The biology and treatment of acute myeloid leukaemia in elderly patients
Acute myeloid leukaemia (AML) is predominantly a disease of the elderly; the median age is 64 years and almost 60% of cases are over 60 years old. Unfortunately however, the treatment of AML in elderly patients is generally unsatisfactory with significantly poorer remission rates and overall survival than in younger patients. We have designed a novel treatment regimen consisting of Mitozantrone and Cytosine Arabinoside specifically for elderly patients and have evaluated the regimen in 104 patients over 60 years old in the North West region. The complete remission rate was 58%, the median duration of remission was 11 months and the median survival was 9 months. These results compare very favourably with previous reports in elderly patients. The regimen was associated with tolerable toxicity and a gratifying improvement in the performance status of responders. Extensive univariate and mutivariate analysis of data arising from the study has been performed, and models to predict outcome of therapy and overall survival have been performed. The latter model may be particularly useful in assisting the identification of elderly patients who would benefit from intensive chemotherapy. The biology of AML in elderly patients has been studied with particular emphasis on morphology, cytogenetic abnormalities and in-vitro culture patterns. Compared with younger patients, cases of AML in the elderly have a high incidence of clinical and morphological myelodysplasia, frequently have prognostically adverse chromosomal abnormalities and have reduced in-vitro cloning efficiency. Thus intrinsic differences in the biology of AML in the elderly have been demonstrated which may, in part, account for the adverse prognosis of AML in elderly patients. The impact of new technologies upon the treatment of AML in the elderly is discussed with particular emphasis on the haemopoietic growth factors and new techniques for studying leukaemia biology.