This is a prospective, longitudinal, controlled study of cognitive function and fatigue in patients with apparently localized CRC treated with adjuvant or neoadjuvant chemotherapy. In addition to following each patient over time (i.e. acting as their own control), a separate control group will consist of patients with early stage CRC (Stage A or B) who have had surgical resection of their tumour, but who do not require adjuvant chemotherapy, or patients with stage C CRC who have declined chemotherapy.