Vitamin B12 status after right hemicolectomy in bowel cancer patients: A feasibility study

INTRODUCTION: Terminal ileum resection in patients with Crohn’s disease results in vitamin B12 deficiency and these patients are routinely given B12 supplementation to prevent anemia and neuropsychiatric disease. The effect of right hemicolectomy on B12 status in cancer patients has not previously been studied. Total serum B12 is an unreliable test. Second-line diagnostic tests measure methylmalonic acid (MMA) and homocysteine (tHcy) are also used. An assay measuring an active form of B12 is available for routine use. This observational study investigated whether B12 deficiency exists in patients after a right hemicolectomy for cancer. METHODS: Patients (n=28; age range=52-88 years) who had undergone a right hemicolectomy for cancer and been in remission for two years were identified from a database and recruited to an outpatient clinic along with an age-matched control group (n=27; age range=52-89 years). Vitamin B12 status in both patients and controls was assessed by the measurement of vitamin B12 (total and active)͕ MMA and tHcy. RESULTS: Concentration of tHcy was significantly higher (p<0.05) in the surgical group (14.0 µmol/L) compared with the controls (11.1 µmol/L). There were no significant differences in total and active B12, folate and MMA concentrations between the two groups (p>0.05). DISCUSSION: Right hemicolectomy for malignancy is associated with an increase in tHcy concentrations although a larger study is required to determine the B12 status in post-operative right hemicolectomy patients.