Feline lymphoma, leukaemia + myeloma Flashcards
What are Pre FeLV lymphoma?
- Mediastinal/multicentric lymphoma in young/adult cats
What is post FeLV lymphoma?
- Gastrointestinal lymphoma in geriatric cats
- > 70% of feline lymphomas
- Most common intestinal tumour (adenocarcinoma, MCT)
What is relevance of FeLV / FIV with lymphoma?
- Cats that are FeLV +ve are 62 times more likely to develop lymphoma
- Cats that are FeLV + FIV +ve are 80times more likely to get lymphoma
What are other aetiological factors for lymphoma?
- Genetic predisposition
- Altered expression of oncogenes, tumour suppressor genes (c-myc, N-ras)
- Epigenetic modifications
- Tobacco smoke
- Chronic inflammatory conditions (i.e. IBD)
What are different types of lymphoma in cats?
- Nodal lymphoma (multicentric)
- Alimentary lymphoma
- Mediastinal lymphoma
- Extranodal lymphoma =
-Nasal/retobulbar lymphoma
-Laryngeal lymphoma (pharynx and trachea)
-Renal lymphoma
-CNS lymphoma
-Ocular lymphoma
-Cutaneous lymphoma
What is nodal-multicentric lymphoma?
- “True” multicentric lymphoma with symmetrical generalised lymphadenopathy is rare in cats (most common form in dogs)
- Regional lymphadenopathy is more common - Submandibular lymph nodes, medial iliac lymph nodes…
- Middle aged cats - Wide range
- Generalised lymphadenopathies have been reported which mimic lymphoma - Young cats, histopathological phenomenon, generally resolve without treatment
What are clinical signs of nodal-multicentric lymphoma? What are differentials?
- CS =
- Non-painful lymph node enlargement
- Anorexia
- Depression
- Non-specific malaise
- Pyrexia
- (PU/PD)
Differentials:
* Retroviral, viral, bacterial, fungal, mycobacterial and (protozoal), infections
* (Other haemopoietic malignancies)
* Immune mediated disease
* Idiopathic forms
* Metastatic disease (regional)
What cats get mediastinal lymphoma? What are the clinical signs? What are exam findings?
- Younger cats - (Siamese cats)
- Clinical signs =
- Respiratory distress
- Regurgitation/dysphagia
- Weight loss
- Lethargy, exercise intolerance
- Cough (rare)
Examination findings:
* Palpable reduction in compressibility of cranial thorax
* Decreased lung sounds
What are Ddx for mediastinal lymphoma?
- Thymoma
- Other cranial mediastinal lymphadenopathy
- Other causes of pleural effusion =
- Congestive cardiac failure
- Pyothorax
- FIP
- (Haemothorax)
What is alimentary lymphoma? CS? Who does it affect?
- Older cats
- Insidious weight loss
- Anorexia - more common and severe in cats than dogs
- Diarrhoea (may not be observed)
- Malabsorption/PLE
- Occasionally vomiting - gastric involvement, secondary gastritis, (more common in cats than dogs)
What are Ddx for alimentary lymphoma?
- All other causes of mesenteric lymphadenopathy
- FIP - Peritonitis of other aetiologies
- IBD
- Metastatic neoplasia
- Pancreatitis
- Mycobacterial infection
What is seen with extranodal lymphoma?
- CNS - signs depend on site
- Nasal/retrobulbar - nasal discharge, epistaxis, obstruction, exophthalmos etc.
- Renal - malaise, anorexia, renomegaly (bilateral), azotaemia
Why is cutaneous lymphoma hard to treat?
- Not very responsive to chemotherapy
- Tx = interferon
How are lymphomas diagnosed?
- FNA / flow cytometry
- Biopsy - excisional (node), wedge (extranodal lesion)
- keep fresh tissue if any chance of mycobacterial / fungal disease
- PARR (PCR for antigen receptor rearrangements)
What are positive prognostic indicators for feline lymphoma?
- Achieving CR (complete response)
- small volume extranodal disease - Nasal lymphoma
- (T cell immunophenotype in indolent lymphomas)
What are negative prognostic indicators for feline lymphoma?
- Failure to achieve Complete response (CR)
- FeLV +ve status
What is Tx of lymphoma?
- (None) - 4 wks median survival
- Corticosteroids
- Multi drug regimens =
- COP (cyclophosamide, oncovin, prednisolone) - 75% CR, 1yr survival = 49%, 2yr survival = 40%
- CHOP (above +doxorubicin)
- COAP
What are side effects of lymphoma Tx?
- Myelosuppressive agents
- Probably a good idea to intermittently check urine - UTI
- Hair loss (whiskers)
- GI signs
What is Tx of alimentary lymphoma?
