The Hematologist

March-April 2017, Volume 14, Issue 2

ASH-CAP Guidelines for the Diagnosis of Acute Leukemia

Daniel A. Arber, MD Professor and Chair, Department of Pathology
University of Chicago, Chicago, IL
Tracy I. George, MD Professor of Pathology; Director of the Hematopathology Fellowship Program
University of New Mexico School of Medicine, Albuquerque, New Mexico
Payal Sojitra, MD Hematopathology Fellow, Department of Pathology
University of New Mexico School of Medicine, Albuquerque, NM

Published on: March 01, 2017

The 2016 revision to the World Health Organization classification of acute leukemia now includes 37 types of acute leukemia and related neoplasms and five provisional entities. This revision incorporates even more complex genetic testing for the diagnosis and prognostic determination of acute leukemia.1 These new and improved diagnostic and prognostic markers in turn have resulted in an increased demand for a variety of laboratory tests. Currently available guidelines such as the National Comprehensive Cancer Network (NCCN) guidelines for acute myeloid leukemia (AML) include some testing recommendations, but are primarily treatment recommendations.2-3 The European Leukemia Net’s AML recommendations incorporate some mutation testing, but they do not offer comprehensive guidelines.4 In recognition of the complexity involved in the diagnosis of acute leukemia, a well-timed manuscript on guidelines has been developed by ASH and the College of American Pathologists (CAP) for the proper diagnosis and prognosis determination for the initial workup of patients with acute leukemia.5 To form these guidelines, an expert panel performed systematic and unbiased reviews of the medical literature to answer six key questions (Table 1). Answers to these six questions resulted in 27 recommendations (Table 2). These recommendations were graded based on the quality of evidence and strength of recommendations.

Taking a step back, one could ask, “Do physicians need such guidelines?” To answer this question, CAP conducted a survey among hematologists/oncologists and pathologists on the current practice of ordering tests for the diagnosis of acute leukemia.6 The survey showed that nearly 100 percent of respondents reported performing morphologic assessment and flow cytometry analysis, and 96 percent of respondents reported performing conventional cytogenetics. Surprisingly, far fewer respondents reported performing molecular genetic testing for AML (71%) or for acute lymphoblastic leukemia (ALL; 55%). Limitations of the survey included a preponderance of academic hematopathologists among responders, which could serve as a source of bias and inaccuracy due to self-reporting. The reader could rightly ask, “What are the actual current clinical practice patterns by physicians for patients with acute leukemia?”

An observational cohort study reported at the 2016 ASH Annual Meeting by Dr. Tracy George and colleagues sheds some light onto this topic. The CONNECT MDS/AML Disease Registry (NCT01688011) was used to assess current clinical practice patterns in AML and to compare how these practices align with WHO 2008 recommendations.7 The disease registry includes 64 community and 15 academic centers and involves prospective reporting of clinical findings, laboratory results, and pathology test results, which are then centrally reviewed. The data showed that flow cytometry and conventional karyotyping were done in most cases (98% and 92%, respectively), but a manual blast count was performed only in 67 percent of AML patients at diagnosis. Approximately 10 percent of blasts counts were primarily evaluated by flow cytometry, which is highly discouraged per WHO 2008 recommendations, as it may both underestimate and overestimate the blast count. Molecular genetic testing was performed in only 67 percent of patients. A multivariate model identified two independent significant predictors of molecular genetic testing, including age equal to 65 years or younger, and if the patient was enrolled at an academic site. Thus, these results would argue that guidelines are needed for the diagnosis of acute leukemia and the CONNECT AML/MDS disease registry is uniquely positioned to monitor the implementation of the ASH-CAP guidelines.

In studying the ASH-CAP guidelines, their strength lies in the grading of the quality of evidence. Each guideline statement is accompanied by the strength of recommendation allowing the reader to ascertain the impact of each guideline statement. While the initial guideline statements may appear quite obvious to the practicing hematologist and pathologist, they clearly delineate the samples and specimen types necessary for the diagnostic workup. Statement 12 clearly addresses the impact of minimal residual disease testing and statements 13 to 21 offer practical recommendations on the genetic workup of different types of acute leukemia. Survey results and data from the CONNECT AML/MDS registry suggest that physicians are not currently ordering enough genetic testing or the proper genetic tests, so these statements are helpful. The final statements refer to where testing is performed and what results should be reported, including the recommendation that WHO terminology be used for the final diagnosis and classification of acute leukemia.

To summarize, ASH and CAP have published guidelines on testing for the initial workup of acute leukemia that will be helpful in guiding all physicians and allied health professionals on the proper diagnostic workup of acute leukemia. The guidelines are available now on www.archivesofpathology.org. In addition to the full guideline, the recommendations and diagnostic algorithms will also be available in late March 2017 at www.hematology.org/pocketguides, in a printed pocket guide, and digitally in the ASH Pocket Guides app.

