Does my older cancer patient have cognitive impairment?

Cancer and impaired cognition are both frequent conditions in old age and consequently coexist to certain degree. The prevalence of impaired cognition increases sharply after the age of 65 and the more advanced form of cognitive impairment; dementia, is exceeding 30% by the age of 85years. Adequate cognition is crucial for understanding important facts and for giving consent for intervention. There are many different stages of cognitive impairment, ranging from subjective cognitive impairment to severe dementia. The mildest stages of cognitive impairment are sometimes reversible but in more severe stages, there is brain damage of some kind, most frequently caused by neurodegenerative disorder such as Alzheimer's disease. Therefore, some kind of evaluation of cognition should be offered to all older individuals with cancer and in need for intervention. In this evaluation, information should also be sought from a close relative. In the earlier stages of cognitive impairment, the individual usually retains ability to give consent and understands information given but in later stages of dementia, a surrogate decision maker is needed. In milder stages of dementia, an individual evaluation is needed for decision of capability for consent. A specific diagnosis of a disorder such as Alzheimer's disease does not in itself preclude the individual from giving consent, the degree of cognitive impairment, impaired judgement and poor insight are more decisive in this regard. It is also important to know the difference of delirium, most often a time limited condition and dementia that usually is progressive.