New investigational strategies in patients with myelodysplastic syndromes

Therapeutic decisions in myelodysplastic syndromes (MDS) are complex owing to the gradual realization that not all patients with MDS have an indolent course. MDS is recognized as a heterogeneous group of disorders with different natural histories and is generally classified using the French-American-British (FAB) classification scheme (1) or the more recent International Prognostic Scoring System (IPSS) (2). Low-risk patients, as classified according to the FAB system, are those with refractory anemia (RA) or RA with ringed sideroblasts (RARS) or those classified according to the IPSS as being in the low or intermediate-1 risk groups. High-risk patients are those having RA with excess blasts in transformation (RAEB-t by FAB classification) or those in the high-risk group (IPSS). Categorization of patients having RA with excess blasts (RAEB by FAB classification) or those in the intermediate-2 risk group (IPSS) may depend on whether the categorization is at diagnosis (low risk) or is following referral to a tertiarycare center, with initial therapy having failed (high risk) (3) (Table 1). For the practical purposes of this review regarding investigational options, low-risk MDS patients are generally those with less than 10% blasts while high-risk MDS patients are those with more than 10% blasts. As the percentage of marrow blasts 400 Garcia-Manero and Kantarjian Table 1 Differences in Median Survival When MDS Patients Are Classified at Diagnosis Versus at a Tertiary Care Center MDS patients classified MDS patients classified at at a tertiary care centerb diagnosisa (n 816) (n 219) Median survival Median survival IPSS risk group % of total (years) % of total (years) Low 33 5.7 13 2.1 Intermediate-1 38 3.5 41 1.2 Intermediate-2 22 1.2 30 0.7 High 7 0.4 16 0.4 a Data of untreated patients from which the IPSS was developed (2). b Patient data from the M.D. Anderson Cancer Center (3). MDS, myelodysplastic syndromes; N, number; IPSS, International Prognostic Scoring System.