reactions?

Answer 5

• present after 3 months
• bigger than 2 cm
• growing after 1 month

Then
Incisional biopsy - not excisional biopsy or cytology
If granuloma - remove if still present after another month
If neoplasia deal with appropriately

Question 6

If you have an FISS, what further diagnostics should be done?

Answer 6

 Haematology, serum biochemistry, urinalysis
 FeLV FIV
 Chest radiographs +/- abdominal ultrasound
 Regional CT +/- chest Volume CT 2x macro!

Question 7

What are the key aims of therapy?

Answer 7

3-5 cm of margins
Reconstruction of abdominal wall
Osteotomy
• Histopathology
• Assess margins

Question 8

What factors are associated with decreased survival/ recurrence time?

Answer 8

Nodulectomy < Surgery with wide margins
(79 days) or radical (325-419 days)
Non specialist surgeon < Specialist surgeon
(66 days) (274 days)
Number of surgeries

Question 9

What are the pros and cons of 3cm 1 facial plane v 5cm 2 facial plane excisions?

Answer 9

> 3 cm, one deep fascial plane
Complete resection < 50%
Without recurrence at 1 year (35%) and 2 years (9%)
Without recurrence for 12-16 months FISS extremities

> 5 cm, two deep fascial planes
Complete resection 97%, Recurrence 11%
Without recurrence at 1 (91%), 2 (86%), 3 (74%) years
Wound dehiscence risks

Question 10

Which radical surgeries may be needed depending on the location of the tumour?

Answer 10

 Tumours in interscapular region:
Osteotomy of spinous processes
and/or Scapulectomy
Dorsal spinous processes & Dorsal aspect of scapula
 Tumours on the trunk:
Surgical excision of thoracic or Abdominal wall
 Tumours on extremities:
Limb amputation and/or hemipelvectomy

Question 11

What are the pros and cons of radiotherapy prior to surgery?

Answer 11

Fewer hypoxic cells so high antitumoral effect
Reduction of tumour size pre surgery = Decreased
surgical contamination
Increased risk of surgical complications

Question 12

What are the pros and cons of radiotherapy post surgery?

Answer 12

Microscopic residual tumour = increased efficacy Immediate after surgery
Increased size of irradiation field
Increased number of hypoxic cells
Risk of tumour cell repopulation

Question 13

Outline the use of streotactic radiation therapy

Answer 13

 High doses of radiation in a limited number of treatment sessions (1 to 5)
Radiosurgery if single treatment
 Reserved for well delineated bulky tumours - a precision technique
 Relies on accuracy of treatment to intended target
 Palliative intent but:
-higher dose of single fraction than palliative
-lower total dose than curative intent
-different modality of delivery (daily or every 48 hours vs weekly) - increased intensity & efficacy

Indications:
1. Tumors deemed unlikely to be effectively surgically
cytoreduced by a veterinary surgical oncologist
2. Recurrent disease after prior surgery (with or without
adjuvant radio- or chemotherapy)
3. Palliative purposes – if client declines standard definitive treatment options

Question 14

What are the typical drugs used for chemo?

Answer 14

 Doxorubicin, vincristine, cyclophosphamide,

carboplatin, mitoxantron, paclitaxel

Question 15

Outline the use of oncept IL-2

Answer 15

• Feline interleukin-2 recombinant canarypox virus
• 1 dose of 1 ml split in 5 Subcutaneous Injections of
  approximately 0.2 ml at each corner and at center of
  5x5 cm square centered on the middle of the surgical scar
• Indications: Cats with non metastatic fibrosarcomas of 2 to 5 cm as adjuvant to surgery and radiotherapy
  Efficacy only tested in conjunction with surgery and
  radiotherapy
• May see transient pain/ apathy/ pyrexia

Question 16

Outline the science behind tyrosine kinase inhibitors

Answer 16

PDGF e PDFR play a role in the growth of FISS cells
Imatinib, masitinib, toceranib
Imatinib mesylate inhibits platelet-derived growth factor
activity and increases chemosensitivity in feline vaccineassociated sarcoma.
masitinib is highly selective for PDGF
Masitinib demonstrated in vitro anti-proliferative &
Pro-apoptotic activity in primary & metastatic FISS cells

Question 17

How can you minimise the risk of FISS?

Answer 17

Vaccinate only cats at risk (young vs adults, exclusively indoor cats) - FeLV?
NO interscapulare region, intramuscolar, adjuvant
Standardize and register all vaccinations (site, product,
supplier, production number)
Do not mix vaccines and report reactions

Question 18

Outline ocular trauma associated sarcomas in cats

Answer 18

 Risk of developing ocular sarcoma in Globes of cats
previously subjected to trauma of penetrating nature,
particularly with lenticular destruction - release of
lenticular substances - low-grade inflammation
 Infiltration of optic nerve -chiasma & brain
blindness & neurological signs
 Latency often several years
 Fibrosarcoma (FSA) most common ocular sarcoma
(8/13)
 Osteoid deposition in 3/8 FSA – also a feature of
severely traumatised globes
 Enucleation may prolong survival

Question 19

With prompt therapy, what is the typical px for FISS?

Answer 19

 Free of disease 13-19 months
 Median survival 23 months
 15-24% metastasis