Cognitive speed of processing and functional declines in older cancer survivors: an analysis of data from the ACTIVE trial

Abstract

It has been suggested that chemotherapy treatment for cancer may contribute to cognitive decline in older cancer survivors. This issue is particularly important given that subtle cognitive impairment, particularly in cognitive processing speed, can affect functional status and quality of life for older adults. Multivariate regression of data from a longitudinal randomized controlled trial of older adults revealed a trend towards decreased performance after cancer treatment with chemotherapy on several functional measures associated with processing speed (as compared with matched individuals who did not have cancer). Additional analyses revealed that a subset of the chemotherapy-treated adults demonstrated a reliable negative change on several measures of processing speed. While inconclusive, this hypothesis generating work suggests that cognitive dysfunction following cancer treatment may contribute to disability observed in older cancer survivors. Further research is needed to determine the significance of the relationship between cognitive and functional impairment in older cancer survivors.

FIGURE 1

Disablement Process Model demonstrating relationship between cognitive impairment and disability in cancer survivors

FIGURE 2

Timing of assessments in the ACTIVE Study 2802 Persons aged 65-94 were enrolled in ACTIVE between March 1998 and October 1999 at 6 different study sites. The study was initially funded through Annual Visit 3 (AV3), and was extended through AV5. No data was collected for AV4, however. In addition, questions concerning cancer treatment were not asked at Annual Visit 1. For this analysis, data from the assessment 2-years prior to the individual's report of cancer were utilized as the baseline for the individual participant and their matched untreated participant, and data from the visit at which they reported treatment with chemotherapy was utilized as the post-chemotherapy time-point. Thus individuals reporting chemotherapy treatment may have been approaching 2 years post-chemotherapy.

Figure 3

Change on Speed of Processing Batteries from Pre-Chemotherapy to Post-Chemotherapy Assessment Note: This figure demonstrates the percent of participants demonstrating a reliable change and the direction of change for each speed of processing test by treatment group. RCI = (posttest − pretest) / SE_meas; SE_meas = SD * √(1 − r₁₁) SD = standard deviation of the measure r₁₁ = the reliability of the measure (Cronbach's alpha from sample for UFOV and RST; test-retest reliability for TIADL composite; reliability found in WAIS-R manual for digit symbol).