Endocrine Abstracts

We present a series of patients with Neuroendocrine Tumours (NETs) highlighting potential nutritional deficiencies in this patient group.

Case-1: Mr.B, a 59-year-old gentleman, with well-differentiated, Grade-2, metastatic NET and carcinoid-syndrome diagnosed in August-2023. He had a history of heavy alcohol use. He started treatment with Sandostatin-Analogues (SAs) but struggled due to low sub-cutaneous fat, switching to Octreotide continuous infusion. At clinic review, he was non-compliant with treatment, becoming depressed, paranoid and confused. On examination he had a dry, scaly, erythematous rash over the dorsum of his hands. Pellagra (Vitamin-B3 deficiency) was suspected. Mr.B was treated with Pabrinex followed by Vitamin-B Co-Strong. His confusion improved.

Case-2: Mr.A, a 68-year-old gentleman was diagnosed in 2014 with metastatic, well-differentiated, Grade-1, small-bowel NET being treated with SAs for 3-years with stable disease. He had bile acid diarrhoea from previous ileocaecal resection and cholecystectomy and was prescribed cholestyramine. He started noticing blurring of vision particularly in low light conditions. Vitamin-A levels were checked and found to be low. He was started on Vitamin-A supplements and vision improved.

Case-3: Mrs.K, a 57-year-old woman with Grade-2, metastatic, mid-gut NET diagnosed in September-2021 and treated with SAs for 3-years with stable disease. Mrs.K, however, was experiencing progressively worsening steatorrhoea. Routine blood tests were taken for fat-soluble vitamins and showed low Vitamin-K. On direct questioning, patient reported easy bruising. Diet modification was initially tried, but Vitamin-K supplements were required.

Discussion: Pancreatic enzyme insufficiency is a common adverse-effect of SAs. This, in turn, can reduce absorption of fat-soluble vitamins such as Vitamins A,D,E and K. Patients at risk may experience steatorrhoea secondary to their SAs. The concurrent prolonged use of bile-acid sequestrants may further exacerbate fat soluble vitamin deficiency by disrupting fat-soluble vitamin absorption. These cases highlights the importance of managing steatorrhoea with pancreatic enzyme replacement and monitoring fat soluble vitamin levels so deficiencies can be detected early. Carcinoid-syndrome can also lead to nutritional deficiencies. Tryptophan is diverted for serotonin production instead of nicotinic acid leading to Vitamin-B3 deficiency. Patients with a history of alcohol excess are at particular risk due to associated malnutrition and impaired niacin metabolism.