A “Watch and Wait” Strategy Involving Regular Endoscopic Surveillance Is Safe for Many Patients with Small, Sporadic, Grade 1, Non-Ampullary, Non-Functioning Duodenal Neuroendocrine Tumours

Abstract

<b><i>Introduction:</i></b> Duodenal neuroendocrine tumours (d-NETs) are rare but are increasing in incidence. Current ENETS guidelines advocate resection of all localized d-NETs. However, “watch and wait” may be appropriate for some localized, small, grade 1, non-functioning, non-ampullary d-NETs. We evaluated whether patients with such d-NETs who chose “watch and wait” involving regular endoscopic surveillance had equivalent disease-related outcomes to patients undergoing endoscopic or surgical resection. <b><i>Methods:</i></b> Retrospective review of patients with histologically confirmed d-NETs at Liverpool ENETS Centre of Excellence 2007–2020. <b><i>Results:</i></b> Sixty-nine patients were diagnosed with d-NET of which 50 were sporadic, non-functioning, non-ampullary tumours. Patient treatment groups were similar in terms of age, gender, and tumour location and grade, but unsurprisingly, larger tumours (median diameter 17 mm [<i>p</i> < 0.0001]) were found in the surgically treated group. Five patients underwent surgical resection with no evidence of tumour recurrence or disease-related death. Twelve patients underwent endoscopic resection (ER), with 1 local recurrence detected during follow-up. Thirty patients (28 with d-NETs ≤10 mm) underwent “watch and wait” with resection only if tumours increased in size. The d-NETs in 28/30 patients remained stable or decreased in size over a median 27 months (IQR: 15–48, <i>R</i>: 3–98). In 7 patients, the d-NET was completely removed by avulsion during diagnostic biopsy and was not seen at subsequent endoscopies. Only 2 patients showed increased d-NET size during surveillance, of whom only one was fit for ER. No NET-related deaths were documented during follow-up. <b><i>Conclusions:</i></b> All of the localized, ≤10 mm, grade 1, non-functioning, non-ampullary d-NETs in this cohort behaved indolently with very low risks of progression and no tumour-related deaths. “Watch and wait,” therefore, appears to be a safe alternative management strategy for selected d-NETs.

Duodenal neuroendocrine neoplasms with unexpectedly aggressive behaviour: Challenging the “watch and wait” approach

“…Based on these findings, a "watch and wait" approach was recommended for ≤ 10 mm, non-functional, non-ampullary, grade 1 duodenal NENs. 3 Despite the above published data, for both of the cases described in the present study, the tumours were non-functional and non-ampullary, and measured between 4 and 5 mm, with a low Ki-67 index (< 5%) at the time of diagnosis, but demonstrated an unexpectedly aggressive behaviour.…”

“…1,9,11 Nevertheless, endoscopic tumour resections could be associated with complications such as bleeding and perforation. 3,9 However, there is some evidence in the literature regarding the indolent nature of < 10 mm, non-functional, non-ampullary NENs.…”

“…7 Peri-ampullary NENs are associated with a poorer prognosis. 1,3 In this case series, we describe two cases of well differentiated, low grade (Ki-67; 1%-5%) neuroendocrine tumours measuring < 10 mm at the time of diagnosis, but demonstrating an aggressive course during follow-up. Furthermore, we also summarise the available therapeutic strategies for the management of small, grade 1, non-functioning, non-ampullary duodenal neuroendocrine neoplasms.…”

“…1 Furthermore, the overall incidence of the duodenal NENs has increased during recent years 2 and this is largely attributed to technical advances and the availability of endoscopy. 2,3 These tumours have a heterogeneous nature in relation to their functionality, location and tumour behaviour/prognosis. 1 Apart from factors such as primary tumour size, Ki-67 index/mitotic count, 1,4 presence of regional involvement and distant metastases, the overall prognosis of duodenal NENs is also dependent on the presence of invasion of muscularis mucosa and its location in the duodenum.…”

“…1 Apart from factors such as primary tumour size, Ki-67 index/mitotic count, 1,4 presence of regional involvement and distant metastases, the overall prognosis of duodenal NENs is also dependent on the presence of invasion of muscularis mucosa and its location in the duodenum. 1,3,4 The majority (75%) of tumours measure < 20 mm at diagnosis 1,[4][5][6][7] and are usually limited to the submucosa and the mucosa, 1 whereas 90% of them are non-functional. 7 Peri-ampullary NENs are associated with a poorer prognosis.…”