Clinical and prognostic features of Philadelphia chromosome-negative chronic myelogenous leukemia.

Between 1965 and 1982, 105 patients with a diagnosis of Philadelphia chromosome-negative chronic myelogenous leukemia were referred to our institution with minimal or no prior therapy. The median age was 63 years and 64% were males. The overall median survival from time of referral was 14 months; 53% of patients survived 1 year and only 10% survived beyond 5 years. At the time of analysis, 92 patients (88%) were dead, 56% of deaths being preceded by a blastic crisis. Compared with Philadelphia chromosome-positive disease, patients with Philadelphia chromosome-negative chronic myelogenous leukemia were older and had a significantly higher incidence of anemia, thrombocytopenia, monocytosis, marrow blasts, decreased marrow megakaryocytes and a lower incidence of basophilia and thrombocytosis. Chromosomal abnormalities occurred in 33% of patients and consisted most frequently of trisomy 8, or an additional chromosome C, loss of the Y chromosome, or abnormalities in chromosomes #5 and #7. Of nine pretreatment characteristics significantly associated with poor survival, a multivariate analysis identified four to have independent additive prognostic significance: severe thrombocytopenia, hemoglobin levels less than 10 g/dl, increasing peripheral blasts and promyelocytes, and age 60 years or older. Monocytosis was not of prognostic significance. The derived prognostic model divided patients into three risk groups, low, intermediate, and high, with median survivals of 36, 16, and 3 months, respectively. The authors conclude that Philadelphia chromosome-negative chronic myelogenous leukemia is a distinct entity among the myeloproliferative syndromes with characteristic clinical and laboratory features and a poor prognosis. Prognostic factors and related risk categories were demonstrated within this disease entity.