Prognosis of CML

Median survival is 4-6 years (can range from less than 1 year to more than 10 years)

• however occasionally patients die within a few months
• 3% of patients live more than 15 years without radical therapy
• once the accelerated phase is reached survival is usually less than 1 year and in the blast phase, few patients survive more than a few months (1).

It is important to identify the prognostic factors at diagnosis. The following can be used to provide useful prognostic information in a patient with CML:

• accurate identification of the disease stage (or phase) is considered to be the essential factor
• clinical and laboratory features - used to calculate prognostic scores (Sokal score or Hasford score)
  • these scores identifies patients with low, intermediate, and high risk of short term survival
• cytogenetic changes e.g. - deletions of the derivative chromosome 9
  • Imatinib can be used to partly overcome the negative prognostic effects of this
  • but the size and location of the deletion appears to be important
• degree and timing of haematological, cytogenetic, and molecular responses (2)

Approximately 60% of young adults with successful allogeneic bone marrow transplantation are cured.

Studies have revealed that the following features are predictive of a shorter chronic phase:

• increased splenomegaly.
• older age
  • chronic myeloid leukaemia mortality is strongly related to age, with the highest mortality rates being in older people. In the UK in 2014-2016, on average each year two-thirds (66%) of deaths were in people aged 75 and over

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• male gender
• elevated serum lactate dehydrogenase.
• cytogenetic abnormalities in addition to the Ph1.
• a higher proportion of marrow or peripheral blood blasts.
• basophilia.
• eosinophilia.
• thrombocytosis.
• anaemia (1)

Reference:

• (1) National Cancer Institute at the National Institutes of Health. Chronic Myelogenous Leukemia Treatment
• (2) Hehlmann R et al. Chronic myeloid leukaemia. Lancet. 2007;370(9584):342-50.
• (3) CRUK. Chronic myeloid leukaemia (CML) mortality statistics (Accessed 28/5/2019)