In this study, we investigated the incidence and prognostic impact of monosomal karyotype (MK) in 405 higher-risk Myelodysplastic Syndromes (MDS) patients treated with 5-AZA. The MK was present in 66 out of 405 (16.3%) patients, most of whom had complex karyotype (CK). MK was strongly associated with CK and the cytogenetic risk defined according to IPSS-R, as well as with high-risk disease, according to IPSS (P = .029), IPSS-R (P < .001), and WPSS (P < .001) classification systems. The overall response rate (ORR) was not different between MK+ and MK- patients (46.6% vs. 46.2%). At 28 months median follow-up, the median duration of response was 11 months in the entire cohort, 9.5 months in MK+ patients and 11 months in MK-patients (P = .024). The estimated median time to transformation to acute myeloid leukemia for MK+ patients was 17 months vs. 23 months for MK- patients (P = .025). The estimated median OS for MK+ patients was 12 months vs. 18 months for MK- patients (P < .001). Multivariate Cox regression analysis revealed that performance status (P < .001), IPSS-R (P < .001), and MK (P = .002) were independently associated with overall survival (OS). In a subgroup consisting of high and very-high risk patients according to IPSS-R, MK- patients showed better OS rates compared to MK+ patients (estimated median OS: 17 months vs. 12 months, P = .002). In conclusion, we found that MK is associated with reduced OS in patients with higher-risk MDS treated with 5-AZA. Furthermore, we showed that in MDS with high or very-high IPSS-R risk score, MK can further distinguish patients with worse outcome.
© 2018 Wiley Periodicals, Inc.