[Analysis of clinical characteristics and prognostic influencing factors in patients with chronic myeloid leukemia myeloid blast-phase].

Objective

To analyze the clinical characteristics and factors influencing survival time in patients with chronic myeloid leukemia myeloid blast-phase (CML-MBP).

Methods

The patients with CML-MBP treated at Henan Cancer Hospital from September 2009 to July 2024 were retrospectively enrolled. The patients were stratified into two groups based on different treatment regimens: the combination group [the patients receiving tyrosine kinase inhibitors (TKI) combined with an acute myeloid leukemia-type regimen following CML-MBP diagnosis] and the monotherapy group (the patients receiving TKI monotherapy). With follow-up extending from CML-MBP diagnosis until October 16, 2024, clinical characteristics were compared between groups. Potential factors influencing survival time were analyzed using Cox regression models.

Results

A total of 141 patients were enrolled: 107 in the combination group [64 males and 43 females, aged M (Q1, Q3), 43 (32, 52) years] and 34 in the monotherapy group [19 males and 15 females, aged 51 (45, 61) years]. The median follow-up duration was 6.5 (2.5, 15.1) months. About 90.1% (127/141) of the patients had a history of chronic/accelerated phase. During CML-MBP, 78.7% (111/141) of the patients had received TKI therapy. Extramedullary blast phase occurred in 18.4% (26/141) of the patients, with 5.0% (7/141) presenting as isolated extramedullary myeloid blast phase. Additional chromosomal abnormalities were detected in 57.4% (81/141) of the patients, of whom 63.0% (51/81) exhibited complex chromosomal karyotypes. Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase domain mutations were identified in 58.0% (65/112) of the patients, with the T315I mutation being the most common. The patients in the combination group were younger at diagnosis than those in the monotherapy group. The proportions of complex chromosomal abnormalities [63.6% (68/107) vs 38.2% (13/34)] and treatment with third-generation TKI following blast phase [43.0% (46/107) vs 14.7% (5/34)] were higher than those in the monotherapy group. The proportions of the patients with white blood cell count [14.1 (4.3, 48.9)×10⁹/L vs 50.1 (11.5, 149.0)×10⁹/L], serum lactate dehydrogenase level [510 (297, 930) vs 900 (535, 1 898) U/L], and treatment with imatinib following blast phase [8.4% (9/107) vs 20.5% (7/34)] were all lower than those in the monotherapy group (all P<0.05). Among 104 and 28 evaluable patients who completed efficacy evaluation in the combination group and monotherapy group, respectively, the major molecular response (MMR) rate was higher in the combination group [16.3% (17/104) vs 3.6% (1/28), P=0.049]. The 1-year survival rate did not differ significantly between the groups (37.8% vs 32.4%, P=0.101). Multivariate Cox regression analysis showed that isolated extramedullary myeloid blast phase (HR=0.211, 95%CI: 0.064-0.704), achievement of major hematologic response (MHR) (HR=0.184, 95%CI: 0.102-0.330), and/or deep molecular response (DMR) (HR=0.119, 95%CI: 0.028-0.504) were identified as independent protective factors for survival. Conclusions Most patients with CML-MBP have a history of chronic or accelerated phase disease and TKI therapy, frequently accompanied with complex chromosomal karyotypes and the T315I mutation. While patients receiving TKI combination therapy demonstrate higher rates of MMR, their overall survival remains poorer. Isolated extramedullary acute myeloid blast phase, and the achievement of MHR and/or DMR through treatment are beneficial for the survival of patients with CML-MBP.