Long-term survivors in myelodysplastic syndromes: clinical and biological characteristics.

Twenty-eight of 285 patients (9.8%) with primary myelodysplastic syndrome (MDS) survived more than 5 yr (long-term survivors). There were 21 females and 7 males, median age 60 yr (range 18-84 yr). None had circulating blasts, and 14 had refractory anemia (RA), 8 RA with ringed sideroblasts (RARS) and 6 RA with excess of blasts (RAEB). Thirty-seven percent of the 27 patients who were karyotyped had an abnormal clone, but none of them had -7/7q- or complex cytogenetic abnormalities. Only one of the 13 patients tested had abnormal (i.e., "leukemic") in vitro growth of GM progenitors. During 5 yr following the diagnosis, none of the 28 patients progressed to AML. Two patients with an initial diagnosis of RA showed progression to RAEB and CMML. After 5 yr, 23 of the 28 long-term survivors had stable disease (follow-up period ranged from 64 to 216 mo). One patient progressed to AML (113 mo after diagnosis) and another to RAEBT (80 mo after diagnosis). Eight asymptomatic patients were not treated and 12 patients received only supportive therapy. Except for 6 of 8 treated patients who responded to low-dose Ara-C, danazol, androgens, or immunosuppressive treatment, prolonged survival seemed to result mainly from the natural course of the disease. Except for Valensia score (p=0.033), other scoring systems (Bournemouth, Dusseldorf, Lille, and IPSS score) proved of relatively limited value in differentiating between intermediate (2-5 yr) and long-term survivors.