Myelodysplastic Syndrome Patients Younger Than 50 Years: Epidemiological Data and Clinical Features

Abstract 4976

Less than 10% of patients with myelodysplastic syndromes (MDS) are younger than 50 years. It is yet unknown the exact role of prognostic scoring systems in this subset, because clinical relevant data were derived from large series of elderly patients. Undefined are also the clinical features of younger patients exposed to potential mutagens due to occupational reasons. Aim of our study was to report and analyze one of the largest series of young MDS, in terms of prognosis and overall survival. Ninety-one patients with MDS aged less than 50 years consecutively diagnosed and conservatively treated form July 1983 and December 2009 are reported and compared with the whole population of elderly MDS patients. Median age at diagnosis was 44 years (range 21–50). Sex M/F ratio was 0.68. According to FAB criteria there were 56 patients with refractory anemia (RA), 3 with refractory anemia with ringed sideroblasts (RARS), 22 with refractory anemia with excess of blasts (RAEB), 5 with refractory anemia with excess of blasts in transformation (RAEB-t) and 5 with chronic myelomonocytic leukemia (CMML). Revised 2008 WHO classification reclassified low risk patients as pure RA (only 8 patients), refractory unilineage cytopenia (RCUD, refractory thrombocytopenia, 2 patients) and refractory cytopenia with multilineage dysplasia (RCMD, 45 patients). RAEB patients were classified as RAEB-1 (11 patients) and RAEB-2 (11 patients). Eighty-five patients had evaluable cytogenetic analysis: the most frequent karyotypic change was trisomy 8 (10.5%), followed by monosomy 7 (5%). Among this cohort, 23 patients had occupational exposure to potential mutagens (more frequently benzene and its derivates and solvents): in the exposed group there was a male predominance (16/7), a higher frequency of RCMD (52%) and a higher frequency of monosomy 7 (13%). At a median follow-up of 72 months, 22 patients (24 %) evolved to acute leukemia: among the exposed cohort, a higher frequency of AML evolution was observed (39% vs 19% of non-exposed). IPSS categorization showed 30 patients as low risk, 35 patients as intermediate-1, 14 patients as intermediate-2 and 4 patients as high risk, with intermediate-1 risk being the more commonly detected. Both the intermediate-2 and high risk according to IPSS, together with age cut-off above 40 years, male sex, FAB and WHO high-risk definition and exposure to carcinogens during lifetime, were found to be predictive of a shorter overall survival. Comparison of younger patients with elderly MDS population followed in the same Institute over the same period of time, showed statistical differences in survival (88 months for younger vs 24 months for elderly MDS, p<0.0001), sex ratio (p=0.002), FAB and WHO classification (both p=0.03). These results suggest that MDS in patients aged less than 50 years could be identified as a distinct category and that aggressive approaches should rarely be recommended for younger patients belonging to the low and intermediate-I risk groups.