B-vitamins and treatment for large bowel cancer: a toxic relationship?

Up to 80% of patients with large bowel cancer receiving chemotherapy or radiotherapy experience side-effects due to their treatment. These side-effects do not only have impact on quality of life but may also result in alterations of the treatment for large bowel cancer. B-vitamins, like folate, vitamin B6, and vitamin B12, may interact with the cancer treatment due to the treatment’s mechanism of action. However, the intake and status of B-vitamins is often overlooked during cancer treatment. In this thesis, I aimed to unravel the role of B-vitamins in treatment tolerance in patients with large bowel cancer. Deficient and excess concentrations of folate, vitamin B6 and B12 increase the risk of side-effects of chemotherapy. Excess concentrations are likely the consequence of dietary supplement use, which is common in patients with large bowel cancer. Optimizing blood levels of B-vitamins before and during cancer treatment may be an important future strategy within oncology care.