For acute myeloid leukemia (AML), test results play a vital role in determining the most appropriate treatment option. Expert Dr. Ellen Ritchie reviews key tests used to pinpoint a patient’s specific AML, how the test results are utilized, and important questions patients should ask their doctor about AML testing.
Dr. Ellen K. Ritchie is assistant professor of medicine and a member of the Leukemia Program at the Weill Cornell Medical College of Cornell University and the New York Presbyterian Hospital. More about Dr. Ritchie, here.
So, let’s help our audience be clear about basic testing. What tests are necessary to help understand a patient’s specific disease at diagnosis?
I mean certainly it’s important to do a physical exam and to find out what the general health of the patient is. In order to evaluate an AML, or any other leukemia, I look at the peripheral blood smear. To look at what I think the type of leukemia might be that I am dealing with. There are some leukemias that have particular way that they look like acute promyelocytic leukemia for which there is a designated therapy which works.
And you can tell that just by looking at a peripheral blood slide. The next test is always a bone marrow biopsy. Patients are not delighted that that is a test, but it is a test that can be done in the office, usually within 15 to 20 minutes. And that test gives us a lot of information. It gives us information about what type of AML it is, what are the markers on the outside of the cell, it gives us information about the chromosomes inside the leukemia cell. Are there missing chromosomes, or rearranged chromosomes? And if there are, that can be very relevant to the prognosis. And lastly, it’s sent for a particular mutations or markers. So, we look for IDH3 mutations, we look for FLT3 mutations, we look for IDH1 and IDH2 mutations, and we do an entire myeloid panel. Which is about 44/45 genes that are most commonly mutated in patients with AML. So that’s the initial work-up for any AML patient.
You mentioned markers, Dr. Ritchie. What is genomic, or biomarker testing?
So, we’re looking really at most specifically at mutations inside individual genes that might be in your leukemia cell. So, there are some mutations actually that confer a better prognosis. Like NPM1 or CEPBA, those can be more positive type of prognosis than some of the others.
But we’re also looking for markers that might be targetable with certain therapies that we have. So, if you have a FLT3 ITD or TKD, we actually have particular drugs which can target those particular mutations. There are also drugs that are FDA approved to treat IDH1 and IDH2 mutations.
There are certain mutations that have a relatively poor prognosis, like TP53 for which there are clinical trials which are available, which specifically are meant to target patients who have those sorts of mutations. And there’re other clinical trials using the FDA-approved drugs that I just mentioned, for FLT3, for IDH1 and IDH2 and combining it with other agents to try and improve outcome in AML patients.
Some patients may not know if they’ve received these important tests, so what key questions should they be asking their physician about testing?
So, physicians, they – financial coverage of the mutational testing is not uniform across the country and across insurances. So, Medicare and different Medicare insurances and some of the private insurances all vary in their coverage.
So, in my clinic, I am asking – I prefer the test that we do in house at Cornell. But it’s important that I ask, what will their insurance cover. And make sure that I send the appropriate testing that will be covered by insurance. There are some insurances that will not cover this type of testing. So, it is a real question for the patient, when you go to see the doctor to say, are you going to do mutational NGS testing?
And, will my insurance cover this? Hopefully most – if Medicare adopts the coverage of these types of mutational testing, it’s often true that private insurance will eventually pick this up. But it’s a murky field, and it’s really important to talk to your doctor about this. The cost of the bone marrow biopsy, and the chromosomal evaluation is nearly always covered by insurance.