Therapeutic and prognostic value of initial chromosomal findings at the blastic phase of Ph1-positive chronic myeloid leukemia.

To assess parameters of therapeutic response and of survival after the onset of the blastic phase (BP) in 64 patients with Ph1-positive chronic myeloid leukemia (CML), a number of clinical, hematologic, and cytogenetic data at the BP were evaluated. Among 10 parameters checked, only the chromosomal findings correlated with the therapeutic response and survival after the onset of the BP. The patients were divided into three groups on the basis of the chromosome findings in the bone marrow, blood, and spleen: (1) those with only a Ph1 (PP), (2) those having two types of clones, i.e., one clone with only a Ph1 and another with additional karyotypic changes (AP), and (3) those with only abnormal clones in addition to the Ph1 (AA). The number of patients in each group was 29 in PP, 15 in AP, and 20 in AA. The results were as follows. (1) The percentage of patients with a good therapeutic response was 79% (23/29) in PP, 53% (8/15) in AP, and 30% (6/20) in AA. (2) The median survival after the onset of the BP was 171 days (5.7 mo) in PP, 146 days (4.9 mo) in AP, and 74 days (2.5 mo) in AA. Statistically, there was a significant difference between the AA and the other two groups (p less than 0.05). For further study, the AA and AP patients were divided into 4 subgroups each: those with 48 or more chromosomes, those with 47 chromosomes, those with pseudodiploidy, and those with hypodiploidy. A subgroup with 48 or more chromosomes in the AA patients had a very short survival (median, 25 days; 0.8 mo) and a poor therapeutic response (1/9, 11%). Our observations suggest that the lack of a clone with only a Ph1 (AA), particularly with more than 48 chromosomes, at the acute crisis or shortly after the onset of the BP indicates an unfavorable therapeutic response and a poor prognosis after the onset of the BP.