[Myelopoiesis and Bone Marrow Function in Elderly Tumor Patients]

According to a model described by Balducci, the human myelopoietic stem cell reserve shows a shift from the reproductive to the proliferative pool corresponding to higher immunological demands resulting from the breakdown of infection defences. Every "hematopoietic stress," i.e., sepsis and/or cytoreductive chemotherapy, leads to a reduction of myelopoietic stem cells in the elderly in contrast to an increase in younger individuals. These changes are relevant starting at the age of 70 years and show a reduced compensation capacity in the aged organism. In addition, the function of the effector cells, i.e., the granulocytes and especially their phagocytic capacity, as well as the balance between stimulating and inhibiting cytokines are compromised. A significant influence on leukopenia and febrile septicemia has been shown for several comorbidities, especially chronic inflammation. The prophylactic use of myelopoietic growth factors is, therefore, recommended for the elderly when there is an expected risk for hematotoxicity grade III or IV. However, prognostic tests to predict the individual risk of hematotoxicity and septicemia are lacking.