The frequency and clinical course of cognitive impairment in patients with terminal cancer.

BACKGROUND: Cognitive disorders are among the most frequent psychiatric complications of advanced cancer. This study reviews the frequency and clinical course of cognitive failure in patients with advanced cancer admitted to a palliative care unit.
METHODS: In this retrospective study, all 348 patients admitted to the Edmonton General Palliative Care Unit over a period of 26 months were reviewed. The Mini-Mental State Examination (MMSE) was used as a screening tool to assess cognitive functioning and was performed on all patients at the time of admission and once to twice weekly thereafter. In all cases, when cognitive failure was diagnosed, a standardized management protocol was followed.
RESULTS: Three hundred and twenty-one patients (92.2%) were evaluable. A total of 1441 MMSEs were performed. Each patient underwent an average of 4.7 +/- 4.26 MMSEs and every patient underwent an MMSE every 4.9 (+/- 3.3) days (median, 3.6 days). The mean age (standard deviation [SD]) of the study group was 64.2 (+/- 12) and the mean +/- SD (median) length of stay was 27 +/- 22 (20.5) days. Two hundred and thirty-one patients (71%) died on the unit. One hundred and forty-two patients (44%) had abnormal MMSE scores (MMSE < 0.8) on admission, whereas 176 patients (55%) had abnormal MMSE scores at the time of death or discharge. Of the 231 patients who died on the unit, 157 (68%) had abnormal MMSE scores prior to death. There was no significant difference in the first MMSE between patients who died and those who were discharged (P = 0.16). Of the 240 patients who underwent 2 or more MMSEs, 99 (41%) had normal initial and final MMSEs, 54 (23%) had normal initial MMSE scores but abnormal final scores, and 62 (26%) had both initial and final abnormal scores. Of the 87 surviving patients with an MMSE score of < 0.8 on admission, 25 (29%) had initial abnormal and final normal scores, indicating an improvement. Twelve of these 25 patients (48%) with abnormal initial scores but normal final scores were discharged versus 52 of 99 patients (53%) with normal initial and final MMSE scores (P > 0.2). Of 124 patients with normal final MMSE scores, 64 (52%) were discharged versus 16 of 116 patients (14%) who had abnormal MMSE final scores (P < 0.0001).
CONCLUSIONS: These data suggest that cognitive screening should take place in patients with advanced cancer because cognitive failure is highly prevalent in this population, is reversible in a significant proportion of patients, and the presence of sustained cognitive impairment is a poor prognosticator for discharge. However, these results need to be confirmed in prospective studies.