Incidence of paraneoplastic antibodies in United Kingdom – An estimate from a regional centre

Background: A paraneoplastic neurological syndrome (PNS) describes the neurological complications of a malignancy that are not due to local or metastatic effects. PNS are often associated with the presence of serum paraneoplastic neuronal antibodies (PNAb). However, the frequency of identification of PNAb in hospitals and laboratories is rarely reported. This information will help plan and deliver diagnostic and clinical services. Objectives: To review the frequency, type and association with cancer of PNAb in a tertiary neurological centre over 9 years. Design: Retrospective observational study in an adult and paediatric population. Setting: Walton Centre NHS Foundation Trust (WCFT), Liverpool, United Kingdom. Patients: Patients seen at the WCFT who tested positive for PNAb with a ‘high risk’ for cancer (HR PNAb) from April 2012 - April 2021. Main outcome measures: Antibodies detected, neurological diagnosis, presence of cancer. Results: 1.6 % (107/6863) of the samples tested were positive for HR PNAb. We estimate the incidence of patients with HR PNAb seropositivity in the population to be 3.8/million/year. 20/33 patients for whom clinical details were available were found to have an associated malignancy. Crucially it was the initial detection of ‘high risk’ antibodies that led to the search and subsequent detection of cancer in 10 of the patients in this study. Conclusion: This is the first UK study to provide an estimated minimum incidence rate of HR PNAb from a defined geography and population. The inclusion of intermediate and low risk antibodies will make this number even higher. PNAb testing remains a vital investigation in neurology and for the early detection of cancer.