Endocrine Abstracts

Background: Neuroendocrine tumours (NET) are heterogenous group of tumours commonly arising from Gastro-pancreatic (GI) and pulmonary origins. Combination of bowel resection, disease related diarrhoea and somatostatin analogue therapy (SSA) can contribute to vitamin B12 deficiency (B12D). International guidelines do not suggest routine screening. Total serum cobalamin (B12) level can be falsely normal in patients with B12D. Cells take up B12 in the form of Holotranscobalamin (HoloTC) and measuring HoloTC has greater diagnostic accuracy for B12D. NICE recommended its use in indeterminate cases (B12 level 135-300 ng/l).

Aim: We aim to investigate our practice of B12 deficiency in our NET service. Method: Data of all NET patients from May 2007-May 2022 were reviewed retrospectively.

Results: Total number of NET were113 (13 deceased, 55 females, mean age 70.33 year ±SD 10.7, 86 GI origin, 17 pulmonary and 10 other source. 61 (54%) had a serum B12 level measured since NET diagnosis and 12 (19%) had B12D (P<0.0001). Interestingly, only 7 were GI NET, 10 on SSA, 5 had bowel resection and on SSA. Additional 14 (23%) patients’ cobalamin level were borderline. No HoloTC were carried out in those cases. Risk factors for B12D were present among those where cobalamin were not measured (36 GI NET, 21 bowel resection, 25 on SSA, and 6 had bowel resection and on SSA).

Conclusion: B12D is common in NET patients when assessment was carried out. Symptoms of B12 can be nonspecific and not all will have typical macrocytic anaemia pattern. We recommended implementation of measuring serum cobalamin and subsequent HoloTC for indeterminate cases as a routine interval investigation in patients with NET. This is especially important if they have one or more risk factors. Further evaluation such as national audit of practice of B12 and other micronutrient deficiency such as iron, zinc, vitamin D is also recommended.