Practice Pearl 1: The Importance of Cytogenetic Results in AML
Yehuda Deutsch, MD, discusses the cytogenetic tests used in acute myeloid leukemia (AML), and the importance of waiting for these results.
Yehuda Deutsch, MD: Because of the importance of cytogenetic and molecular results in the diagnosis, treatment, and outcomes in AML, it is really important that we have [some of] these results before starting treatment. These cytogenetic and molecular tests are usually collected with the bone marrow biopsy and aspiration. If there is no aspiration, or if we’re unable to repeat a bone marrow biopsy or get those results, sometimes we’re able to do this through the peripheral blood.
The tests that we need to do are cytogenetic analysis, which includes chromosome analysis or karyotype; FISH [fluorescence in situ hybridization] testing; as well as molecular testing, either with NGS (next-generation sequencing) or PCR. There are panels that can be performed, that include an AML-type of FISH panel or MDS-FISH panel. In terms of molecular testing, there also are single mutations that can be looked for or a full panel, a full myeloid panel. We typically collect these specimens. In terms of the molecular testing, it’s important to have testing for those mutations that are prognostic, that are predictive, that are biomarkers, and that can be targeted. So, these include, but they’re really not limited to, FLT-3 mutations, including the ITD and TKD, IDH1, IDH2 mutations, TP-53, ASXL1, RUNX1, as well as many other mutations.
Katie Culos, PharmD, BCOP: Yehuda, you mentioned that there’s obviously a wide variety of tests, and we want to collect as much information as we can prior to treating. Can you give us a little insight into the turnaround time for these different labs, and how long potentially the picture could take to come together?
Yehuda Deutsch, MD: With patients with AML, typically patients are quite ill, and they often need to start chemotherapy treatment quickly. However, we know the importance of these cytogenetic and molecular tests. So, we often do wait for some of these results before deciding on treatment. At some institutions, there can be a quicker turnaround time. However, some of these tests, including myeloid NGS panels, can take a week or even longer. However, the tests that can be expedited typically are FISH analysis, which can help determine if patients have core binding factor leukemia, including APL [acute promyelocytic leukemia], which is treated completely differently, as well as FLT3/PCR testing, which can be done quickly, with probably a turnaround time of about 48 to 72 hours.
Katie Culos, PharmD, BCOP: You also mentioned that when you’re sending your FISH analysis you can conduct different panels based on focusing for more abnormalities that may be either AML or MDS focused. Is that something where you’re going to take the patient’s age into consideration, before you order these types of tests?
Yehuda Deutsch, MD: We always take into account patients’ age and their comorbidities, especially for the older patients who may have more comorbidities, who may not tolerate intensive induction chemotherapy and also have an increased risk of having an antecedent bone marrow disorder, such as myelodysplastic syndrome. So, those, for sure, are the patients for whom we would definitely try and expedite some of their cytogenetic and molecular testing, to check to see if they have any MDS-related types of changes.