Clinical Features and Prognosis of MDS Patients with Chromosome 5 Abnormalities Other Than ‘5q-Syndrome’: Results of Multi-Center Analysis in Korea.

Introduction: The myelodysplastic syndrome (MDS) is frequently associated with various chromosomal abnormalities. ‘5q− syndrome’ is low-risk MDS known as good responder of lenalidomide recently. However, the patients with other abnormalities in chromosome 5 showed quite different clinical features from those with ‘5q− syndrome’. The aim of this study was a retrospective evaluation for Korean MDS patients with abnormalities in chromosome 5 other than ‘5q− syndrome’.

Materials and Methods: Among 456 patients with MDS diagnosed at 16 hospitals in Korea between 1996 and 2006, 370 with available cytogenetic data entered the study. Univariate and multivariate analysis were performed.

Results: Ninety three patients (25.1%) showed abnormalities in chromosome 5 and the ‘5q− syndorme’ was only 10 patients (2.7%). Among the rest, 39 patients (10.5%) had various abnormalities other than 5q deletion such as translocation or 5 monosomy, 38 (10.3%) had complex abnormalities with 5q−, and 2 had mosaic pattern with normal chromosome. Four patients had isolated 5q− but blasts in marrow were over 5%. The deletion of 5q was interstitial but with a predominance for 5q13-33 deletions (34.8%). MDS patients with chromosome 5 abnormalities other than ‘5q− syndrome’ didn’t share the clinical features with ‘5q− syndrome’. There was no leukemic transformation in ‘5q− syndrome’ group, but 18 (21.7%) with other abnormalities in chromosome 5 finally transformed to acute leukemia. Five year overall survival was significantly inferior in non-’5q− syndrome’ patients than ‘5q− syndrome’ (14.3% vs. 79.6%, P=0.0115).

Conclusions: Patients with isolated 5q− and excess blast (>5%), other abnormalities than isolated 5q−, or mosaic chromosome with isolated 5q− and normal chromosome didn’t share the clinical features such as lower rate of leukemic transformation and long survival.