Approach to cancer in small animals

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Approach to cancer in small animals
2015-04-17 15:56:16

Vet Med - Module 12
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  1. List the different presentations of cancer
    • Superficial lump/mass
    • Ulcerated/inflammatory
    • May be large and obvious
    • May present as non-specific clinical signs as a direct effect of internal tumour e.g. vomiting, diarrhoea, weight loss/wasting
    • May present with haematological abnormalities
    • May present with neoplastic syndrome
  2. What are the three steps when making a diagnosis?
    • Take a thorough history
    • Take a biopsy for histopathology
    • Take a fine needle aspirate for cytology
  3. Give examples of questions you would ask during your history
    • Age/sex/breed of animal
    • Trauma/injury?
    • When was it first noticed?
    • Rate of growth?
    • Previous lumps or bumps?
  4. What does a biopsy give us information about?
    Tissue architecture and tumour grading
  5. What are the advantages/disadvantages of biopsy?
    • A - most accurate and definitive diagnosis
    • D - expensive, time consuming, requires local/sedation or GA
  6. What is tumour grading?
    Assessment of the degree of malignancy as determined by a pathologist
  7. What is the criteria for tumour grading?
    • Cellular differentiation, pleomorphism
    • Mitotic index
    • Invasiveness
    • Amount of necrosis
    • Overall cellularity
    • Stomal/inflammatory reaction
  8. What are the tumour grades for a) sarcomas b) mast cell tumours?
    • a) High grade - needs aggressive treatment and chemotherapy, low grade - local surgery usually sufficient, intermediate grade - local treatment +/- chemotherapy
    • b) high grade - needs aggressive treatment and chemotherapy, low grade - local surgery usually sufficient
  9. How much tissue should you biopsy?
    As much as possible within reason
  10. What type of tissue should you take for a biopsy?
    Choose a representative area - avoid inflamed, necrotic, ulcerated tissue.  Include a margin of the lesion and some normal tissue if possible.
  11. What are the different types of biopsy?
    • Incisional (wedge)
    • Excisional (whole mass)
    • Surface grab
    • Needle core
    • Punch
  12. What are the advantages/disadvantages of fine needle aspirate?
    • A - quick, easy, cheap, no GA
    • D - can be unrepresentative, does not provide information about tissue architecture
  13. What are the steps involved in fine needle aspirate?
    Suck out cells from mass, expel onto glass slide, smear the aspirate, stain and examine under microscope
  14. What are some other methods for cell collection for cytology?
    • Ultrasound guided aspirates
    • Bone marrow aspirates
    • Impression smears
    • Cytospins of washes/lavages
    • Scrapings
  15. What is tumour staging?
    Defining the anatomical extent of the tumour in terms of primary site and distant spread determined by a clinician
  16. At what concentration of cells is a tumour first palpable?
  17. Why do we do tumour staging?
    To decide whether treatment/what treatment is feasible
  18. What system is used for tumour staging?
    TNM system
  19. What does T stand for?
    Primary tumour
  20. What do we asses in the primary tumour?
    • Measure its dimensions with a ruler or callipers¬†
    • Assess whether there is local invasion
    • Are there multiple primary lesions
    • Use imaging to assess internal masses
  21. What does N stand for?
    Local lymph nodes
  22. What do we asses in the local lymph nodes?
    • Palpate them - are they hard? fixed? enlarged?
    • Image
    • Aspirate
    • Biopsy/examine
  23. What does M stand for?
    Distant metastases
  24. What are the four ways metastases can spread?
    • Lymphatics (carcinomas, MCT)
    • Haematogenous (sarcomas)
    • Direct extension along tissue planes
    • Seeding across thoracic/peritoneal cavity
  25. What do we asses in the distant metastases?
    • Physical examination¬†
    • Imaging
    • Laboratory evaulation - organ function
    • FNA/biopsy to confirm suspicions