Purpose: Since interferon alfa (IFN-A) became an established treatment in c
hronic myelogenous leukemia (CML), more patients are referred to tertiary c
enters in late chronic phase (ie, > 12 months after diagnosis). Trials cond
ucted in this phase cannot be evaluated precisely unless the features that
determine prognosis in late chronic-phase CML are identified. The purpose o
f this study is to define the prognostic determinants of late chronic-phase
CML.
Patients and Methods: From 1980 to 1997, 257 consecutive CML patients refer
red in late chronic phase were studied. Their clinical characteristics at t
he time of referral and their association with survival were investigated.
A staging model was designed.
Results: The median survival from time of referral was 43 months. Pretreatm
ent characteristics associated with worse outcome included older age, poor
performance status, splenomegaly, low albumin level, high percentage of bla
sts or basophils in peripheral blood (PB) or bone marrow, longer duration o
f chronic phase, and poor-risk group as defined by the Synthesis model. out
come. By multivariate analysis, characteristics associated with shorter sur
vival were age of 60 years or older, time from diagnosis of 3 years or grea
ter, performance status of 1 or greater, PB basophils of 7% or greater, spl
een 10 cm or greater, PB blasts 3% or greater, and albumin level less than
4 g/dL, A model that included age, duration of: chronic phase, performance
status, and PB basophils was generated. Patients with no, one, two, or thre
e or greater adverse factors had median survivals of 71, 49, 26, and 19 mon
ths, respectively.
Conclusion: A staging model for late chronic-phase CML can stratify patient
s in four groups with significantly different outcomes. If confirmed in ind
ependent populations, such a model could be considered in the analysis of f
uture trials of treatment strategies in late chronic-phase CML. (C) 1998 by
American Society of Clinical Oncology.