ET is characterized by1:
Erythromelalgia (burning or throbbing pain in the hands or feet)
Low-grade fever
Thrombus
Unexpected or exaggerated bleeding
Enlarged spleen
Weight loss
Night sweats
Chest pain
Some ET symptoms are associated with compromised cerebral blood flow1:
Headache
Dizziness
Weakness or numbness on one side of the body
Slurred speech
Blurred or double vision
Symptom burden affects a substantial percentage of patients2
Patients assessed symptom burden according to the MPN-SAF TSS2*
The vast majority of patients (87%) reported fatigue, and at least half reported early satiety, concentration problems, inactivity, abdominal discomfort, and night sweats2
*Symptom assessment of 594 patients with ET. Incidence is a score of >0 on the MPN-SAF TSS. Symptom severity was rated on a 0 (absent/as good as it can be) to 10 (worst imaginable/as bad as it can be) scale. The MPN-SAF TSS has a possible range of 0 to 100, with 100 representing the highest level of symptom severity. Fatigue was independently measured by coadministration of the Brief Fatigue Inventory.2
ET may be difficult to diagnose
Diagnosing ET may be difficult because of its similarity to other MPNs, and misdiagnosis can have an impact on patient outcomes.3,4
The IWG-MRT subjected 1104 cases of locally diagnosed ET to review by a central laboratory. The laboratory determined that 891 of the cases met the WHO criteria for ET, but 213 did not. They classified most of these cases as early/prefibrotic MF.3
Performing an accurate bone marrow biopsy for the differential diagnosis of ET from early/prefibrotic MF is important.
An IWG-MRT laboratory review determined that 19% (213/1104) of locally diagnosed cases of ET did not meet the WHO criteria3
Management of ET is multifaceted
The focus of managing ET is to5,6:
- Avoid first occurrence and/or recurrence of thrombotic and bleeding complications
- Minimize the risk of acute leukemia and post-polycythemia vera MF
- Control systemic symptoms
- Treat complications (thrombosis and hemorrhage)
- Manage risk situation (eg, pregnancy, surgery)
ET=essential thrombocythemia; IWG-MRT=International Working Group-Myeloproliferative Neoplasms Research and Treatment; MF=myelofibrosis; MPN=myeloproliferative neoplasm; MPN-SAF=Myeloproliferative Neoplasm Symptom Assessment Form; TSS=Total Symptom Score; WHO=World Health Organization.
References: 1. Leukemia & Lymphoma Society. Myeloproliferative neoplasms: in detail. https://www.lls.org/master/myeloproliferative-neoplasms-detail. Accessed May 21, 2025. 2. Emanuel RM, Dueck AC, Geyer HL, et al. Myeloproliferative neoplasm (MPN) symptom assessment form total symptom score: prospective international assessment of an abbreviated symptom burden scoring system among patients with MPNs. J Clin Oncol. 2012;30(33):4098-4103. 3. Barbui T, Thiele J, Passamonti F, et al. Survival and disease progression in essential thrombocythemia are significantly influenced by accurate morphologic diagnosis: an international study. J Clin Oncol. 2011;29(23):3179-3184. 4. Tefferi A, Vardiman JW. Classification and diagnosis of myeloproliferative neoplasms: the 2008 World Health Organization criteria and point-of-care diagnostic algorithms. Leukemia. 2008;22(1):14-22. 5. Barbui T, Barosi G, Birgegard G, et al. Philadelphia-negative classical myeloproliferative neoplasms: critical concepts and management recommendations from European LeukemiaNet. J Clin Oncol. 2011;29(6):761-770. 6. Beer PA, Green AR. Pathogenesis and management of essential thrombocythemia. Hematology Am Soc Hematol Educ Program. 2009:621-628.