What age group is essential thrombocytosis?

Oct 17, 2025 3 min read •

Oncology Hematology Myeloproliferative Neoplasms

While the median age for diagnosis is over 60, essential thrombocytosis (ET) can occur at any stage of life, with a notable, smaller incidence peak occurring in younger women. Understanding what age group is essential thrombocytosis most prevalent in is crucial for risk stratification and management, as age is a key factor in determining treatment strategies.

Quick Summary

Essential thrombocytosis primarily affects older adults, with the median age at diagnosis being around 60-65, but it can also be seen in younger adults, particularly women. Risk stratification and treatment strategies are heavily influenced by the patient's age and other clinical factors.

Key Points

Age has a dual incidence peak: Essential thrombocytosis is most common in individuals over 60, but it also has a smaller, second peak in incidence in younger adults, particularly women.
Older age increases thrombosis risk: Patients aged 60 and older are considered high-risk for blood clots (thrombosis), and age is a critical factor in risk stratification.
Younger patients have a better prognosis: Those diagnosed before age 60 generally have a longer median survival and fewer complications, though careful monitoring is still necessary.
Gender differences exist: ET is diagnosed more often in women than in men, with a notable prevalence in younger women.
Genetic markers vary by age: The JAK2 mutation is more frequent in older ET patients, while the CALR mutation and triple-negative status are more commonly associated with younger patients.
Risk stratification is key to treatment: Clinical management, from observation to therapies aimed at reducing platelet count, is determined by a risk assessment that incorporates age, prior thrombotic events, and genetic mutations.

Essential thrombocytosis (ET), a chronic blood disorder, has a bimodal age distribution, meaning it presents with two peaks in incidence across different age groups. The first, and smaller, peak is observed in younger adults, predominantly women in their 30s and 40s. The second, and more significant, peak occurs in older adults, typically over the age of 60, where the disease incidence is higher. This dual-peaked distribution means that while it is more common in seniors, ET is not exclusively a disease of the elderly.

The Bimodal Age Distribution of Essential Thrombocytosis

Incidence in Older Adults

The majority of essential thrombocytosis cases are diagnosed in individuals over 60 years of age, with some studies citing a median age at diagnosis of 60 to 65. The risk of complications, particularly thrombotic events (blood clots), is higher in this age group. For older patients, age is a primary factor in risk assessment and often leads to therapies aimed at lowering platelet count. Control of cardiovascular risk factors like hypertension and diabetes is also critical for this group to manage overall risk.

Incidence in Younger Adults

Despite the higher overall incidence in seniors, a significant portion of ET patients are diagnosed before age 40. Among younger individuals, the disease is more prevalent in women than in men, with a female-to-male ratio of about 2:1. Younger patients, particularly those under 40 with no history of thrombosis, are often classified into a very low-risk category. While the prognosis for younger patients is generally more favorable, they still require careful management, especially during pregnancy, where the risk of complications is increased.

Genetic Mutations and Age

Research has identified several genetic mutations associated with ET, which can vary in prevalence across different age groups and influence prognosis.

JAK2 V617F Mutation: Found in approximately half of all ET patients, this mutation is associated with a higher risk of clotting and is more common in older patients.
CALR Mutation: Occurs in about 20-25% of ET patients and is more frequently seen in younger individuals and those with a lower-risk profile. CALR-positive patients generally have a better prognosis compared to those with the JAK2 mutation.
Triple Negative: A subset of patients, particularly among younger cohorts, tests negative for the JAK2, CALR, and MPL mutations. Their disease may have a different, potentially more benign, clinical course.

Essential Thrombocytosis: Age and Risk Stratification

The International Prognostic Score for Essential Thrombocythemia (IPSET) is a system used to categorize patients into low, intermediate, and high-risk groups based on factors that include age and prior thrombotic events.


Feature	Low-Risk Patient	High-Risk Patient
Age	Younger than 60 years	60 years or older
Prior Thrombosis	No history of blood clots	Previous history of blood clots
JAK2 Mutation	Unmutated	JAK2-mutated
Treatment Focus	Observation, managing symptoms	Therapies to reduce platelet count, managing symptoms
Genetic Profile	More likely to have CALR or be triple-negative	More likely to have JAK2 mutation

This table highlights the significant role age plays in guiding treatment decisions and risk management for ET patients.

Symptom Presentation Across Different Age Groups

While many ET patients, especially younger ones, may be asymptomatic, symptoms can vary depending on age. Older patients are more likely to present with symptoms related to blood clots, such as transient ischemic attacks (TIAs), stroke, or heart attacks. In contrast, a small number of younger patients may experience vasomotor symptoms like headaches, dizziness, or erythromelalgia (burning pain and redness in the hands and feet). Younger women, in particular, may first be diagnosed during a workup for recurrent pregnancy loss, which is a known complication.

Conclusion

In summary, essential thrombocytosis does not affect a single age group but has two peaks of incidence, making it a disease that spans the adult lifespan. The higher overall incidence in older adults over 60, combined with a notable, albeit smaller, peak in younger women, shapes the clinical approach to this disorder. A patient's age is one of the most critical factors used to determine risk and personalize treatment strategies, along with their genetic mutation status and history of vascular events. Younger patients often have a better prognosis and may require less aggressive treatment, while older patients with additional risk factors typically require active management to prevent life-threatening complications. For more detailed information, the MPN Research Foundation provides comprehensive resources on this and other myeloproliferative neoplasms.

Frequently Asked Questions

Essential thrombocytosis is most commonly diagnosed in older adults, with the median age of diagnosis typically falling between 60 and 65 years. However, it can also be diagnosed in younger individuals, and a smaller incidence peak is often observed in women under 40.

Essential thrombocytosis is more common in older adults over 60. That being said, it is known to have a bimodal distribution, with a smaller but still significant peak occurring in young women.

Yes, age significantly affects the risk of complications. Older patients (age 60 or older) are classified as high-risk for thrombotic events (blood clots). Younger patients with no prior history of blood clots are considered low-risk.

Yes, there is. While the incidence in older patients is similar between the sexes, essential thrombocytosis occurs more often in women than in men, particularly among the younger patient population.

No, their prognosis can differ. Younger patients typically have a more favorable prognosis, with a longer life expectancy compared to those diagnosed at an older age. This is often tied to a lower risk of thrombosis and different genetic mutation profiles.

Age is a key factor in guiding treatment. Low-risk patients, typically under 60 and with no history of thrombosis, may only need observation or supportive care. High-risk patients, including those over 60, usually receive therapies to reduce their platelet count.

Yes, certain mutations have different prevalences across age groups. The JAK2 mutation is more frequent in older ET patients, while the CALR mutation and triple-negative status are more commonly associated with younger patients.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.