Long-term survivors in myelodysplastic syndromes: a report on 63 cases and comparison with short and intermediate survivors.

Sixty-three of 373 patients (17%) with de novo myelodysplastic syndrome (MDS) survived more than 5 yr (long survivors). At diagnosis, they usually had no or only moderate cytopenias; 63% of them had marrow blasts < 5%; only 1 patient had circulating blasts; 60% had refractory anaemia (RA) or refractory anaemia with ringed sideroblasts (RARS); 19% of the 43 patients who were karyotyped had an abnormal clone, and only 2 patients had complex cytogenetic findings. Only 4 of the 63 patients progressed to another FAB type within 5 yr of diagnosis, from RA to refractory anaemia with excess of blasts (RAEB) or chronic myelomonocytic leukaemia (CMML). After 5 yr, 9 patients showed progression (including progression to AML in 5 patients). The other patients remained stable (43 cases) or died from cytopenias or unrelated disorders (11 cases). Except for 3 patients who achieved prolonged complete remission with intensive chemotherapy, and possibly 3 patients who responded to low dose Ara C, prolonged survival seemed to result mainly from the low natural course of the disease. Although, as expected, significant differences for age, cytopenias, circulating and bone marrow blasts, and karyotype were seen between short (< 2 yr) and long (> 5 yr) very few significant differences were seen between intermediate and long survivors. These 2 subgroups only differed by significantly lower age and higher haemoglobin level in long survivors. Multivariate scoring systems (Bournemouth, Sanz's and Lille scores) proved of relatively limited value in differentiating them.(ABSTRACT TRUNCATED AT 250 WORDS)