 Table 2. Summary and Strength of Recommendations
 Guideline StatementStrength of Recommendation 
1. The treating clinician should provide relevant clinical data or ensure that this is readily accessible by the pathologist.Strong Recommendation 
2. The treating clinician should provide relevant physical examination and imaging findings or ensure that these are readily accessible by the pathologist. 

Recommendation 

3. The pathologist should review recent or concurrent complete blood counts (CBCs) and leukocyte differentials and evaluate a peripheral blood smear.  Strong Recommendation 
4. The treating clinician or pathologist should obtain a fresh bone marrow aspirate for all patients suspected of acute leukemia, a portion of which should be used to make bone marrow aspirate smears for morphologic evaluation. If performed, the pathologist should evaluate an adequate bone marrow trephine core biopsy, bone marrow trephine touch preparations, and/or marrow clots, in conjunction with bone marrow aspirates. Strong Recommendation 
5. In addition to morphologic assessment, the pathologist or treating clinician should obtain sufficient samples and perform conventional cytogenetic analysis, appropriate molecular genetic and/or FISH testing, and flow cytometric immunophenotyping. The flow cytometry panel should be sufficient to distinguish acute myeloid leukemia, T-ALL (including early T-cell precursor leukemia), B-ALL, and acute leukemia of ambiguous lineage on all patients diagnosed with acute leukemia. Molecular genetic and/or FISH testing does not, however, replace conventional cytogenetic analysis. Strong Recommendation 
6. For patients with suspected or confirmed acute leukemia, the pathologist may request and evaluate cytochemical studies to assist in the diagnosis and classification of AML. Expert Consensus Opinion 
7. The treating clinician or pathologist may use cryopreserved cells or nucleic acid, formalin fixed, non-decalcified paraffin-embedded (FFPE) tissue, or unstained marrow aspirate or peripheral blood smears obtained and prepared from peripheral blood, bone marrow aspirate or other involved tissues for molecular or genetic studies in which the use of such material has been validated. Such specimens must be properly identified and stored under appropriate conditions in a laboratory that is in compliance with regulatory and/or accreditation requirements.Recommendation 
8. For patients with ALL receiving intrathecal therapy, the treating clinician should obtain CSF. The treating clinician or pathologist should ensure that a cell count is performed and that examination/enumeration of blasts on a cytocentrifuge preparation is performed and is reviewed by the pathologist.  Strong Recommendation 
9. The treating clinician may obtain a CSF sample when there is no clinical contraindication. The treating clinician or pathologist should ensure that a cell count is performed and that examination/enumeration of blasts on a cytocentrifuge preparation is performed and is re viewed by the pathologist. Expert Consensus Opinion 
10. For patients with suspected or confirmed ALL, the pathologist may use flow cytomtry in the evaluation of CSF. Recommendation 
11. For patients who present with extramedullary disease without bone marrow or blood involvement, the pathologist should evaluate a tissue biopsy and process it for morphologic, immunophenotypic, cytogenetic, and molecular genetic studies, as recommended for the bone marrow. Strong Recommendation 
12. For patients with suspected or confirmed acute leukemia, the pathologist or treating clinician should ensure that flow cytometry analysis or molecular characterization is comprehensive enough to allow subsequent detection of MRD. Strong Recommendation 
13. For pediatric patients with suspected or confirmed B-ALL, the pathologist or treating clinician should ensure that testing for t(12;21)(p13;q22); ETV6-RUNX1, t(9;22)(q34;q11.2); BCR-ABL1, KMT2A (MLL) translocation, iAMP 21, and trisomy 4 and 10 is performed.Strong Recommendation 
14. For adult patients with suspected or confirmed B-ALL, the pathologist or treating clinician should ensure that testing for t(9;22)(q34;q11.2); BCR-ABL1 is performed. In addition, testing for KMT2A (MLL) translocations may be performed. Strong Recommendation for testing for t(9;22)(q34;q11.2) and BCR-ABL1; Recommendation for testing for KMT2A (MLL) translocations 
15. For patients with suspected or confirmed ALL, the pathologist or treating clinician may order appropriate mutational analysis for selected genes that influence diagnosis, prognosis, and/or therapeutic management that includes, but is not limited to: PAX5, JAK1, JAK2, and/or IKZF1 for B-ALL and NOTCH1 and/or FBXW7 for T-ALL. Testing for overexpression of CRLF2 may also be performed for B-ALL.  Recommendation 
16. For pediatric and adult patients with suspected or confirmed AML of any type, the pathologist or treating clinician should ensure that testing for FLT3-ITD is performed. The pathologists or treating clinician may order mutational analysis that includes but is not limited to: IDH1, IDH2, TET2, WT1, DNMT3A, and/or TP53 for prognostic and/or therapeutic purposes. Strong Recommendation for testing for FLT3-ITD; recommendation for testing for other mutational analysis 
17. For adult patients with confirmed core binding factor (CBF) AML (AML with t(8;21)(q22;q22.1)); RUNX1-RUNX1T1 or inv(16)(p13.1q22)/t(16;16)(p13.1;q22); CBFB-MYH11, the pathologist or treating clinician should ensure that appropriate mutational analysis for KIT is performed. For pediatric patients with confirmed core binding factor AML (AML with t(8;21)(q22;q22.1)); RUNX1-RUNX1T1 or inv(16)(p13.1;q22)/t(16;16)(p13.1;q22); CBFB-MYH11, the pathologist or treating clinician may ensure that appropriate mutational analysis for KIT is performed. Strong Recommendation for testing for KIT in adult patients with CBF AML; expert consensus opinion for testing for KIT in pediatric patients with CBF AML 
18. For patients with suspected APL, the pathologist or treating clinician should also ensure that rapid detection of PML-RARA is performed. The treating clinician should also order appropriate coagulation studies to evaluate for DIC. Strong Recommendation 
19. For patients other than those with confirmed core binding factor AML, APL, or AML with myelodysplasia-related cytogenetic abnormalities, the pathologist or treating clinician should also ensure that mutational analysis for NPM1, CEBPA, and RUNX1 is also performed.Strong Recommendation 
20. For patients with confirmed acute leukemia, no recommendation is made for or against the use of global/gene specific methylation, miRNA expression, or gene expression analysis for diagnosis or prognosis. No Recommendation 
21. For patients with confirmed mixed phenotype acute leukemia, the pathologist or treating clinician should ensure that testing for t(9;22)(q34;q11.2); BCR-ABL1, and KMT2A (MLL) translocations is performed. Strong Recommendation 
22. All laboratory testing performed for the initial work-up and diagnosis of a patient with acute leukemia must be performed in a laboratory that is in compliance with regulatory and/or accreditation requirements. Strong Recommendation 
23. If after examination of a peripheral blood smear, it is determined that the patient will require immediate referral to another institution with expertise in the management of acute leukemia for treatment, the initial institution should, whenever possible, defer invasive procedures including bone marrow aspiration and biopsies to the treatment center to avoid duplicate procedures, associated patient discomfort, and additional costs.Strong Recommendation 
24. If a patient is referred to another institution for treatment, the primary institution should provide the treatment center with all laboratory results, pathology slides, flow cytometry data, cytogenetic information, and a list of pending tests at the time of the referral. Pending test results should be forwarded as they become available. Strong Recommendation 
25. In the initial report, the pathologist should include laboratory, morphologic, immunophenotypic, and, if performed, cytochemical data, on which the diagnosis is based, along with a list of any pending tests. The pathologist should issue addenda/amended reports when the results of additional tests become available. Strong Recommendation 
26. The pathologist and treating clinician should coordinate and ensure that all tests performed for classification, management, predicting prognosis and disease monitoring are entered into the patient's medical records. Strong Recommendation 
27. Treating clinicians and pathologists should use the current World Health Organization (WHO) terminology for the final diagnosis and classification of acute leukemia. Strong Recommendation 

