Endocrine Abstracts

Background: The University Teaching Hospital Trust has a regional neuroendocrine tumour (NET) service that requires a database exclusively for NET patient information. UK and Ireland NET Society (UKINETS) guidelines for gastroenteropancreatic (GEP) NETs recommend plasma Chromogranin-A (Cg-A) and 24 h urinary 5-hydroxyindoacetic acid (24 h Ur 5-HIAA) as baseline investigations. This audit investigated both guideline adherence and the value of these tests in making the diagnosis of GEP NETs.

Method: A retrospective dataset analysis was performed using clinical records (i.e. NET clinic letters and Multidisciplinary Team (MDT) forms) and the hospital’s software systems (online since 2004). NET patients’ details, including Cg-A and 24 h Ur 5-HIAA levels, were recorded onto the database.

Results: 56/101 (55.45%) patients under the NET service were diagnosed with GEP NETs by investigations including biopsy and imaging. 47/56 (83.93%) GEP NET patients had Cg-A levels and 15/47 (31.91%) had a significantly raised level (>150 pmol/l). 35/56 (62.50%) GEP NET patients had 24 h Ur 5-HIAA levels, 10/35 had significantly raised levels (>50 pmol/l) and 5/10 had symptoms of carcinoid syndrome. 3/35 (8.57%) confirmed GEP NET patients had symptoms of carcinoid syndrome and 24 h 5-HIAA levels below 50 pmol/l.

Discussion: 83.93% and 62.50% of GEP NET patients had documented Cg-A and 24 h Ur-5HIAA levels respectively. Therefore, UKINETS guideline adherence could be improved. The results show a false negative rate of 68.09 and 8.57% in Cg-A and 24 h Ur-5HIAA tests respectively suggesting these baseline tests are of limited use in diagnosing GEP NETs. However, confounding factors (e.g. sample size) might have influenced these findings. It was unclear whether patients with raised 24 h Ur 5-HIAA levels without symptoms of carcinoid syndrome was due to incomplete records or because they were asymptomatic. Clinic and MDT letter templates were recommended to rectify this and a future re-audit is required to confirm quality improvement.