Page 1177 - Cote clinical veterinary advisor dogs and cats 4th

Leukemias, Chronic 589

eosinophilic enteritis, allergic diseases, para- • Phlebotomy for PV or plasmapheresis for PROGNOSIS & OUTCOME
hyperviscosity syndrome
neoplastic syndrome, hypoadrenocorticism • Nutritional support CLs are indolent. Long-term survival is possible
VetBooks.ir • Platelets: ET, hyperadrenocorticism, iron- Chemotherapy: special handling requirements with CLL. There is less information for MPN. Diseases and Disorders
• Basophils: CBL, mast cell neoplasia, dirofi-
lariasis
needed, and severe adverse effects possible;
• CLL: 80%-90% respond to chemotherapy;
deficiency anemia, hemolytic anemia,
survival of 1.5 years for cats. Conflicting
oncologist is recommended:
recovery from severe hemorrhage, splenec- consultation with or referral to a veterinary survival times of 1-3 years for dogs; median
tomy, chronic inflammatory disorders, acute • CLL: treatment recommended for clinical reports of survival with T-cell > B-cell CLL
infection signs, cytopenias, organ enlargement due to or no difference. Atypical phenotype has pos-
• Erythrocytes: relative erythrocytosis infiltration, significant lymphadenopathy, sibly shorter survival. For B-cell CLL, older
(dehydration, diuretics); breed variation or lymphocyte counts > 60,000/mcL. dogs have longer survival. For T-cell CLL >
(sighthounds); absolute erythrocytosis Consider earlier treatment for dogs with 30,000 lymphocytes/mcL or anemia, shorter
(PV, chronic hypoxemia [e.g., right-to-left atypical phenotype CLL and young dogs survival. Transformation into lymphoma/
cardiac shunts, chronic respiratory disease, with B-cell CLL. If not treated, recheck q acute leukemia has a poor prognosis.
high altitude], paraneoplastic erythropoi- 1-2 months, and start treatment if indicated. • MPN: prognosis depends on type. There
etin); splenic contraction Protocol includes prednisone (dogs) 1 mg/ is little or no information describing the
kg PO q 24h × 7 days, decrease to 0.5 mg/ prognosis for some of these conditions.
Initial Database kg q 48h; prednisolone (cats) 1 mg/kg PO ○ CML/CBL: dogs may live ≥ 1 year with
2
• Laboratory tests q 24h, and chlorambucil 20-30 mg/m PO treatment.
○ CBC: high leukemic cell count. Counts q 14 days (p. 609). Other drugs are used ○ PV: survival times of 1 to > 6 years
can be very high (hundreds of thousands for lymphoma when it progresses (referral reported
or higher number of cells/mcL); for PV, to/consultation with veterinary oncologist ○ CEL: in cats, limited response to treat-
packed cell volume (PCV) typically is recommended). ment; survival times of a few months.
60% to ≥80%. Mature and immature • MPN: depends on diagnosis; referral to/ Unclear if dogs develop CEL, but if they
forms of affected cell line may be present. consultation with veterinary oncologist is do, it is possibly prednisone responsive.
Cytopenias are not generally observed recommended. ○ ET: typically nonresponsive to treatment
until leukemic cell counts are very high. ○ PV, CML, and CEL: hydroxyurea but long-term control (>500 days) with
Mild anemia occurs with CLL and MPN. (dogs) 30 mg/kg PO q 24h for 7-10 busulfan in one dog
○ Serum biochemistry profile and urinalysis: days, then 15 mg/kg PO q 24h; (cats)
to evaluate overall health and identify 125 mg PO q 3-4 days. Dosages are PEARLS & CONSIDERATIONS
paraneoplastic hyperglobulinemia or adjusted based on response and adverse
hypercalcemia events. It is important to know poten- Comments
○ FeLV/FIV ELISA: typically negative tial side effects of hydroxyurea before • CLs have a slow onset and progress slowly.
○ Erythropoietin level: normal or low with using this drug. Initially, PV may be Patients are initially normal and then show
PV; may be high with autonomous eryth- managed with phlebotomy and fluid nonspecific signs.
ropoietin source (e.g., renal neoplasm) replacement. • Diagnosis is based on identifying proliferating
• Bone marrow cytology (p. 1068): indicated ○ Tyrosine kinase inhibitors (e.g., toceranib) mature hematopoietic cells in blood and/
if CBC (with cytologic exam of blood smear) may be an option for CML. Anecdotal or bone marrow with flow cytometry to
and flow cytometry insufficient to make the responses have been observed by the immunophenotype if lymphocytic.
diagnosis author. • There is diagnostic overlap between CLL
• Cytology of enlarged peripheral lymph nodes and small cell lymphoma.
• Imaging for staging and to identify concur- Possible Complications • Patients with CL can enjoy long survival
rent abnormalities • Myelosuppression: neutropenia, thrombo- times.
○ Thoracic radiography cytopenia • Research is characterizing molecular abnor-
○ Abdominal ultrasonography ○ Secondary infection malities in CL as targets for therapy and
• Chronic bone marrow injury prognostic indicators.
Advanced or Confirmatory Testing • Hydroxyurea: methemoglobinemia (cats),
Flow cytometry for CLL immunophenotyping anemia, skin/hair/nail changes Technician Tips
• GI toxicosis • Patients with CL often undergo chronic
TREATMENT • Rare hepatic, renal, pulmonary, or neurologic chemotherapy.
toxicoses • CBCs are monitored for chronic bone
Treatment Overview marrow injury and relapse.
Goals are to eradicate leukemic cells and provide Recommended Monitoring • Owners should be educated on monitoring
symptomatic care. Early in the disease, treat- • Depends on diagnosis and severity their pet and precautions to avoid chronic
ment may not be required. • Physical examinations: weekly during exposure to chemotherapy.
induction period; q 1-2 months after on
Acute and Chronic Treatment maintenance therapy SUGGESTED READING
Supportive care (if indicated) • CBC: monitor myelosuppression and remis- Vail EM, et al: Hematopoietic tumors. In Withrow
• Broad-spectrum antibiotic therapy for sion status, weekly during induction period SJ, et al, editors: Withrow and MacEwen’s Small
treating/preventing secondary infections if and q 1-2 months on maintenance therapy animal clinical oncology, ed 5, St. Louis, 2013,
severe neutropenia (p. 152) to monitor for chronic bone marrow injury Saunders, pp 627-678.
• Intravenous fluids: for infection, fever, and relapse AUTHOR: Nicole C. Northrup, DVM, DACVIM
inappetence/dehydration • Serum biochemistry profile, urinalysis: 1 EDITOR: Kenneth M. Rassnick, DVM, DACVIM
• Avoid jugular venipuncture if severe throm- month after starting therapy and then q
bocytopenia or hyperviscosity syndrome 3-4 months
• Transfusions (p. 1169); uncommonly needed

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