From our friends ay MyMPNTeam. The interview with Dr. Kuykendall is informative and easily understood. There is an article based on the interview too.
“This association between high platelets and thrombotic events has been looked at in a variety of fashions over the past 50 years now, and really nothing conclusive has come out of that,” reported Dr. Kuykendall. “In fact, large studies have shown really no correlation between higher platelet counts and an increased risk of thrombosis. If there’s anything that’s certain, it’s that if platelet counts get to maybe over a million or over 1.5 million, there’s an increased risk of bleeding that occurs.” mympnteam.com/resources/und...
The referenced journal article by Dr. Kuykendall in the Journal of the National Cancer Center Network , Sept. 2020 goes into more detail about the studies about platelet counts. Download the PDF. It is easier to read. jnccn.org/view/journals/jnc...
Very interesting data that bears on treatment decisions.
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hunter5582
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I am so confused by this information. I was told clearly that platelets in a high number poses a risk for thrombotic events. Isn't it just mincing words to say that it is the JAK2 mutation not the platelets themselves that put a person at risk of clots and strokes?
So when I accept treatment and then celebrate the normalization of my blood counts, it is a false promise if the JAK2 mutation is still working in my bone marrow?
Suggest you review your questions with a MPN Specialist who knows your case and can give you a case-specific answer.
In general, there is no evidence of a linear relationship between absolute platelet numbers and risk of thrombosis. There is no evidence of a value to making the platelet numbers look "normal" in terms of thrombosis risk. That is not to say that cytoreduction is never indicated. It is very important at very high levels of thrombocytosis to reduce risk of hemorrhage. It is also important for people with PV to control erythrocytosis. There is a linear relationship with erythrocytosis and thrombosis risk. While it is still being debated, there may well be a relationship between leukocytosis and thrombosis risk.
There is some evidence that the JAK2 mutation also causes an alteration in how the platelets interact with the vascular endothelium. There is more detail in the published articles on this topic. It is referenced in the interview as well. “Paresthesias are numbness and tingling and sensations typically occurring in the fingers and the toes,” he said. “A lot of times this has to do with platelet and blood vessel interactions that occur with essential thrombocythemia.” Platelets can also lead to other blood vessel problems. “I think with essential thrombocythemia what we see more commonly are headaches and some of these microvascular symptoms, to use a broad term. That would be like ringing in the ears, headaches, [and] fullness in the head.”
There is more to managing a MPN than reducing the absolute number of platelets. It is more complex than that. It is also about how the platelets behave and controlling all of the symptoms we may experience. A more complete understanding requires understanding hemostasis (coagulation cascade), hematopoiesis, and how the JAK-STAT pathway works.
If you would like to learn more, the webinars from the MPN Education Foundation are a very good place to start. You may find the presentations on Managing ET in 2023 and MPN Molecular Biology of particular interest. mpninfo.org/conferences/202...
MPN care is evolving. A lot of progress has been made in recent years. The understanding of how MPNs work and should be treated has improved. We are fortunate that our care is improving and that we have more options than ever before. There are excellent resources to learn more and stay on top of what is happening in the field. It is in our best interests to stay informed so that we can be more actively involved in setting goals and determining our treatment strategy.
I was fascinated by this. Twice my hematologist has let me stop taking HU…for at least a month because platelets were in the 500s and I take a blood thinner….and the headaches, ringing in the ears continued even off HU. I was just beginning to think it was ET JAK2 causing this and then just read your excerpts. I am now beginning to think I should ask about Pegasys because I think I read it helps lower JAK2 burden and platelets.
The understanding of thrombocytosis and the other aspects of the JAK2 mutation have improved greatly in recent years. Our treatment options have expanded as well.
You are correct that the interferons can lower JAK2 allele burden. The IFNs seem to more selectively target the mutated hematopoietic stem cells. In my case, the IFNs have lowered my JAk2 allele burden from 38% to 9% in 18 months. The IFNs (Pegasys/Besremi) have been more effective and easier to tolerate than HU or venesection-only.
We each respond differently to each of the treatment options. HU and PEG are both recognized as viable treatment options for ET/PV. In the absence of a medical contraindication, it is the patient's preference that should drive this decision. Dr. Harrison and other leading experts have published information on this choice.
hi Hunter, thanks for the article. This is the same information that I discovered on pubmed years ago and discussed with my haematologist, which he promptly ignored. He wanted me to start HU because one time my platelets were over 1500. That was his only reason, he never asked how I was feeling.
I then checked with an MPN specialist who was fine with my own personal regime of ½ aspirin every third day, due to risk of bleeding which I had also read about . No HU needed.
Haven’t been back to see my useless haem in over 2+years and feel so much happier not having any medical appointments. I just get on with living and enjoying life to the full.
I really do encourage people to do their own research and do question the so-called experts . If a dr recommends something, then please take the time to research that option before agreeing. Drugs.com is another great resource for checking all the side effects. I prefer the professional version which is more honest.
Sorry to hear about your negative experience with a hematologist. Unfortunately, you are not the only MPNer who has had this kind of experience. MPNs are rare disorders and many hematologists have little experience with them. They do not have the experience and knowledge to do anything other than follow the protocol they know. Individualized MPN care is not an option if the doctor does not have the ability to provide it.
I also use the drugs.com professional version as a resource. I also use epocrates.com and rxlist.com as primary sources. I never take anything without checking the medication risk/benefit profile and also checking for drug interactions. As you note, the resources that are intended for medical professionals are usually more informative.
I agree about doing your own research and asking questions. I have been blessed to have excellent MPN Specialists to follow my case. I also have a wonderful local hematologist who provides ongoing care. All of my docs do a great job listening, answering questions, and respecting my right to make informed decisions about my care. That is how all doctors should treat their patients.
Thank you for sharing this article Hunter. It’s very relevant to my current ET status, and in alignment with the many discussions shared with my MPN specialist. From my understanding, having the JAK2 mutation increases my risk of thrombotic events, even if my platelet levels were to fall within the normal range. My consideration of any future treatment will be focused on what the authors emphasize should be the goals of novel agents: disease modification, stem cell eradication, and molecular remission.
Thanks for this! Interesting read. I will just chime in and agree that bleeding (from the lowered "von Willebrandt" - or, as we call it in my family, "the duke" is an issue. Had very high platelets and experienced blood in urine, had my vW factors checked and one was lowered so I was put on medicine. I don't know why vW is not checked more routinely with super high platelets but it's probably a price issue.
I do not think that a von Willebrand Panel is all that expensive as blood tests go. About $500 retail for a full panel I believe. Less for just checking the vWB antigen. Typically it is covered by insurance (insurance usually does not pay full price). People with ET can experience deceased vWB factors without it rising to the level of acquired von Willebrand Disease. That did happen to me. I noticed increase bleeding/bruising anytime my PLT > 800.
W eused to check my vWB factors periodically. With my PLT so well controlled on Besremi, I no longer feel the need. Unfortunately, there are still docs who think that PLT need to be well above 1,000 before there is a need to check vWB factors. I would disagree based on my own experience and some of what is in the literature. I believe that checking on vWB factors should be a standard part of assessing the status of any patient with thrombocytosis. It is essential if the patient demonstrates an unusual level of hemorrhage,
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is an issue. Had very high platelets and experienced blood in urine, had my vW factors checked and one was lowered so I was put on medicine. I don't know why vW is not checked more routinely with super high platelets but it's probably a price issue.
Symptoms with platelet count ~500?
High platelet count and no answers 
variation in JAK 2 platelet count
High platelet count? Anagrelide? Hydroxyurea?
MF, platelet count and feeling anxious 
