What are signs that essential thrombocythemia (ET), polycythemia vera (PV) or myelofibrosis (MF) may be progressing? Dr. Jeanne Palmer, of the Mayo Clinic in Arizona, reviews factors that may indicate progression and discusses how blood counts are used in disease monitoring.
Dr. Jeanne Palmer is a hematologist specializing in myeloproliferative neoplasms (MPNs) and bone marrow transplant at the Mayo Clinic in Arizona. Dr. Palmer also serves as Director of the Blood and Marrow Transplant Program and is Vice Chair and Section Chief for Hematology. Learn more about Dr. Palmer, here.
Okay. Katie had this question. “What are the signs of progression from PV to MF or AML, both clinically and in blood tests, and when do you need a new bone marrow biopsy to check for this happening?”
Dr. Jeanne Palmer:
So, in terms of progression, there are several things that we see happen.
I think most importantly is, let’s say you have PV, and you’ve always been on medication, and it’s been hard to control. And all of a sudden, you don’t need medication to control it anymore, or the same thing for essential thrombocythemia. You have been taking medication, and all of a sudden your platelets go down, and you don’t need to take drugs anymore. A lot of times people are like, “Oh, that means I’m fixed and I’m well,” not necessarily, you really need to make sure to talk to your healthcare provider and potentially get a bone marrow biopsy.
Now, the other thing – sometimes the blood counts will actually drop too low, so you’ll have somebody who has PV, who has always been too high and then all of the sudden they come in, and their hemoglobin is very low, and they’re anemic, and that’s another situation where you do that. So, anytime the blood counts start to drop is concerning.
Now, it’s a continuum, so the blood counts may drop as you’re at the point of transitioning but it doesn’t – it’s not like if your blood count is dropping you say, “Oh my God, I have myelofibrosis, I need a bone marrow transplant tomorrow.” That’s not necessarily the case. This is generally a transition type process.
Also when the spleen starts to get enlarged. Now, the spleen can be enlarged even in the setting of just ET or just PV, so spleen enlargement does not necessarily mean you’re transforming, but it can be one of the things that we would see that would indicate that.
Dr. Jeanne Palmer:
And then finally white blood cell count increasing can often be a sign of that. Now, in terms of progression to AML, that is generally something we’ll see in the blood. AML or acute myeloid leukemia, is indicated by the presence of blasts at greater than 20 percent. Now, many patients with myelofibrosis, in particular, but even PV and ET, may have blasts in their peripheral blood. Blasts are normal. If I did a marrow on every healthy person out there, they are going to have some blasts, because these are the first part of the development of white blood cells. So, they’re like baby white blood cells. But what the problem is, is when they start to grow too much.
And so in the setting of myelofibrosis and even sometimes with these other diseases, the blasts will be in the peripheral blood primarily because the bone marrow is damaged and doesn’t hold them in very well. It becomes AML when it gets greater than 20 percent, so that blasts of greater than 20 percent in the peripheral blood or in the bone marrow but a lot of times we find it in the peripheral blood is where we indicate this has progressed to AML.
Dr. Jeanne Palmer:
Blasts of greater than 10 percent are also something that we really want to pay attention to, because that would suggest that the disease is starting to become more aggressive. Now, blasts vary, so for example, I’ve had patients go up to 11 and then drop back down to 3 or 4, and then they say around 3 or 4 or 5. So, you always want to make sure to double-check because one blast count at 11 percent, whereas it’s very important to address, may not necessarily reflect that you need to change in treatment at that time. Again, these blood tests, I always tell people, do not freak out over one blood test.
Make sure you get at least a couple of them to really confirm what you are looking at.