Multicenter Study of Epidemiology and Outcome of Chronic Myeloid Leukaemia (CML) in Egypt

Abstract

Chronic myeloid leukaemia (CML) is a myeloproliferative disorder characterized by the presence of Philadelphia chromosome. The other important risk factors are high doses of ionizing radiation, alcohol, obesity and occupational exposure to benzene. The disease has three phases, chronic phase (CP), accelerated phase (AP) and blastic crisis (BC). CML has a worldwide incidence of 1-1.5 cases per 100,000 inhabitants. CML constitutes 15-20% of all leukemias. The median age at diagnosis is 40-60 years. CML incidence rates in western countries vary from 0.6 to 2 cases per 100,000 inhabitants Highest rates were reported from Switzerland, USA, Italy, Australia, Germany, and UK. Lower rates were reported for Netherlands, Sweden, China, and India. Little is known about burden and epidemiological information concerning CML in Egypt. There is recent interest to observe incidence and mortality because of advent of new diagnostic and treatment policies for CML. Reliable epidemiological information on chronic myeloproliferative disorders is rare. Geographic and/or ethnic variations contribute to the variability of incidences among registries. The incidence of Philadelphia-positive (Ph+) chronic myeloid leukaemia increases with age: the reported median age at diagnosis is more than 60 years in epidemiologic registries and of approximately 50 to 55 years in clinical trials. Following the most widely accepted recommendations that set at 65 years the boundary between young and old persons, a relevant proportion of CML patients at diagnosis are “elderly.”

Older age has been considered a poor prognostic factor in patients with CML. The negative impact of age on response rates and long-term survival was observed regardless of the treatment strategy: Busulfan, Hydroxyurea (HU), Interferon-α (IFN-α), and allogeneic stem cell transplantation (SCT). The first ALN report demonstrated that age-specific rates for CML in Egypt and Arab nations are lower by at least two decades compared to western populations (highest in age group 30-35 years). Geographic and ethnic variations contribute to the variability of incidences among CML registries. Reliable data concerning response rates to therapy in Arab nations is lacking. CML management areas are not in line with the current recommendations, due to sub-optimal timing of treatment decisions, under monitoring, and lack of molecular techniques or TKIs. Median age differs between cancer registries and clinical trials by 10-20 years.