Abstract:

Objective To assess the diagnostic role of bone marrow blast percentage in the classification of myeloid neoplasms based on different classification criteria，and to provide a reference for optimizing diagnosis and treatment strategies. Methods A total of 236 patients diagnosed with myeloid neoplasms from 2016 to 2022 at Shanghai General Hospital of Shanghai Jiao Tong University School of Medicine were enrolled，consisting of 56 patients with myelodysplastic syndrome （MDS） and 180 patients with acute myeloid leukemia （AML）. According to the 2022 updated international consensus and classification criteria，the patients were classified into Group A（blast percentage<10%），Group B（10%≤blast percentage<30%）and Group C（blast percentage≥30%）. Group B was further subclassified into Subgroup 1（10%≤blast percentage<20%）and Subgroup 2（20%≤blast percentage<30%）. The clinical and laboratory characteristics between the groups were compared. Cox regression model was used to evaluate the prognostic factors for myeloid neoplasms. Results There was no statistical significance in clinical and laboratory results between Group A and Group B（P>0.05）. However，statistical significance was observed between Group B and Group C. Group C had a younger median age（P=0.007），higher hemoglobin levels（P<0.001），and higher white blood cell counts（P<0.001）. The mutation rates of CEBPA，KIT，NRAS，NPM1 and FLT3-ITD in Group C were higher（P=0.009，P=0.007，P=0.042，P=0.016，P=0.001）. Apart from peripheral white blood cell count（Subgroup 2 higher，P=0.005）and chromosomal karyotype abnormalities（Subgroup 1 having more extra-chromosomal abnormalities，P=0.008），there was no statistical significance in the other laboratory results between Subgroup 1 and Subgroup 2. SF3B1 mutations were associated with a lower blast percentage（P=0.006），while TP53 mutations were correlated with elder age and complex karyotype，which are considered poor prognostic factors（P=0.003，P<0.001）. High blast percentage，low treatment intensity and TP53 gene mutations were identified as adverse prognostic factors for survival in myeloid neoplasm patients. Allogeneic hematopoietic stem cell transplantation（HSCT） improved prognosis（P=0.005，P<0.001，P<0.001，P<0.001）. In Group B，the mortality risk was higher in males than that in females（P=0.009），and the mortality risk was higher in patients with BCOR gene mutations in Group 3（P=0.011）. Conclusions Myeloid neoplasm patients with 10%≤blast percentage≤30% have a better prognosis than those with AML with blast percentage ≥30%. The blast percentage is a prognostic indicator for clinical treatment. The statistical utility of blast percentage as a continuous variable（P=0.005） is much greater than when treated as a categorical variable（P=0.047）. High blast percentage，low treatment intensity and TP53 mutations are associated with poor prognosis，while allogeneic HSCT improves clinical outcomes. Statistical significance in clinical characteristics has been observed in patients with SF3B1 and TP53 mutations.

Key words: Myeloid neoplasm, Laboratory diagnosis, Blast percentage, Revised criterium, Genetics, Prognosis