361 The Prevalence and Timing of Vitamin B12 Deficiency Following Oesophagectomy and Subtotal Gastrectomy (STG)

Abstract Aim Vitamin B12 deficiency is a recognised risk following oesophagogastric surgery due to multifactorial causes, including reduced gastric acid and intrinsic factor production, and dietary changes. Whilst lifelong intramuscular supplementation is standard post-total gastrectomy, guidance following oesophagectomy and STG is lacking, leading to varied practice. This study aimed to assess the prevalence and timing of B12 deficiency in these patients. Method A retrospective review was undertaken on patients who had an oesophagectomy/STG between January 2020-December 2022, attending the survivorship clinic. Deficiency was defined as holotranscobalamin <25pmol/L, or 25–70pmol/L with elevated methylmalonic acid. B12 levels were collated from pre-operatively to approximately 2 years post-operatively. Results Fifty-five patients (33 oesophagectomy; 22 STG) were included. B12 results were not available for all patients at each timepoint. Prevalence of pre-operative deficiency was 13.0% (7/54). Three patients treated pre-operatively were excluded from post-operative analysis due to ongoing supplementation. Overall prevalence of post-operative deficiency was 26.9% (14/52), with 13.7% (7/51) within 1–12 months and 15.9% (7/44) from 13–27 months. Deficiency was higher post-oesophagectomy (30%) than STG (22.7%). The oesophagectomy subgroup had a higher proportion of older adults (≥65 years: 63.6% vs. 50%) and older mean age (67.7 vs. 64 years). Conclusions B12 deficiency is common post-oesophagectomy/STG, supporting the need for routine monitoring. Findings are limited by sample size and lack of longer-term data. Results suggest residual B12 absorption in most patients after oesophagectomy/STG, negating the need for routine supplementation. Further research is needed to elucidate the longer-term prevalence and evaluate efficacy of oral supplementation.