Background: Neuroendocrine tumours are rare tumours that arise from neuroendocrine cell types which are widespread throughout the body. These tumours can develop in many different organs and secrete a variety of hormones making biochemical monitoring of treatment/progression challenging. Previously patients at Beatson West of Scotland Cancer Centre were monitored using either a full gut hormone profile (GHP) or chromogranin A and B (CGs) measured at Charing Cross Hospital. A new chromogranin A (CgA) service was introduced in Scotland in September 2018 using the CisBio ELISA assay. Patients undergoing monitoring initially had paired analysis due to the expected variation between assays. This audit aims to identify the most appropriate marker for ongoing follow-up on an individual patient basis.
Method: Seven months of data was extracted from the laboratory system to include all requests for local CgA, GHP, and CGs. Patients were included if they had two paired samples within this time period. Clinical details were collated from the clinical portal system to include where available type of tumour, treatment and imaging results.
Results: Forty one patients were identified; nine patients with pancreatic tumours were excluded as the local protocol in this group is full GHP. Of the 32 remaining patients, 69% could be monitored using the local CgA assay. A group of patients still require monitoring by the Charing Cross assay, 12.5% are CgB secretors only and 9% have normal local CgA but abnormal CGs. The remaining 9% have discordant results between assays and more paired data is required before a decision is made.
Conclusion: The new local CgA assay is a useful marker for follow up in 69% of patients. Individualisation of monitoring can improve patient care and cost effectiveness.