Table 1 Inclusion and exclusion criteria

• Histopathologically verified adenocarcinoma of the colon or rectum and planned standard adjuvant treatment with capecitabine in combination with oxaliplatin

• Age ≥ 18

• ECOG performance status 0-2 (measurement of a patient’s function in terms of self-care, daily activity and physical ability) [46]

• Written and orally informed consent.

• Inability to speak, read, and understand Danish

• Previous treatment with neurotoxic chemotherapy

• Neurological (including neuropathy) or psychiatric disorders, diabetes, or other significant medical conditions

• Alcohol or drug abuse

• Sensory disturbances in the feet

• Spinal stenosis

• Vascular disease (Fontaine grade II or more)

• Known allergy to fish, fish oil or corn oil

• Fertile patients not willing to use effective methods of contraception during treatment or abstinence

• Daily intake of oil supplements and not willing to stop during the trial period

• Lack of consent to skin biopsy