What are the essential tests that should follow a myelofibrosis diagnosis? Dr. Joseph Scandura reviews the necessary laboratory testing, along with a discussion of next generation sequencing, and explains how often bone marrow biopsies should take place.
Dr. Joseph Scandura is Associate Professor of Medicine and Scientific Director of the Silver MPN Center at Weill Cornell Medicine. Learn more about Dr. Scandura, here.
What testing should take place following a myelofibrosis diagnosis?
So, a diagnosis of myelofibrosis always comes after a bone marrow exam and a physical examination. Often, patients have an enlarged spleen and blood count testing and a variety of other laboratory tests. So, after that and a diagnosis is made of myelofibrosis and, sort of, coincident with the diagnosis, we often look for molecular markers of myelofibrosis. So, these are malignancies of the bone marrow, cancers, if you will, on the bone marrow, although the term is scarier than or is different than what we think of for many malignancies in how it acts. But the myelofibrosis, this is a disease that’s characterized by, really, mutations in the malignant cells, the abnormal cells.
They’re really just one of three genes. And so, JAK2 being one of the genes, calreticulin or CALR being another one, and MPL one.
And more than 90 percent are people having mutation in just one of those three genes. And so, often at the time of diagnosis, tests for those mutations are done, and they help eliminate the possibilities of other causes of myelofibrosis – infections, rheumatological diseases. Sometimes, you can have marrow fibrosis but they don’t go along with mutations and the same clinical situation. And so, at the time of diagnosis, we usually know something about a mutation in JAK2, CALR, or MPL.
More commonly now, and it’s increasingly common over the past 10 years in, I would say, in New York City and many places across the country, we also look more broadly for other common mutations in the MPN cells. And these are what we refer in the batch as next generation sequencing or NGS panels, and we use the term panels because we’re looking at from a few tens to even 100 or a couple hundred genes for mutations that occur far less frequently than in JAK2 or MPL or CALR.
But they occur often enough that some of them we use to help guide treatment decision-making or approach to therapy. The reality of it is that that the technology to sequence and identify mutations has really outstripped our knowledge of what to do with all of that information.
And, for the vast majority of people, it comes down to do you have a marker, a genetic marker that tends to go along with higher risk, meaning a higher likelihood of something that we don’t want to have happen. And in that instance, although it may be looking at a hundred or so genes, it comes down to a binary thing – either you have or you don’t have.
Is there any other testing that you usually want to do?
Laboratory testing, for sure and, as I mentioned before, a bone marrow exam. But physical examination, some people might do imaging of the spleen size. Honestly, I don’t routinely do that outside of the setting of the clinical trial. I don’t really think it dictates therapy very often.
And if the spleen is so small that you can’t feel it on physical exam, it probably isn’t clinically meaningful anyway in terms of something to treat. It might be there, but it doesn’t really change things too much.
How often should patients have a bone marrow biopsy?
So, I’ll answer there is no standard in terms of monitoring for myelofibrosis with the marrow or otherwise. My personal approach is I do a marrow when I think it’s going to help medical decision-making. And so, for a patient who’s got early myelofibrosis, who’s been very stable, responding well to therapy, that could be three, five years between marrow exams.
For somebody who’s being considered for a clinical trial, oftentimes, a marrow exam is required before they start on the clinical trial and at various intervals afterwards. If there’s somebody who had been stable and something is changing, like the blood counts are changing or his symptoms are changing, or any of a number of clinical features, then I might look in the marrow to see what’s happening there, to see if explains and can help guide a treatment approach to help people feel better. So, there is no single standard, but my personal approach is to do a bone marrow exam when I think it’s going to help make a decision.