Effect of Vitamin B12 Replacement Intervals on Clinical Symptoms and Laboratory Findings in Gastric Cancer Patients after Total Gastrectomy

The management of patients with vitamin B12 deficiency after total gastrectomy (TG) remains controversial. We aimed to evaluate the effect of vitamin B12 replacement intervals on the clinical characteristics in these patients. The data from patients who received vitamin B12 supplementation after TG between 2007 and 2018 at the National Cancer Center, Korea, were retrospectively evaluated. Vitamin B12 deficiency was defined as a serum vitamin B12 level of <200 pg/mL or urine methylmalonic acid level > 3.8 mg/gCr. The patients were divided into a regular replacement group (patients received an intramuscular injection or oral medication regularly), and a lab-based replacement group (patients received vitamin B12 intermittently after checking the level). The symptoms and biochemical parameters were compared between these groups. The regular and lab-based replacement groups included 190 and 216 patients, respectively. The median vitamin B12 replacement intervals were 1 and 9 months, respectively (p < 0.001). After replacement, the regular replacement group had higher vitamin B12 levels than the lab-based replacement group (p < 0.001). However, the serum hemoglobin level showed no significant changes. After replacement, there was no significant difference in the proportion of the symptomatic patients between the groups. Replacing vitamin B12 with a lab-based protocol may be sufficient for TG patients.