Incidence, Clinical Characteristics, and Prognostic Significance Of Chromosome 3q Abnormalities In Patients With CML Blast Phase

We retrospectively reviewed cases of CML BP seen at our institution between 2000 and 2012 and analyzed their clinico-pathologic characteristics, response to therapy, and outcome. We then compared patients with BP and chromosome 3q abnormality (3q-POS) to patients with BP but without involvement of chromosome 3q (3q-NEG). A total of 320 patients with CML BP were analyzed. Among those, 38 pts (12%) had abnormalities of chromosome 3q. Abnormalities involving 3q were represented as follows: t(3;21) in 33%; inv(3), 24%; del 3q, 12%; t(3;4), 6%; t(3;7), 6%; t(3;8), 6%; t(3;6;7), 3%; t(3;11), 3%; t(2;3), 3%; and 3q+ in 3%. The characteristics of the two cohorts: 3q-POS vs. 3q-NEG are outlined in Table 1. The clinical characteristics were similar between the 2 cohorts. However, there were trends for older age and higher peripheral blast percentage in patients with 3q-POS. A similar percentage of pts received chemotherapy, stem cell transplant (SCT), and tyrosine kinase inhibitor (TKI, alone or combined with chemotherapy) among the 2 groups as their initial therapy for BP. Likewise, there was no significant difference in the percentage of pts eventually going for SCT. Patients with BP and 3q-POS had a significantly lower rate of complete hematologic response (CR, 22% vs. 45%), complete cytogenetic response (CCyR, 0% vs. 24%), and a higher rate of resistance (74% vs. 45%) to their first BP therapy compared to those with 3q-NEG. This translated into a trend towards lower median overall survival (OS) (7.5 vs. 9.9m, p=0.157) in pts with 3q-POS. Figure 1.