Hairy Cell Leukemia
National Comprehensive Cancer Network
Morphological evaluation of peripheral blood smears, bone marrow biopsy with or without aspirate, and adequate immunophenotyping by immunohistochemistry (IHC) or flow cytometry are essential to establish a diagnosis of hairy cell leukemia (HCL).
The initial workup should include a thorough physical examination with attention to node-bearing areas (although presence of peripheral lymphadenopathy is uncommon), size measurements of the liver and spleen, and performance status evaluation.
A bone marrow biopsy with or without aspirate should be obtained.
Laboratory assessments should include CBC with differential, serum lactate dehydrogenase levels, and a comprehensive metabolic panel. In particular, close evaluation of renal function is advised, considering the renal route of excretion of drugs used in HCL treatment.
Hepatitis B virus (HBV) testing is recommended due to the increased risk of viral reactivation associated with the use of immunotherapy and/or chemotherapy.
Indications for treatment initiation may include symptomatic disease with excessive fatigue; physical discomfort due to splenomegaly/hepatomegaly; unexplained weight loss (>10% within prior 6 months); cytopenias (hemoglobin <11g/dl, platelets <100,000/mcl, and/or absolute neutrophil count <1000/mcl); progressive lymphocytosis; or lymphadenopathy.
First-line therapy with purine analogues (cladribine or pentostatin) is recommended for patients with indications for treatment.
Standard-dose purine analogues should not be administered to patients with active, life-threatening, or chronic infection. Active infection should be treated before initiating treatment with standard-dose purine analogues. If it is not possible to control infection, initiating treatment with low-dose pentostatin should be considered to secure a durable response before using standard-dose purine analogues.
Complete response (CR) is defined as normalization of blood counts (hemoglobin >11 g/dl without transfusion, absolute neutrophil count >1,500/mcl, platelets >100,000/mcl), absence of HCL cells by morphological examination of bone marrow biopsy or peripheral blood samples, regression of splenomegaly by physical examination, and absence of disease symptoms.
Observation until indications for additional treatment (eg, disease relapse) is recommended for patients who achieve a CR with initial purine analogue therapy. Enrollment in a clinical trial and treatment with an alternative purine analogue ± rituximab, interferon-alfa, or rituximab monotherapy (if unable to receive a purine analogue) are options for patients with less than a CR to initial therapy.
Patients with disease relapse ≥2 years after achieving CR to initial therapy with a purine analogue may benefit from re-treatment with the same purine analogue with or without rituximab. Other options include treatment with an alternative purine analogue with or without rituximab or rituximab monotherapy (if unable to receive a purine analogue). Enrollment in a clinical trial and treatment with an alternative purine analogue ± rituximab, interferon-alfa, or rituximab monotherapy (if unable to receive purine analogue) are options for patients with disease relapse within 2 years after achieving CR to initial therapy.
Clinical trial, ibrutinib, or vemurafenib with or without rituximab are appropriate options for progressive disease after second-line therapy.
Acyclovir or an equivalent is recommended for herpes virus prophylaxis, and trimethoprim-sulfamethoxazole or an equivalent is recommended for Pneumocystis jiroveci pneumonia prophylaxis. Anti-infective prophylaxis for a minimum of 2 months and until CD4 count is ≥200 cells/mm3 is recommended for all patients requiring treatment. Broad-spectrum antibacterial prophylaxis should be considered for patients with neutropenia.
Reference
Wierda WG, Byrd JC, Abramson JS, et al. Hairy Cell Leukemia, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology. Natl Compr Canc Netw. 2017 Nov;15(11):1414-27. https://www.jnccn.org/content/15/11/1414.long
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: John Anello, Brian Feinberg, John Heinegg, et. al. New Clinical Practice Guidelines, December 2017 - Medscape - Dec 06, 2017.
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