Hematological malignancies in the elderly: The epidemiological perspective

In the more developed countries the total number of new cases with a hematological tumour was 415,433 for all ages, whilst 188,654 occurred in people aged 70 or more years, representing the 45 % of total cases, equally divided into two sexes. The most these malignancies is closely linked to age and incidence rates increased exponentially after 50 years of age. Aetiology of hematological tumours is largely unknown. However the basic causal mechanism could be a decline in adaptive immunity, strongly related with individual age. In addition to such immunodeficiency, some specific risk factors have been found: viral infections, overweight and obesity (particularly for non-Hodgkin’s lymphomas - NHL), ionising radiation and chemical compounds (particularly for leukemia). Moreover, it must to be taken into account that mortality and survival, more specifically in the elderly, are influenced negatively by socio-economic deprivation. Considering geographical distribution, substantial variations in incidence and mortality across the world were observed. Incidence of younger and older adults was for all hematological malignancies higher in more developed countries. As regards mortality, younger people showed rates higher in developing countries, while the elderly in Western and developed areas. The epidemic growth of NHL incidence was not finished in the first decade of 2000, even if in Italian and US old populations the rates started leveling off. Unlike incidence, mortality was descending in the elderly. Leukemia incidence trends were very often stable or weakly growing, without any tendency to decrease, but for leukemia mortality it was possible to highlight an encouraging general picture with rates often decreasing. The elderly had always survival rates lower than those of middle aged adults. The prognostic disadvantage was larger at 1 than 5 years from diagnosis. The gap was smaller for NHL and acute myeloid leukemia, whereas the difference in survival was much larger for chronic myeloid leukemia and Hodgkin’s lymphoma. Summarizing, elderly patients had a marked prognostic disadvantage with respect younger adults. However, if an elderly subject survives the first period immediately after detection and overcomes the first difficulties of access to healthcare, experiences a prognosis similar to that of a younger patient.