Endocrine Abstracts

Background: Neuroendocrine tumours (NETs) are a heterogenous group of slow growing tumours with an increasing incidence. Disease-related diarrhoea, surgery and medical treatment can lead to malabsorption, resulting in vitamin deficiencies.

Objective: To establish the prevalence of vitamin deficiencies in patients with NETs.

Method: Retrospective review of NET patients seen since 2014 in South Wales across 6 health boards. Deficiencies in vitamin and micronutrients were identified on blood results at any time since NET diagnosis.

Results: 260 NET patients (120 females, 140 males; median age 69 years). Grades I, II and III detected in 61.9, 21.5, and 1.5% of patients, respectively. Metastasis present in the lymph nodes in 123(47.3%) and the liver in 94(46.2%) patients. Vitamin and micronutrient deficiencies were present in gastroenteropancreatic NETs, particularly in those with a midgut primary. Deficiencies were noted in Vitamin B12(27%), A(9%), D(28%), E(1%), iron(ferritin 17%), folate(11%), selenium(4%), zinc(10%), and copper(1%). Vitamin B12 was present in 45(32.4%) of those with a small bowel resection. 76(49.4%) patients on somatostatin analogue therapy experienced steatorrhea of which 41(53.9%) developed fat-soluble vitamin deficiencies.

Conclusion: Vitamin and micronutrient deficiencies are present in gastroenteropancreatic NETs and may be a consequence of various factors including previous NET surgery, or treatment with somatostatin analogues (causing pancreatic enzyme insufficiency) or the NET itself. Vitamin D deficiency may relate to the background deficiency in the population. Some of these may require monitoring as part of NET care.

Key words: neuroendocrine tumour, vitamin, micronutrient, deficiency