Second Primary Malignancies in Patients with a Neuroendocrine Neoplasm in England

INTRODUCTION: Patients with neuroendocrine neoplasms (NENs) may often develop other malignancies. This study aimed to identify the frequency at which these second malignancies occurred in England. METHODS: Data were 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 and 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. Standardized 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. The most commonly occurring non-NEN cancers after NEN diagnosis were the 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 the 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. Surveillance and engagement in existing screening programmes are required to enable earlier diagnosis of second non-NEN tumours in these patients.