Clinical Characteristics at Onset and Treatment Approaches in Young and Elderly Patients with Essential Thrombocitemia (ET) in Lazio Region: Evaluation of Retrospective and Prospective Databases

Background Essential Thrombocythemia (ET) is the most common Myeloproliferative Neoplasm (MPN): clinical features at diagnosis as well as treatment approaches are different between young and elderly patients (pts), with a worldwide accepted age cut-off of 60 years (yrs).

Aim To describe clinical features in a large regional cohort of young and elderly pts with ET, we evaluate all pts recorded in the retrospective and prospective databases of Latial Group for MPN study from January 2000 to December 2016.

Results A whole cohort of 1614 pts [median age 67.5 yrs, interquartile range (IQR) xx - xx] was analysed. Patients were divided into two groups; Group A with 622 pts aged < 60 yrs. and Group B with 992 pts aged ≥ 60 yrs. Median follow-up was 64 and 60 months, respectively. In both groups female sex was prevalent (63.2%). JAK-2 V617F positivity was 60% in young vs 69.7% in elderly pts, with a median allele burden < 20% (9.6% and 19.3%, respectively) and only few patients with ≥ 50% (3.5% and 1.0%, respectively). Spleen enlargement was reported in 15.8% vs 14.1% of pts (p=0.647), median leukocytes count (8.93 vs 8.75 x 10⁹/l) (p= 0. and median platelet count (702 vs 766 x 10⁹/l) were similar. Previous thrombotic events were reported more frequently in elderly (20.0%) than in young pts (12.2%) (p< 0.001), with a 2/3 ratio in favor of arterial events; however, previous splanchnic thromboses were more frequent in young pts. In the Table are reported cardio-vascular risk factors (CVF) (smoke, diabetes, hypertension, dyslipidaemia) and treatments: as expected, CVF were more frequent in elderly, with at least 1 CVF reported 79.5% in elderly vs 57.7% in young pts (p< 0.001). Antithrombotic treatment was administered in 93.1% of young and 95.8% of elderly (p=0.106): as expected, cytoreductive treatments were started in approximal all elderly pts (92.5%) compared to 57.2% of younger pts (p< 0.001).

Conclusions Real-life observation of a large cohort of unselected ET pts showed that 60 yrs. old pts are a different population in comparison to younger with high allele burden of JAK-2, more previous thrombosis and CV-RFs. These findings involve a different clinical approach.

Table 1 - Cardiovascular risk factors and treatment approaches in ET patients according to age

Abruzzese:BMS, Incyte, Novartis, Pfizer: Consultancy. Rossi:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.