Aims:
To explore the evolving epidemiology and investigate outcomes in current management of appendiceal neuroendocrine tumours (A-NETs) among Queensland patients’ aged under 50 years.
Methods:
This retrospective population-based study used clinical and treatment data from the Queensland Oncology Repository, a comprehensive repository which contains demographic, diagnosis, and treatment data on Queenslanders diagnosed with cancer. The study cohort included all cases (n = 659) of A-NETS in patients aged < 50 years diagnosed from 2000 to 2017 (ICDO3 histology code 8240/3, 8249/3). Incidence rates were directly standardised to the 2001 Australia population distribution. Multivariable logistic regression was used to identify factors independently associated with likelihood of undergoing colon resection compared to appendicectomy only.
Results:
Annual incidence of A-NET in Queensland increased by 5.5% (95% CI = 3.4%-7.7%) over the study period (2000 -2017), with mortality remaining very low with no deaths attributable to A-NETs. Median age at diagnosis was 26 years (range 6-49) and 62.5% were female. Most patients (n= 560) underwent one surgical procedure only, and the remaining 99 underwent two procedures. For the patients who underwent initial appendicectomy (n=640), only a minority (n = 92, 14.4%) went onto right hemicolectomy. In the fully adjusted model, the strongest predictors of colon resection following appendicectomy were involvement of margins (OR = 29.6, CI 8.85 – 98.72) and tumour size >= 20mm (OR = 19.35, CI 8.75 - 42.79).
Conclusions:
This study, including data from 17 years, found significantly increasing rates of A-NETs. It also suggests patients with involved margins and large tumour size are more likely to have a follow-up colonic resection. The high survival of patients with A-NETs is reassuring and reinforces current practice but may suggest overtreatment with bowel resection for some patients.