 

References

  1. Arber DA, Orazi A, Hasserjian R, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016;127:2391-2405.
  2. O'Donnell MR, Tallman MS, Abboud CN, et al. Acute myeloid leukemia, version 2.2013. J Natl Compr Canc Netw. 2013;11:1047-1055.
  3. O'Donnell MR, Abboud CN, Altman J, et al. NCCN Clinical Practice Guidelines Acute myeloid leukemia. J Natl Compr Canc Netw. 2012;10:984-1021.
  4. Döhner H, Estey EH, Amadori S, et al. Diagnosis and management of acute myeloid leukemia in adults: recommendations from an international expert panel, on behalf of the European LeukemiaNet. Blood. 2010;115:453-474.
  5. Arber DA, Borowitz MJ, Cessna M, et al. Initial diagnostic workup of acute leukemia: Guidelines from College of American Pathologists and the American Society of Hematology. Arch Pathol Lab Med and Blood. 2017.
  6. George TI, Tworek JA, Thomas NE, et al. Evaluation of testing of acute leukemia samples: survey result from the College of American Pathologists. Arch of Pathol Lab Med [in press]. 2017.
  7. George TI, Erba HP, Steensma DP, et al. Current Diagnosis Patterns for Acute Myeloid Leukemia (AML) in Clinical Practice Compared with World Health Organization (WHO) 2008 Recommendations: Outcomes from the CONNECT Myelodysplastic Syndromes (MDS) and AML Disease Registry. Blood. 2016;128:3548.

Conflict of Interests

Dr. Somitra and Dr. Arber indicated no relevant conflicts of interest. Dr. Arber is the co-chair of the CAP/ASH guideline group. Dr. George has been a consultant for Celgene. back to top