Accumulating evidence for the effect of chemotherapy on cognition.

A strength of meta-analysis is that it provides a technique for examining broad trends in data across studies. However, there is consensus among many investigators associated with the International Cognition and Cancer Task Force that a subgroup of patients may be particularly vulnerable to post-treatment cognitive change. 10 Age and education were not shown to moderate the effects of chemotherapy-induced cognitive change in the present meta-analysis. However, as the authors acknowledge, most studies included relatively young to middle-aged patients who tend to be highly educated. Therefore, there may not have been sufficient numbers of patients who are older or who have lower education levels to yield significant associations. This possibility is illustrated in a recent study that demonstrated that age and cognitive reserve (which is influenced by such factors as education, occupation, and cognitive stimulation) were associated with post-treatment cognitive decline. Those older patients with low levels of pretreatment cognitive reserve who were exposed to chemotherapy were most vulnerable to post-treatment cognitive decline as assessed on measures of processing speed. 4