Improvement of criteria for refractory cytopenia with multilineage dysplasia according to the WHO classification based on prognostic significance of morphological features in patients with refractory anemia according to the FAB classification

In the criteria of refractory cytopenia with multilineage dysplasia (RCMD) according to the WHO (World Health Organization) classification, the frequency threshold concerning dysplasia of each lineage was defined as 10%. To predict overall survival (OS) and leukemia-free survival (LFS) for patients with refractory anemia (RA) according to the French-American-British (FAB) classification, we investigated prognostic factors based on the morphological features of 100 Japanese and 87 German FAB-RA patients, excluding 5q-syndrome. In the univariate analysis of all patients, pseudo-Pelger-Huet anomalies >= 10% (Pelger+), micromegakaryocytes >= 10% (mMgk+), dysgranulopoiesis (dys G) > 10% and dysmegakaryopoiesis (dys Mgk) >= 40% were unfavorable prognostic factors for OS and LFS (OS; P < 0.001, LFS; P < 0.001). The prognostic effects of the morphological features were similar in both Japanese and German patients. However, dys Mgk >= 10% was not correlated with OS and LFS. In the multivariate analysis, mMgk+ and dys Mgk >= 40% were adverse prognostic factors for OS for all patients, and dys G >= 10% and dys Mgk >= 40% were adverse prognostic factors for LFS for all patients. On the basis of the present analysis, we propose the following modified morphological criteria for RCMD. Modified RCMD should be defined as FAB-RA, excluding 5q-syndrome with dys G >= 10%, dys Mgk >= 40% or mMgk+.