Introduction

Development of effective treatments for cancer has significantly improved survival rates for hematological cancer patients. For example, in 1964 the 5-year survival rate for acute lymphoblastic leukemia (ALL) was 3%; in 1995–2001, it was 86% (Leukemia and Lymphoma Society, 2005; Ries et al., 2005). However, survival is often associated with negative effects on cognitive functioning which interfere with patients' current and future functional status.

In patients with hematological malignancies, risk factors for cognitive disorders are present during all stages of the disease and treatment process. Risk factors include cancer treatments, anemia and fatigue, immune response activity, central nervous system (CNS) involvement of the primary malignancy (especially in the case of ALL), disease and treatment complications affecting the CNS such as infection, hemorrhage, degeneration and leukoencephalopathy, and cognitive and psychiatric disorders that occur in the general population independent of having cancer.

Information on the long-term neuropsychological effects of cancer therapies is an important component of not only the informed consent process, but also the treatment planning process. In the risk-benefit analysis for selecting treatment, survival rates alone may be insufficient because some treatments are associated with significant depletion of cognitive and functional abilities.

Neurological Complications Independent of Cognitive Deficits

Neurological complications, independent of cognitive complaints, are common in hematological cancer patients. Neurological complications have been reported in 11%–65% of hematopoietic stem cell transplantation (HSCT) patients (Faraci et al., 2002; Gallardo et al., 1996; Graus et al., 1996; Harder et al., 2002; Sostak et al., 2003) and may be the main cause of death in 8.5%–26% of recipients (Faraci et al., 2002; Gallardo et al., 1996; Snider et al., 1994; Sostak et al., 2003).