Vitamin B12 Deficiency After Gastrectomy for Gastric Cancer: An Analysis of Clinical Patterns and Risk Factors

Abstract

OBJECTIVE: To identify risk factors for postgastrectomy vitamin B12 deficiency and the time course of its development. BACKGROUND: Postgastrectomy vitamin B12 deficiency worsens the quality of life of gastric cancer survivors, and vitamin B12-related neuropathy is irreversible if recognized late. However, the clinical pattern of vitamin B12 deficiency development after gastrectomy remains unclear. METHODS: We reviewed 645 patients with gastric cancer who underwent distal subtotal gastrectomy (DG; n = 469) or total gastrectomy (TG, n = 176) between 2003 and 2010. Univariate and multivariate analyses were performed to identify risk factors for vitamin B12 deficiency and time to deficiency. RESULTS: Cumulative vitamin B12 deficiency rates were 100% for TG and 15.7% for DG 4 years after surgery (P < 0.001). The median time to vitamin B12 deficiency was 15 months after TG, whereas the median time was not reached after DG. Preoperative vitamin B12 level was the only risk factor for vitamin B12 deficiency after TG, whereas both preoperative vitamin B12 level and age were risk factors after DG. There was positive linear correlation between preoperative vitamin B12 levels and the time to vitamin B12 deficiency after either TG (P < 0.001) or DG (P = 0.017). CONCLUSIONS: Vitamin B12 deficiency is an inevitable and rather early metabolic sequela after TG. Elderly patients with low preoperative vitamin B12 levels are more likely to experience vitamin B12 deficiency after DG. Thus, preoperative measurement and regular postoperative monitoring of vitamin B12 levels are necessary for early detection and treatment of postgastrectomy vitamin B12 deficiency.