Diagnosing ET and scoring your ET risks

Back in April, the Cleveland Clinic added some updated info in handy chart form that might be useful to ET patients, including the scoring system used by clinicians to determine your prognosis. For those new to ET, this info may help you understand what tests your doctor will order and what factors they look at when they assess your risks.

Here's the first chart:

Diagnostic criteria for essential thrombocythemia

Current (2008) WHO criteria	Proposed Criteria
Major criteria
Platelet count ≥450 x 109/L Megakaryocyte proliferation with large and mature morphology Not meeting WHO criteria for CML, PV, PMF, MDS or other myeloid neoplasm Demonstration of JAK2 V617F or other clonal marker or no evidence of reactive thrombocytosis	Platelet count ≥450 x 109/L Megakaryocyte proliferation with large and mature morphology Not meeting WHO criteria for CML, PV, PMF, MDS or other myeloid neoplasm Presence of JAK2, CALR, or MPL mutation
Minor criteria
	Presence of a clonal marker (eg, abnormal karyotype) or absence of evidence for reactive thrombocytosis
Requires all 4 major criteria	Requires all 4 major criteria OR first 3 major criteria and 1 minor criterion

CML = chronic myelogenous leukemia; ET = essential thrombocythemia; MDS = myelodysplastic syndrome; PMF = primary myelofibrosis; PV = polycythemia vera; WHO = World Health Organization.

Some background: Remember that the World Health Organization reclassified ET from a blood disorder to a cancer (neoplasm) back in 2006. My guess is that this reclassification was beneficial for most of us because it stimulated more research into ET and other myeloproliferative neoplasms. The chart above reflects the fact that in just seven years, MPL and CALR, have been identified as mutations associated with ET; only one (JAK2) was known in 2008.

More useful to you as an ET patient is that the chart above shows what your doctor is looking at to make your diagnosis. These are things that your doctor can determine from some blood tests, and, if needed a bone marrow biopsy. (My bone marrow biopsy was quick and generally painless. You can read about it below.)

Here's the second chart:

Essential thrombocythemia prognostic scoring system

Parameter	Points
Age ≥60 years	2
WBC count ≥11 x 109/L	1
History of thrombosis	1

Careful! The chart above is info I think that ET patients should use with care. The top part of the chart shows how your hematologist determines your risk group. But there seem to be some differences among individual doctors over how to assess risks. For example, my doc looks at overall general health--your real age rather than your chronological age, if you will--and doesn't see 60 as some kind of magic age. But the reason you get two points for being 60 is because the risk in the overall population for getting a blood clot goes up at that age.

So a good question to ask your doctor is this: What's my risk group and how do you figure that out?

Here's the third chart:

Total points	Risk group	Median survival, years
4	High	8.8
3	High	16.5
2	Intermediate	19.9
1	Intermediate	24.5
0	Low	Not Reached

CAUTION! The chart above correlates risk points with prognosis--that is how long you might live after the onset of ET. Remember that "median" does not mean "average." "Median" means that, of the patients studied, half were still alive after the given number of years. Also remember that this info includes all ET patients. It doesn't break down median survival rates by type of ET mutation, which is something that needs more study. Moreover, take into consideration that younger patients and those in good health may survive for decades after diagnosis.

A good question to ask your doctor when looking at this data is, "What can I do to improve my chances of staying as health as possible?"

A final word: You probably get sick of reading these caveats about taking all info with a grain of salt. But ET, while a serious chronic disease, is still fairly mysterious. Researchers are still studying us (and that's a good thing, like Martha Stewart says). Be informed, stay as healthy as you can, ask lots of questions.

Be well!

Related: Bone marrow biopsy washout?

Related: ... and I've got my brand spankin' new diagnosis!

Related: I've joined the CALR-positive club!

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