Kaplan-Meier survival curves stratified by ICSS in subgroups of patients with lower and higher IPSS-R. Outcome of the 307 patients who had cytogenetic data at diagnosis (thus, IRSS-R could be calculated). (A) LFS and (B) OS of patients from the IPSS-R lower-risk group. (C) LFS and (D) OS of patients from the IPSS-R higher-risk group. Patients with high-risk ICSS had the worst prognosis, whereas those with low-risk ICSS had the best outcome among the 3 subgroups across IPSS-R.