Endocrine Abstracts

Background: When seeing patients with gastroenteropancreatic neuroendocrine tumours (GEP-NETs) in clinic, we noticed that a significant proportion of our patients also had additional primary malignancies. This observation was also raised by patients at our local NET Patient Foundation support group. The idea that patients with GEP-NETs are more prone to additional malignancies is supported in the literature therefore we wanted to determine the proportion of our patients who have had an additional primary malignancy alongside their NET.

Aims: To determine the association of other primary malignancies with GEP-NETs in our cohort of patients.

Methods: We searched for all patients discussed at our NET MDT with GEP-NETs from 16 January 2018 to 17 September 2019. Electronic patient records were searched for evidence of diagnoses of additional malignancies in addition to their diagnosis of NET.

Results: 217 individual patients with GEP-NETs were discussed at our NET MDT between 16/1/2018 and 17/9/2019. Insufficient clinical data were available for 17 patients as they were being managed by different NHS trusts. 8 patients had the Multiple Endocrine Neoplasia 1 syndrome. Of the remaining 192 patients, 30 patients (15.6%) had evidence of an additional primary malignancy with 3 of these patients having 2 additional primary malignancies on top of their NET. The most common was prostate (N=9); followed by breast and lymphoma (N=4); renal (N=3); bladder (N=2); then colorectal, lung, thyroid, melanoma, myeloma, oesophageal, pancreatic, ovarian, GIST, myelofibrosis and Bowen’s disease (all N=1).

Discussion: The proportion of our patients who have an additional malignancy is similar in proportion to that reported in the literature and supports the evidence that patients with NETs are at risk of having additional primary malignancies. Our data also shows that a minority of patients are at risk of having 2 additional primary malignancies in addition to their NET. We would suggest that patients with an additional primary malignancy on top of their NET should be considered for genetic testing to look for tumour predisposition syndromes which may affect family members.