Vitamin B12 malabsorption after irradiation for gynaecological tumours.

The serum vitamin B12 levels were determined in 44 asymptomatic patients at least one year after completion of pelvic irradiation for a gynaecological tumour. Ten patients (23%) were found to have decreased levels of serum vitamin B12, of which six (14%) were assumed to be caused by malabsorption due to radiation damage to the terminal ileum as no other reason for a lower vitamin B12 level could be detected. Neither the radiation dose or volume nor the manifestation of acute or late radiation side effects appeared to be correlated with the finding of decreased levels of vitamin B12. It is concluded that even in asymptomatic patients who received pelvic irradiation, serum vitamin B12 levels can serve as a marker for radiation enteropathy. It is advocated to check vitamin B12 levels prior to the radiation treatment as well as during the follow-up of these patients.