Endocrine Abstracts

Background: Patients with neuroendocrine neoplasms (NENs) may often develop other malignancies. This study aimed to identify the frequency at which these second non-NEN malignancies occurred in England.

Methods: Data was extracted from the National Cancer Registration and Analysis Service (NCRAS) on all patients diagnosed with a NEN at one of eight NEN site groups between 2012-2018: appendix, caecum, colon, lung, pancreas, rectum, small intestine and stomach. WHO International Classification of Disease edition 10 (ICD-10) codes were used to identify patients who had been diagnosed with an additional non-NEN cancer. Descriptive tables were produced to characterise the study cohort. Standardised incidence ratios (SIRs) for tumours diagnosed after the index NEN were produced for each non-NEN cancer type by sex and site.

Results: A total of 20,579 patients were included in the study. Overall, 3,127 patients were diagnosed with a non-NEN cancer at any time point, of which 19% were diagnosed after NEN, 70% prior to NEN and 11% on the same date. All NEN sites were associated with an increased rate of at least one non-NEN cancer. The most commonly occurring non-NEN cancers after NEN diagnosis were prostate (20%), lung (20%) and breast (15%). Statistically significant SIRs were observed for non-NEN cancer of the lung (SIR=1.85, 95%CI:1.55-2.22), colon (SIR=1.78, 95%CI:1.40-2.27), prostate (SIR=1.56, 95%CI:1.31-1.86), kidney (SIR=3.53, 95%CI:2.72-4.59) and thyroid (SIR=6.31, 95%CI:4.26-9.33). When stratified by sex, statistically significant SIRs remained for lung, renal, colon and thyroid tumours. Additionally, females had a statistically significant SIR for stomach cancer (2.65, 95%CI:1.26-5.57) and bladder cancer (SIR=2.61, 95%CI:1.36-5.02).

Conclusion: This study found that patients with a NEN experienced a metachronous tumour of the lung, prostate, kidney, colon and thyroid at a higher rate than the general population of England. There was no clear pattern between the site of NEN and subsequent non-NEN tumour site. Based on our findings we would suggest screening for second cancers using one of the many imaging or biochemical methods available for these and taking care to counsel all NEN patients on risk of second tumours. Surveillance and engagement in screening programmes is required to enable earlier diagnosis of second non-NEN tumours.