- Surgical excision of solitary mass lesion - Must biopsy nodes (and other organs)
- Follow up chemotherapy
- If Extensive infiltration = Staggered induction to reduce risk of perforation
- Adequate supportive therapy =
- Appetite stimulants
- O-tube
- Vitamin B12
- Gastric lymphoma very difficult to treat
- LGL lymphoma has poor response to chemotherapy
What is the outcome of feline lymphoma?
- Goal is to induce complete remission - CR is no detectable tumour
- Quality of life is paramount
- Most cats will develop drug resistance and will relapse
- Rescue therapy: single agent doxorubicin or lomustine (RR ~40%)
- Could consider radiation if local disease (e.g. nasal)
- A small percentage of cases will be cured
What are different feline leukaemia?
- Classification by cell type and progression - (Acute vs chronic, Lymphoid vs myeloid)
- Acute lymphoid leukaemia (ALL) and acute myeloid leukaemia (AML) are rapidly progressive, fatal diseases =
- High WBC counts
- Concurrent pancytopenias
- Poor prognosis (weeks-months) even with chemotherapy
*Myelodysplastic syndrome (MDS) also recognised as a precursor to acute leukaemias in FeLV positive cats
* Characterised by cytopenias (RBCs, platelets, neutrophils) without circulating neoplastic cells.
What is acute leukaemia treatment?
- Supportive therapy – very sick patients =
- Blood transfusion
- Antibiotics
- Barrier nursing
- CSF?
- Multi-agent chemotherapy protocols
- COP vs CHOP
- Addition of cytarabine infusions may improve response
- MST of ALL treated with chemotherapy is 120 days in dogs
What is chronic leukaemia?
- Neoplastic proliferation of well differentiated cells
- Chronic lymphoid leukaemia – proliferation of mature lymphocytes in bone marrow.
- Rare (T cell > B cell > T-ve, B-ve)
- Lymphocyte counts >30x109/L
- Decision to treat based on the individual (presence of CS, degree of lymphocytosis)
- Treatment with prednisolone/chlorambucil – survival times of 1-3 years reported.
- Chronic myeloid leukaemia – proliferation of mature myeloid cells (normally neutrophils) in bone marrow
- Even rarer!
- Have to exclude other causes of extreme neutrophilia; infection, immune mediated disease; paraneoplastic syndrome
- May undergo blast crisis
How is leukaemia diagnosed?
- Haematology with manual differential and smear evaluation
- Flow cytometry of peripheral blood
- Staging to evaluate extent of disease =
- Thoracic radiographs
- Abdominal ultrasound
- Cytology of liver/spleen
- Bone marrow biopsy (cytology + histology)
What are myeloma related disorders (multiple myeloma)?
- Systemic neoplastic proliferation of plasma cells results in overproduction of antibody (IgA or IgG)
- Can get local disease – extramedullary plasmacytoma which can progress to multiple myeloma
- Hyperproteinemia can lead to hyperviscosity syndrome
*-Neurological symptoms, retinal detachment, congestive heart failure (cats > dogs), hypertension, coagulopathy - Bone marrow involvement can lead to cytopenias – secondary infections
- Renal disease present in 33-50% of dogs (multifactorial due to proteinuria, hypercalcaemia, renal infiltration, urinary infection)
How is multiple myeloma diagnosed?
- Haematology, biochemistry, urinalysis =
- Non-specific, may see circulating plasma cells
- Proteinuria (Bence-Jones proteins)
- Hypercalcemia
- Hyperglobulinemia
- Serum protein electrophoresis - Monoclonal gammopathy
- Diagnostic imaging = Hepatosplenomegaly, Osteolytic bone lesions
- Cytology = Liver, spleen + bone marrow
In dogs, for multiple myeloma diagnosis, what is needed?
- In dogs have to fulfil two of the following criteria =
1. Monoclonal gammopathy
2. Radiographic evidence of osteolytic bone lesions
3. >5% neoplastic plasma cells or >10-20% plasmacytosis in the bone marrow
4. Bence-Jones proteinuria
What is treatment of multiple myeloma?
- Supportive care =
- Blood transfusions
- Plasmaphoeresis
- Antibiotics if secondary infection
- Therapy for hypercalcaemia
Systemic disease =
* Prednisolone (~ 40 days)
* Chemotherapy =
- Prednisolone 0.5mg/kg SID reducing to EOD – stop after 2 months
- Melphalan 0.1mg/kg SID reducing to 0.05mg/kg SID
- Cumulative myelosuppression is seen – perform haematology q2 weeks then monthly.
- Median survival of 540 days reported (dogs)
* Local extramedullary plasma cell disease may be treated surgically if no systemic involvement
