Canine Lymphoma Flashcards

1
Q

How are lymphomas classified? (4)

A
  • based on anatomic form e.g. gastrointestinal, mediastinal, cutaneous
  • cytologic/ histologic criteria
  • immunophenotype (b cell or t cell)
  • high grade vs low grade
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2
Q

Which lymphoma is the most common?

A

Multicentric (multiple origins)

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3
Q

Why do high grade lymphomas generally respond better to chemotherapy than low grade lymphomas?

A

because chemo targets rapidly dividing cells which is what high grade lymphomas are made up of (large lymphocytes= immature= rapidly dividing)
BUT low grade lymphomas still have a better prognosis

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4
Q

What is the major presenting sign for lymphoma?

A

Peripheral lymph node enlargement e.g. submandibular, prescapular, popliteal with possible hepatosplenomegaly

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5
Q

Why does a lymphoma often cause Polyuria/ Polydipsia?

A

Lymphoma releases parathyroid releasing hormone which causes hypercalcaemia

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6
Q

Which lymphoma (B or T cell) tends to be the most aggressive?

A

T cell

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7
Q

What do we mean by ‘Minimum Database’?

A

Acquired from patient to get a general idea into their health- this includes haematology (including blood smear), biochemistry and urinalysis

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8
Q

What will provide a definitive diagnosis for haematopoietic neoplasia and what will this look like?

A

Fine needle aspirate cytology of the lymph node or mass
Should see, very few small lymphocytes and a monotonous population of large lymphocytes and possibly some mitotic figures

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9
Q

What lymph nodes should we avoid taking cytology from and why?

A

Submandibular lymph nodes- they’re very reactive and so can distort figures/ samples

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10
Q

If the initial cytology/ FNA isn’t diagnostic what is our next option?

A

Biopsy of the lymph node (popliteal is the easiest to do)

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11
Q

What is the benefit of performing an immunohistochemistry of a tissue sample?

A

allows immunophenotyping- can see if its a b cell or t cell tumour

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12
Q

How does immunocytochemistry differ from immunohistochemistry?

A

allows immunophenotyping from the cytology slides (so less invasive)

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13
Q

What is PARR and how does it work?

A

PCR for Antigen Receptor Rearrangements
Uses PCR to evaluate lymphocyte receptor gene length to assess clonality levels

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14
Q

When is it useful to use PARR as oppose to cytology?

A

Useful when cytology cannot determine neoplastic vs reactive population

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15
Q

In PARR, a polyclonal result suggests….
What about a monoclonal result…

A

polyclonal= reactive
monoclonal= lymphoma

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16
Q

How does MHC expression affect prognosis?

A

Low MHC II expression in a B cell lymphoma is a negative prognostic factor

17
Q

Briefly describe the initial diagnostic approach in a patient with a suspected Haematopoietic Neoplasia?

A

Minimum database (CBC, Biochemistry, Urinalysis)
Diagnosis with FNA cytology of peripheral lymph nodes or mass
Immunophenotyping using flow cytometry

18
Q

What stage lymphoma is the most common?

A

3 (generalised lymph involvement)

19
Q

What do we mean by substages for lymphoma?

A

Lymphoma is categorised 1-5 based on metastasis but can be further classified based on clinical signs e.g.
a- without systemic signs
b- with systemic signs

20
Q

How do we stage a lymphoma?

A

Imaging- thoracic radiographs, abdominal ultrasound, CT scan
Sampling/ FNA- liver and spleen

21
Q

Can we sample bone marrow to help stage the lymphoma?

A

You can BUT its invasive, costly and will only indicate stage 5 lymphomas of which the prognosis remains unchanged from grade 4 (so is there any point?)
Only indicated if there’s cytopenia’s or lymphocytosis

22
Q

Does staging alter the treatment plan?

A

Only if there’s Renal, CNS or bone marrow involvement (need drugs that penetrate these better)

23
Q

What is the treatment of choice for lymphoma?
Is that applicable to all?

A

Maximum tolerated dose multi agent chemotherapy
[can do surgery for solitary lesions or radiation therapy for nasal/ oral lymphomas]

24
Q

We can give Prednisolone as palliative care and as pre treatment prior to Chemotherapy- what do we need to be aware of if we do this?

A

The length of the prednisolone pre treatment can upregulate chemotherapy resistance mechanisms in the neoplastic lymphocytes

25
Q

What protocol is used to treat a B Cell lymphoma?

A

CHOP
[Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone]

26
Q

A B cell lymphoma is treated using the CHOP protocol but it relapses more than 3 months later- what now?
What about if it relapses less than 3 months later?

A

> 3 months - repeat CHOP
If less than 3 months- use a rescue protocol such as Single agent lomustine, Rabacfosadine etc.

27
Q

What protocol is used to treat T Cell Lymphomas?

A

LOPP
[Lomustine, Vincristine, Procarbizine, Prednisolone]

28
Q

If there is CNS/ Bone marrow lymphoma involvement, what agent do we give to treat?

A

Cytarabine inclusion

29
Q

If the patient has a cutaneous lymphoma, what is the best treatment?

A

Single agent Lomustine

30
Q

When is chemotherapy safe to administer to the patient?
[think cell counts]

A

When neutrophils are > 2.0 K/uL
platelets > 100 K/uL

31
Q

Lomustine can cause hepatotoxicity, what can we do to reduce this risk?

A

Monitor ALT and administer Denamarin to reduce the risk

32
Q

Cyclophosphamide (first stage of CHOPP) carries the risk of haemorrhagic cystitis- how can we mitigate this risk?

A

Furosemide co-administration reduces the risk

Risk is more common when it is administered metronomically (lower doses for longer) so don’t do that lol

33
Q

What are negative prognostic factors for canine lymphomas? (4)

A

T cell immunophenotype
Substage b
Prolonged pre treatment with steroids
Stage 4 &5 (some studies)