Aims: Chemotherapy-related cognitive impairment (CRCI) is commonly reported following the administration of chemotherapy in cancer patients. The aims were to assess whether CRCI is consistently observed in people treated for colorectal cancer and to identify the domains of cognition affected.
Method: This study comprises four sample groups, all who, except for the healthy controls, have been diagnosed with colorectal cancer; participants who have been treated with chemotherapy (n = 19), participants who received treatment with the anti-vascular drug Avastin (n = 12), participants who have received only surgery (n = 10), and a healthy control group (n = 20). Each participant undertook approximately 90 minutes of neuropsychological testing which assessed four cognitive domains, defined by Lezak, Howieson and Loring (2004): verbal functions and language skills, orientation and attention, construction, memory.
Results: A multivariate analysis of variance revealed a statistically significant difference between the groups in all four cognitive domains (F(12,143)=1.58). Post-hoc tests revealed poorer performance for the surgery group compared to the healthy controls in verbal functions and language skills, and memory, and lower memory scores for the surgery group compared to the chemotherapy group. A univariate analysis of variance showed no statistically significant difference between the groups for the Everyday Problems Test. However, correlation analyses revealed statistically significant positive relationships between all four domains and EPT score (p<.01 for all correlations).
Conclusions: Results support previous reports that cognitive impairment may occur in patients treated for cancer. However, suggestions that chemotherapy impacts cognition more than other forms of treatment are not supported by our results, with the surgery patients being the only group to be significantly different in their cognitive performance from the healthy controls. The relationship between everyday problem solving and cognitive performance in cancer patients must be investigated in future research.