MYELOFIBROSIS WITH MYELOID METAPLASIA IN YOUNG INDIVIDUALS - DISEASE CHARACTERISTICS, PROGNOSTIC FACTORS AND IDENTIFICATION OF RISK GROUPS

Myelofibrosis with myeloid metaplasia (MMM) is an uncommon disorder in young individuals, for whom haemopoietic stem cell transplantation of fers the only possibility of cure. However, although the latter proced ure is associated with significant morbidity and mortality, the clinic al course of MMM is variable, with some patients surviving for less th an a year and others showing an indolent course. Selection of young MM M patients for transplantation or other newer therapies is currently d ifficult since no prognostic data exists for this subgroup. In the pre sent collaborative study a number of initial clinical and laboratory p arameters have been evaluated for prognosis in 121 MMM patients aged 5 5 years or less. Median survival of the series was 128 months (95% CT 90-172). In the Cox proportional hazard regression model three initial variables were independently associated with shorter survival: Hb <10 g/dl (P < 0.0001), the presence of constitutional symptoms (fever, sw eats, weight loss) (P = 0.001), and circulating blasts greater than or equal to 1% (P = 0.003). Based an the above three criteria, of the 11 6 patients with complete data, two groups were identified: a 'low-risk ' group, characterized by 88 patients with up to one adverse prognosti c factor, in whom MMM had an indolent course (median survival 176 mont hs, 95% CI 130-188), and a 'high-risk' group, including 28 patients wi th two or three factors, who had a more aggressive disease (median sur vival 33 months, 95% CI 20-42). The above prognostic scoring system sh owed a high positive predictive value, sensitivity and specificity to predict survival in the series, and could be of help in making treatme nt decisions in young patients with MMM.