Published on July 25, 2017
How are MPNs diagnosed?
As part of a recent MPN Town Meeting in partnership with Robert H. Lurie Comprehensive Cancer Center in Chicago, Dr. Brady Stein and Dr. Naveen Pemmaraju discuss how myeloproliferative neoplasms (MPNs)—essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)—are diagnosed. The experts discuss the necessary blood tests, including platelet counts, and provide a thorough explanation of bone marrow biopsy.
This town meeting was sponsored by Incyte Corporation. It was produced by Patient Power in partnership with the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
Transcript | Diagnosing MPNs: Blood Tests & Bone Marrow Biopsies
Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.
What Methods Are Used for Diagnosing MPNs?
So, Dr. Pemmaraju, how do we figure out if someone has an MPN? What diagnostics get us to that diagnosis?
Well, there are a couple of different avenues that I see on a weekly basis. One of the most common, nowadays, is usually the abnormal CBC or blood counts, complete blood count, CBC. This will be a patient, someone who has been having some of the symptoms that Lindsey nicely brought up. Tough to differentiate from are these the symptoms of “normal aging,” whatever that is.
So the patient and the PCP, primary care provider, do a blood count, a series of tests, and there’s a blood count abnormality. Well, what does that mean? Well, that can come in a couple of different varieties. One is called anemia, which simply means low red blood cell count or low hemoglobin, if you’ve heard those terms or have that. So this is something that comes up very frequently. Red blood cells are essential to carrying oxygen and nutrition to every part of your body, your brain, your heart, your muscles. So, a slowing, a fatigue, a profound difference in the change of activity from before, this can manifest as this drop in the hemoglobin.
Oftentimes, in the local doctor’s office, folks will be ruled out for GI bleeding, colonoscopy, all of these important things that have to happen. But, at the end of the day, once those are ruled out, they’re, oftentimes, referred to the hematologist. The second situation is the low platelets or high platelets. Thrombocytosis or thrombocythemia. And then, lastly, I would say the high white blood cell count or a low white blood cell count. So abnormalities of the blood count is one way to come.
And then, of course, that leads to a bone marrow biopsy, hematology referral. The second way that folks are coming to us I think is actually very important. Brady and I started to see this when we were finishing our training back at Hopkins together when the JAK2 mutation was first elucidated in 2005 is that you can have a series of young patients who present with a blood clot or some catastrophic or devastating abnormality first. Young person minding their business has a blood clot in an unusual area, stomach area called the Budd-Chiari clot, for example. In the brain area called the cerebral sinus thrombosis.
And, actually, an astute clinician will send a JAK2 mutation or some other test at that time found to be positive then referred to the hematologist. So this is a second new way that people are coming to us as a presentation of one of these situations.
What Is a Bone Marrow Biopsy?
You used three words in what you just told us that tend to strike a little bit of fear in my heart on a regular basis.
And those three words are bone marrow biopsy. Why, Dr. Stein, do we need to drill holes in our hips?
So that’s a good question. And I think there’s a lot to talk about with the bone marrow biopsy. And I think, here, we may be a little different than many other places. First of all, you can’t make a diagnosis with myelofibrosis without a bone marrow biopsy. So it’s absolutely essential to establishing a diagnosis. So you can’t have a diagnosis without it in myelofibrosis. In polycythemia vera, you can make a diagnosis without a bone marrow biopsy. Polycythemia vera has the most unique features of all three.
Now, all three can mimic one another. They can all look like one another at the beginning. As time passes, one can change from the next. So this concept of mimicry, one looks like the next, has been described for 65 years. And so, sometimes, getting at a diagnosis can be very, very difficult with PV, it can be obvious to all of us because, if the red blood cell count is extremely high, and there’s no other explanation, and we find a JAK2 mutation, which is found in 96 percent of patients with polycythemia vera, we’re pretty confident about the diagnosis. So, with PV, there are other features, and we don’t have to have it.
A bone marrow in polycythemia vera really helps with prognosis. It helps us try to predict what might happen in 10 to 15 years. ET certainly can have a unique presentation. It’s always a high platelet count.
But a high platelet count can come up with any of the three. And 90 percent of patients with ET have a mutation or a marker, JAK2, calreticulin, some of you may have that, or another mutation, the rarest, called MPL. So you could have a high platelet count in a mutation, and it can look to all the world like ET, but in the last decade, there’s been another entity called early myelofibrosis or pre-fibrotic myelofibrosis. It means that there are features of myelofibrosis that are really, really subtle. There may not necessarily be scarring, but there’s a change in the appearance of the bone marrow.
The only way we can know if it’s ET or a really early form of myelofibrosis is a bone marrow. And so, what we talk about with our patients who are in that situation, we say this is about a long-term impact. It’s not going to change the way we treat you now.
But it tells us what may or may not happen in 10 to 15 years. So, in our clinic, we have to do a bone marrow for myelofibrosis. For polycythemia vera, if there’s a question about the diagnosis, there are gray areas in any one of these, we may consider it. If a patient is on the younger side, and it really is important for all of us to set expectations, I think it’s wise. With ET, we have an informed discussion. And we say everyone knows this can be a really uncomfortable procedure. We know it, and we know that our patients have often experienced discomfort from it. It’s not a small thing.
It’s a bedside procedure. It’s an outpatient procedure. But it’s not a small thing, and we take it very, very seriously. We have a discussion. This is what we think we have in terms of a diagnosis. It’s very, very likely ET. There’s another part of this that it could be. The implications are long term rather than immediate. And we let the patients decide.
I think it’s different, and I can’t speak to what happens at other universities, but that’s how all of our discussions go here. And we have an open dialogue about it. So there’s one more part I want to bring up, if it’s okay, and that’s the diagnostic part. The follow-up part is another really important thing. And we’ll see patients—we see patients from all over, and we have seen patients who have had a yearly bone marrow. And in the last—when should my bone marrow be, we tend to react in terms of bone marrow biopsies. We don’t schedule a yearly bone marrow for no reason. And that’s different than other diseases.
And I can’t speak to acute leukemia or lymphoma, diseases that I don’t treat. But, in this entity, we tend to react to a clinical change. So if things are very, very stable and you’re satisfied with your symptoms or your therapy, and we’re satisfied as well, and we’re not seeing a feature of progression or something unexpected or surprising, then we don’t have to do it.
So we tend to do bone marrows more on the reactive side, and especially if it’s going to change something for you and for us. Is it going to lead to action? Are we going to do something different about your management? So that’s one thing that comes up a lot about monitoring. Bone marrows can be one part of monitoring, but there are a lot of other things that go into monitoring.