What should you know about your MPN test results? Dr. Mascarenhas discusses how test results are used, including the importance of genetic mutations and risk stratification when analyzing results.
Dr. John Mascarenhas is Associate Professor of Medicine at the Icahn School of Medicine at Mount Sinai (ISMMS) and the Director of the Adult Leukemia Program and Leader of Clinical Investigation within the Myeloproliferative Disorders Program at Mount Sinai. Learn more about Dr. Mascarenhas, here.
Some patients may not know if they’ve received these important tests. So, what key questions should they ask their physician about testing?
Well, I think it’s important that the patients feel empowered to understand sort of where the field is and what key questions you would ask a physician, hematologist who’s taking care of you. So, I think all patients should be aware of their diagnosis, the name of the diagnosis, the subtype, but also do they have any of the key driving mutations, the JAK2 mutation, the calreticulin mutation, the MPL mutation, and that’s usually done off of a bone marrow biopsy sample, but it can be done off peripheral blood. And, they may not always know that it’s done. So, I think having a discussion with the position to understand there are criteria that exist called the World Health Organization criteria that are updated frequently and should set a standard throughout the world of how you diagnose and establish these diagnoses.
So, I think it’s important for physicians to be able to convey to the patients with confidence, “We follow these criteria and you have these criteria and we’ve done this testing that shows that you have these mutations.” And not just regurgitate what they found, but help them understand and navigate with that means, which again, I will point out that sometimes we don’t know. But, I think it’s important for physicians to convey sometimes that some of the findings that they may see, for example, patients look on portals these days and they can look at their labs and stuff like that. And, we don’t always have a terrific answer or an informed answer for everything that we get back. And, we will potentially in 10 years from now, but sometimes at the moment, we don’t. But, I think a discussion about the meaning of the labs that are obtained is probably good for the patient to understand what’s being done.
Absolutely. It sounds like each person’s situation is unique and should be considered before making any treatment choices. Can you talk about how the results of these tests may affect prognosis and treatment?
So, we do have risk stratification systems that we use for essential thrombocythemia, polycythemia vera, and myelofibrosis. I’ll talk about myelofibrosis because that’s probably a little bit more of a complex and sophisticated model. It’s also changing, and we update it frequently. And, these models are imperfect, so I always warn patients to not put all of their money in one basket when we talk about risk stratification. They broadly help us understand where a patient is in their disease course. So, for example, in myelofibrosis, historically, the DIPSS, the Dynamic International Prognostic Scoring System is used, which considered five clinical variables that have been shown to be independently prognostic. So, at age over 65, the presence of blasts or circulating immature cells in the peripheral blood, anemia, hemoglobin less than 10, symptoms, fevers, night sweats, weight loss or a high white count over 25,000, you those points up.
And patients can do this online. There are calculators that you can calculate your DIPSS score. And, you’ll see that there are four different risk groups that range from low risk to high risk, and they are associated with median survivals. We now know that mutations influence those, have influence on prognosis. So, there are a group of high molecular risk mutations like ASXL1, SRSF2, IDH1/2. So, there are mutations that also have prognostic significance, and we incorporate them into the decision-making.
And, essentially, and this is where I think patients have to be very careful, physicians have to be very careful with conveying this. With these risk models whether they are clinical variable risk models or these integrated molecular risk models, each category is associated with a median survival, that’s based on retrospective studies. But that doesn’t tell the patient specifically what they should expect in terms of survival. And, I always fear that patients, when they look at these things, or even physicians when they convey them that they may inadvertently misrepresent or convey what those really mean.
And, I think the purpose of those risk stratifications is really to help guide a risk adapted treatment approach that’s reasonable and is weighted for benefit to risk of the disease. So, for example, if you have advanced disease with a high-risk score of intermediate to or higher, bone marrow transplant in certain patients may be a warranted therapy to consider. So, they really help inform treatment.