Hydroxycarbamide and platelet count: is my experience so far typical?

[JaK2ET]

A few days ago I saw the Haematology Clinical Nurse Specialist (CNS) for the first review (at 5 weeks) of my recently started chemotherapy treatment for ET and raised platelets. Following the diagnosis of ET about a year ago I was initially on Aspirin 75mg EC etc but chemotherapy was added because the platelet count had climbed into the 900s by late 2019; I was put on Hydroxycarbamide (Hydroxyurea) 500mg 1 a day. Blood samples were taken at 2 weeks and 4+ weeks (a few days before the CNS appointment).

My CNS assured me that my white blood cell counts were adequate to fight off infection: I need not wear a protective mask when using public transport, visiting the hospital, etc or avoid social gatherings. The fact that I have had a bad cold and felt very rough for quite a bit of the last few weeks should be considered as purely a coincidence (and bad colds are doing the rounds at this time of year).

At 2 weeks the platelet count was down into the 600s, which seemed promising (it had been in the high 800s early in 2020) ... but at 4+ weeks the platelet count had gone over 1000, its highest ever level! I was of course very alarmed. I was told that the increase in platelets could be linked to the cold/virus infections. My CNS ordered my next lot of drugs, with a small increase in the Hydroxycarbamide dose: until the next review I should take 500mg 1 a day Mon to Sat but 2 a day on Sundays.

Is this experience typical? If the platelet count can fluctuate so much over a few weeks, how will it be possible to achieve just the right dosage of chemotherapy?

Many thanks in advance for feedback from more experienced ETers!

[lhammy66]

Yes. I have had something similar. I was put on antibiotics to help fight off a cold and it was still much worse than any cold I usually suffer. This was also at a point where they were still trying to get my bloods under control and the disease increased in intensity - it's a complex process where the counts can rise with the disease getting more active but also is affected by colds etc. It takes a while to get everything levelled off - in my case 7 months in we are only just beginning to stabilise the condition and the dose necessary.

[Applesnpears]

Platelet counts can vary significantly (+/- 10%) between samples, even if the samples are taken ten minutes apart. So if the " true" result is 900 you might get reported results of 810 to 990. In part this is because platelets have a habit of sticking together making it hard to get an accurate count.

So the standard advice is not to be too concerned about single results but to be looking at the trends over time.

Infections tend to increase platelet counts in all people but having an MPN and an infection makes it hard to disentangle what your MPN is doing.

Tweaking your medication based on blood test results is standard practice, especially in the early stages. It can be more complex if you start treatment in the winter months when seasonal infections make it tricky to spot trends and changes.

It sounds like you being closely monitored and are in good hands. Things should settle down as you recover from your cold/ flu.

[charl17]

I went quickly from 500 per day to alternating 500 and 1000 to 1000 per day. Comparing your experience to mine, it seems that your nurse is making a very small adjustment to a low dose. Perhaps, the CNS is being cautious.

Platelets do fluctuate and it takes a while to find the right dose of hydroxyurea. My advice is to let the professionals worry about your platelets (they can count them) and to focus on side effects and signs of toxicity. They may not be able to observe everything that is going on.

[Kauaiboy in reply to charl17]

What are the signs of toxicity?

[JaK2ET in reply to Kauaiboy]

They can include skin problems such as leg ulcers or skin cancer ...

[Osteomyelio]

My platelets have fluctuated too. A good Immunologist can assess your immune system capabilities and work in conjunction with your MPN specialist to help monitor your resistance to infections

[Ebot]

Hi there. Fluctuations are entirely normal especially as your haem team tries to get your counts under control. It’s a bit of trial and error and most will be cautious and tweak the Hydroxy dose. Infections can impact on the counts so just go with the flow. Your haem team seem on top of it and following standard protocols. All the best.