The answer is "it depends." If you are low-risk ET with the JAK2 mutation, then the protocol is for aspirin-only. Note that for those with the CALR mutation who are low-risk, the recommendation is monitor-only.

High risk for ET is defined as age > 60/65, previous incident of thrombosis, significant symptoms such as TIA, or with higher PLT levels - Acquired von Willebrand Disease/ incidents of significant hemorrhage. In the absence of being in a high risk group, there is no reason to initiate cytoreductive therapy. For most of my 31 years with ET (which later progressed to PV) I was on an aspirin-only protocol. I have never had a single incident of thrombosis.

Do note that chemotherapy with hydroxyurea is only one of the treatment options when cytoreduction is indicated. The other first-line choice is Pegasys, which is an immune modulating therapy. There are also second line choices such as Jakafi and anagrelide. There are also treatments in clinical trial such as bomedemstat and Besremi.

It is also important to note that there is more to treating ET than reducing risk of thrombosis. The secondary or constitutional symptoms can often be the more significant issue.

Here are a few articles you my find of interest.
https://mpnjournal.org/how-i-treat-mpns-2/
https://www.legeforeningen.no/contentassets/dc7...

The presentations from the 2023 MPN Education Foundation are also quite informative.
https://mpninfo.org/conferences/2023-conference...

Wishing you all the best.

It sounds like your doc is taking a more flexible approach than to rigidly follow an age-based protocol. I certainly agree that we all age differently. My MPN Specialist told me "65 is the new 35." I like that doc. Given that you have the CALR mutation and no history of thrombosis, the risks of cytoreduction may outweigh the benefits in your case. Perhaps some of the newer treatment options such as the vaccine-based treatment for CALR will become available before too long. There are hopeful treatment options like Bomedemstat (LSD1-inhibitor) also in development.

Wishing you all the best.

I was diagnosed with ET about 10 months ago. I was told at the time that I should start taking Hydroxyurea, although my platelets were only in the upper 400’s! I did not concur, and found another hematologist. He recommended 2 low-dose aspirin a day. My platelets have since gone up, but still under 600,000, so I’m sticking with the aspirin for the time being. I’m relatively symptom-free and hate to start a drug unless I really need to.

You never have to start cytoreduction for asymptomatic ET unless you believe it is in your best interests to do so. There is a risk stratification system in place for ET. I believe your profile would match intermediate risk.

Most docs would recommend cytoreduction for anyone with ET age > 60/65, but not all. You are at lower risk if you have the CALR mutation. You will need to weigh the benefits of cytoreduction in your case against the intrinsic risks. If you decide on cytoreduction, there is more than one choice about what to use. Hydroxyurea, Pegasys, and anagrelide are all in common use. There are ET clinical trials for Besremi and Bomedemstat underway. You have a variety of choices.

There is a bit about risk stratification in this article and on the attached table.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC71...

Note - my MPN Specialist said "65 is the new 35." I like that doc!

All the best moving forward

Cici,

“Stick to your guns” as long as you can on the low-dose aspirin.