Validation of Updated Cytogenetic Risk Classification in Patients with Myelodysplastic Syndrome: Retrospective Study at Single Institution.

The International Prognostic Scoring System (IPSS) or the WHO Classification-Based Prognostic Scoring System (WPSS) are considered as gold standard to evaluate the patients with MDS in terms of their clinical courses. Recently, a new prognostic cytogenetic risk classification, defined as favorable (5q-, 12p-, 20q-, +21, -Y, 11q-, t(11)(q23), normal, 2 abnormalities including 5q-), intermediate-1 (+1q, 3q21/q26-abnormalities, +8, t(7q), +19, -21, any other single, any other double), intermediate-2 (-X, -7/7q-, 2 abnormalities incl. -7/7q-, complex = 3 abnormalities) or unfavorable risk group (Complex >3 abnormalities), has been reported through 3 large, well-characterized international investigations (German-Austrian (GA), Spanish MDS-registry, IMRAW). This new cytogenetic classification system showed better discrimination of patients according to their prognosis with respect to overall survival and leukemic transformation. The current study attempted to evaluate the new prognostic cytogenetic risk classification in patients with MDS, retrospectively.

Between 1996 and 2007, 180 patients with MDS, who were diagnosed and treated at the Samsung medical center, Seoul, Korea, were enrolled into the study. One hundred seventy one patients were analyzed, 115 patients receiving best supportive care were included in the present analysis. Clinical characteristics were as follows; age 59 years (median, range 16-83), male 72%; 3 patients (pts) has 5q-; 1 patient (pt), 12p-; 3 pts, 20q-; 5 pts, -Y; 1 pt, 11q-; 1 pt, t(11)(q23); 80 pts, normal; 2 pts, 2 abnormalities including 5q-; 1 pt, +1q; 1 pt, 3q21/q26-abnormalities; 18 pt, +8; 16 pts, any other single; 19 pts, any other double; 2 pts, -7/7q-; 6 pts, complex = 3 abnormalities; 12 pts, complex >3 abnormalities.

According to IPSS, 10 patients (9%) were at low risk, 77 patients (67%) at intermediate-1 (Int-1) risk, 22 patients (19%) at intermediate-2 (Int-2) risk and 6 patients (5%) at high risk. According to WPSS, 10 patients (9%) were at very low, 25 patients (22%) at low, 36 patients (31%) at intermediate, 31 patients(27%) at high and 13 patients(11%) at very high risk group. According to new cytogenetic risk classification, 66 patients (57%) were at favorable, 34 patients (30%) at intermediate-1 (Int-1), 9 patients (8%) at intermediate-2 (Int-2) and 6 patients (5%) at unfavorable subgroup. The median OS in overall population was 23.2 months. According to the IPSS, median OS in the Low, Int-1, Int-2 and High subgroup was 37.8, 27.5, 14.8 and 11.6 months, respectively (p<0.001). According to the WPSS, median OS in the subgroup of Very low, Low, Intermediate, High and Very high risk was 54.6, 43.1, 27.5, 16.5 and 11.9 months, respectively (p<0.001). By the new cytogenetic risk classification, median OS in the Favorable, Int-1, Int-2 and Unfavorable subgroup was 23.8, 24.1, 13.0 and 9.1 months (p=0.035). Sixteen cases (13.9%) showed documented leukemic evolutions with median 9.2 months of onset. It was difficult to analyze of leukemic evolution risk due to small number of sample size.

In the present study, the new cytogenetic risk classification does not seem to be validated retrospective series of patients, we couldn't validate that the new cytogenetic subgroups are powerful predictor of prognosis as good as IPSS or WPSS. To warrant availability of the new cytogenetic risk classification, large data sets should be necessary. Also, we should be consider review about the prognostic impact of the karyotype in MDS.

No relevant conflicts of interest to declare.