ESSENTIAL THROMBOCYTHAEMIA:PROGNOSTIC FACTORS IN THE ITALIANSERIES OF TWO THOUSAND PATIENTS

A series of 2139 patients with diagnosis of Essential Thrombocythaemia (ET), done between 1976 and 1996 in 60 Haematological Centers of GIMMC and verified according to PVSG criteria, have been retrospectively evaluated mainly to define the prognostic factors. The patients, 1315 females and 824 males, with median age 59 years (21% under 40 and 23% over 70 years), at diagnosis had a median platelet count of 910x109/ L (25% <750 and 20% >1200), splenomegaly (21%), hepatomegaly (25%), peripheral granulocyte precursors (8%), functional symptoms (35%), thrombotic risk factors (40%), haemorrhage (5%) and thrombosis(15%). The follow-up was 5.2 ±3.1 years (median 4.4). The treatment was: antiplatelet drugs 78% (ASA 49%), cytostatic drugs 82%, (alkylating molecules 38%, HU 48%, IFN a 22%, Anagrelide 2%).During the follow-up the platelet count (109/L was <400, 400 - 500 and 500 600 in 5%, 8% and 26% of cases respectively. Thesurvival curve was the same compared to the general Italian population in the first 10 years of follow-up but later it was appreciably lower mainly because of cancer mortality. The lethal events, censored at 15th year from diagnosis, were 203. Reported as events /100 patient-years deaths were: haemorrhage 0,1%, thrombosis 0,7%, haematological cancer 0,5% and other causes 0,6%. Respect the end-point exitus favourable prognostic factors resulted to be the female sex, (RR 0.6) and the antiplatelet treatment (RR 06), while resulted unfavourable the older age at diagnosis (40 60 years RR 3.5; 61- 70 years RR. 9.6; >70 years RR 25.2), the thrombosis at onset (RR 1.5), the peripheral granulocyte precursors (RR 1.8), the platelet count during the follow up >1000x109/L (RR 2.1). The role of antiplatelet and cytostaticdrugs (type, dose, duration) will be furtherly described.