Researchers from Serbia and Poland developed and validated a predictive score for the differential diagnosis of prefibrotic primary myelofibrosis (MF) from essential thrombocythemia (ET), a study found. This score is clinically relevant since the prognoses and treatments of these 2 diseases are different.

Patients who have a score of 2 or more may have primary MF and should undergo hematological work-up “as soon as possible because there is a chance that some of these patients may have rapid disease progression and a shortened life expectancy,” the researchers noted.

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The study is published in the journal Cancers.

Prefibrotic primary MF and ET share similar phenotypes at presentation with thrombocytosis. The present study aimed to identify laboratory parameters that are clinically significant in differentiating the 2 conditions and to develop a predictive model to diagnose prefibrotic primary MF. 

The team retrospectively analyzed 464 patients. Of these, 289 had ET, while 175 had prefibrotic primary MF. 

Using data from a cohort of 229 patients, of whom 143 had ET and 86 had prefibrotic primary MF, they built a model. They then tested the internal validation cohort of 235 patients. This group consisted of 146 patients with ET and 89 patients with prefibrotic primary MF. 

The most important predictors of prefibrotic primary MF were 60 years of age or above, splenomegaly, and increased lactate dehydrogenase levels. 

When calculating risk scores, an age of 60 years or above and increased lactate dehydrogenase levels were assigned 1 point each and splenomegaly was given 2 points. 

The positive predictive value for a diagnosis of prefibrotic primary MF with a score of 2 or more points was 69.8% and with a score of 3 or more points was 88.2%. 

The diagnostic performance had similar values in the validation cohort. 

The new model could differentiate between ET and prefibrotic primary MF in patients with myeloproliferative neoplasms and thrombocytosis at presentation.


Lekovic D, Bogdanovic A, Sobas M, et al. Easily applicable predictive score for differential diagnosis of prefibrotic primary myelofibrosis from essential thrombocythemia. Cancers (Basel). Published online August 20, 2023. doi:10.3390/cancers15164180