Background:

Some patients have cognitive impairment and fatigue after chemotherapy. We evaluated these symptoms and potential mechanisms in CRC patients and healthy controls (HC).

Methods: 

Cognitive function was evaluated in CRC patients and HC at baseline (pre-chemotherapy), 6 and 12 months. Group 1A received chemotherapy and Gr 1B none. Gr 2 had limited metastatic CRC. All completed cognitive assessment and self-reported fatigue, QOL, anxiety/depression, and perceived cognitive function. Blood tests evaluated: 10 cytokines, clotting factors, sex hormones, CEA, CBC and apolipoprotein genotyping as causal factors. Primary endpoints: cognitive function and fatigue at 12 months. Associations between results and demographic and disease-related factors were sought. 

Results: 

365 CRC patients (176 Gr 1A, 117 Gr 1B, 72 Gr. 2) and 72 HC were assessed. Median age 59 (23-75); 62% male. Cognitive impairment: baseline Gr 1A 33.5% vs 1B 32%, Gr 1 33% vs HC 10% (OR 4.5 [95%CI 2-10.2]); 12 months Gr 1A 19% vs 1B 16%, Gr 1 19% vs HC 4% (OR 4.9 [1.5-16.5]). Cognitive decline from 0-12 months: Gr 1A 31%, Gr 1B 22%, and HC 13% (p=.03). Perceived cognitive impairment at 12 months: Gr 1A 19% vs  1B 7%  (p=.04), Gr 1 14% vs HC 0% (p=.009).   Fatigue was greatest in Gr 1A (70%) at 6 months; at 12 months Gr. 1A 45% vs 1B 31% (p=0.056), Gr 2 61%, HC 36%. Cytokines were elevated in CRC patients compared to HC. No association was found with cognitive function and: fatigue, QOL, anxiety/depression, cytokines, sex hormones, clotting factors, CEA or apoE genotype. Objective cognitive function was weakly associated with perceived cognitive function.

Conclusions:

CRC patients had more cognitive impairment at baseline, 6 and 12 months than HC. Impairment was not significantly different between those who did and did not receive chemotherapy. Mechanisms of cognitive impairment remain unknown. Fatigue improved with time.