Prognostic value of trisomy 8 in primary myelodysplastic syndrome

Background: According to the International Prognostic Scoring System (IPSS), sole +8 is categorized as intermediate cytogenetic subgroup. But as some myelodysplastic syndrome (MDS) patients with +8 perhaps progress quickly to acute leukaemia and have shorter survival, some reports have suggested that +8 should be categorized into poor risk cytogenetic group. The aim of this study was to clarify the prognostic role of +8 in MDS patients by comparing patients with normal karyotype, 20q- and -7/7q-.

Methods: The consecutive samples of 435 MDS patients in Shanghai were collected by prospective methods and diagnosed according to World Health Organization classification. Cytogenetic analysis was performed using conventional G-banding karyotyping and fluorescence in situ hybridization techniques. Prognosis was estimated by univariate Log-rank method and multivariate Cox proportional hazard models.

Results: Of 424 cases completing the cytogenetic analysis, 71 (16.7%) had +8, including 38 patients with sole +8 (9.0%). No significant difference in median survival was observed between patients with sole +8 and that with +8 and one of other abnormalities. The +8 clone size was not linked to survival. The median survival of patients with +8, normal karyotype and complex karyotype was 25months, 38.1months and 5.9months respectively. However, no significant difference was observed between patients with 20q- (21.4months) and -7/7q- (25.8months). Trisomy 8 was an independent prognostic factor by Cox regression model.

Conclusion: There is no significant difference in prognosis between patients with +8 and patients with 20q- or -7/7q-. Trisomy 8, 20q- and -7/7q- are categorized as intermediate cytogenetic risk according to our primary study.