[Clinical study of Philadelphia chromosome-positive adult acute lymphoblastic leukemia]

To study the clinical characteristics, risk factors and therapeutic outcome of Philadelphia chromosome-positive adult acute lymphoblastic leukemia (Ph(+)aALL).

The clinical data of 117 newly diagnosed adults with Ph(+)ALL in our hospital between January 1995 and December 2009 were retrospectively analyzed. And their prognoses were followed up.

There were 117(16.1%) of 727 aALL patients diagnosed as Ph(+)aALL. Among the 117 cases, 64.1% patients were classified as pre-B immunophenotype and 31.3% as common B immunophenotype, 37.5% patients with co-expression of myeloid antigens (CD13 or CD33), and 98.4% patients with positive CD34. The complete remission (CR) rate after 1 or 2 cycles of induction chemotherapy was 62.2% in Ph(+)aALL group versus 82% in Ph(-)aALL group (P = 0.000). The median disease-free survival time of Ph(+) group was 6 months and the median survival time was 9 months. Sole karyotype abnormality subgroup t(9;22) accounted for 53% of all Ph(+)aALL patients and additional karyotype abnormality subgroup, t(9;22) plus other chromosome variation, accounted for 47%. Patients in sole karyotype abnormality subgroup had slightly lower CR rate (59.6% vs 62.5%, P = 0.768), longer median survival time (7 months vs 4 months, P = 0.158), and higher 3-year overall survival rate (27.3% vs 14.4%, P = 0.271). For the myeloid antigen co-expressed patients and the only lymphocytic antigen expressed ones, CR rate was 56.0% and 61.5% (P = 0.750), the median survival time was 5 months and 4 months (P = 0.182), and the 3-year overall survival rate was 16.0% and 15.0% (P = 0.354), respectively. In the imatinib plus combination chemotherapy treatment group, 81.3% patients achieved CR, compared with that of 58.3% in patients treated with only traditional combination chemotherapy (P = 0.083). The median survival time was 9.5 months and 6 months (P = 0.003) in these two subgroup, and 3-year overall survival rate was 52.2% and 10.3% (P = 0.029), respectively. For the patients receiving allo-HSCT after CR and that receiving traditional consolidation chemotherapy, the median survival time was 15 months and 6 months (P = 0.000), and the 3-year overall survival rate was 62.0% and 10.3% (P = 0.000), respectively. For the patients receiving imatinib as consolidation-maintenance treatment and that receiving allo-HSCT, the median survival time was 12 months and 15 months (P = 0.300), and the 3-year overall survival rate was 64.7% and 62% (P = 0.505), respectively.

Of all adult ALL patients, the Ph(+) subgroup accounted for about 16.1%, which have unfavorable prognosis such as lower CR rate and shorter survival duration under traditional chemotherapy. Neither additional chromosome abnormalities to t(9;22) nor co-expression of myeloid antigen had negative effect on CR rate and survival duration. Addition of imatinib to the therapy was beneficial to improve the CR rate and survival duration. Either receiving imatinib as consolidation-maintenance treatment or allo-HSCT after complete remission can improve long-term survival rate of Ph(+) adult ALL group significantly.