This is a prospective, longitudinal cohort study to evaluate fatigue and cognitive function in patients with colorectal cancer (CRC) treated with chemotherapy, and in patients with the same malignancy, that do not receive chemotherapy. A self-report questionnaire for fatigue (the FACT-F), and validated tests of cognitive function, will be applied at predetermined times before, during and after chemotherapy, to determine the incidence, severity and duration of these symptoms. Comparisons will be made in changes in cognition for individuals, as well as between the chemotherapy and the control group. Mechanisms that might lead to fatigue and/or cognitive decline will be investigated.

We will undertake a prospective, longitudinal controlled study of fatigue and cognitive function in 120 patients with localized CRC who receive 5FU-based adjuvant chemotherapy. Each patient will be evaluated at baseline and at 6, 12 and 24 months for fatigue (using the FACT-F questionnaire) and for cognitive function, using validated tests: these will comprise both traditional neuropsychological tests and the computerised CANTAB™, a which is less dependent on fluency in English. Results during and after chemotherapy will be compared with the pre-chemotherapy assessment (so that each patient acts as their own control). Since baseline evaluation may be confounded by the recent diagnosis and surgery we will include an independent control group of 120 patients who have undergone surgery for CRC but who do not receive chemotherapy. Patients found to have cognitive change will be offered further comprehensive neuropsychological assessment. We will also evaluate quality of life (QOL) using the FACT-G questionnaire and anxiety and depression using the General Health Questionnaire (GHQ). Blood tests including hormone levels, cytokines, homocysteine, procoagulants and apo-lipoprotein E-є4 allele status will evaluate possible mechanisms. Finally, since chemotherapy for CRC is evolving to include the more toxic drugs oxaliplatin and irinotecan, we will perform a parallel pilot study evaluating pts with early recurrent or metastatic CRC who receive these drugs, using similar methods of evaluation.

Inclusion Criteria:

• Histologically confirmed colorectal cancer
• Age 18-75
• Eastern Cooperative Oncology Group (ECOG) performance status 0-1
• Life expectancy of at least 12 months
• Full recovery from any post operative sequelae
• Adequate hepatic function as documented by a serum bilirubin < 18 umol/L, and liver function tests (LFTs) within 1.5X normal range
• Informed consent

Exclusion Criteria:

• Any major pre-existing psychiatric history or dementia, alcohol abuse, or currently using a psychotropic medication that might lead to cognitive problems, other than short acting benzodiazepines for nausea or sleep
• Any evidence of metastatic disease other than group C who may have limited metastatic disease. If there is clinical suspicion of central nervous system (CNS) involvement patients must have brain imaging (MRI or CT scan) prior to recruitment.
• Ongoing sepsis or uncontrolled infection, including HIV infection
• Pre-existing neurological condition likely to interfere with ability to perform cognitive testing
• Any other severe co-morbidity which, in the judgement of the investigator, would make the patient inappropriate for entry into this study
• Active cancer within the last 5 years other than squamous or basal cell carcinoma of the skin or cervical cancer in situ (except for CRC)
• Previous history of chemotherapy, other than adjuvant chemotherapy for group C metastatic group > 1 year previously
• Minimal English skills such that subjects would be unable to follow simple, written English instructions and to read questionnaires of a grade 8 standard with the help of a research assistant.

colorectal cancer patients aged 18-75