Diagnosis and management of pancreatic neuroendocrine tumours

ONCOLOGY

Medical writer: Jin Ye Yeo | Last updated: 12 June 2026 | In: Oncology, Neuroendocrine Tumours, Endocrine Therapy

Article Keywords

pancreatic neuroendocrine tumour, treatment and management, diagnosis and prognosis, case study, risk factors, presentation of pancreatic neuroendocrine tumours

Prof Kenneth Chok (Department of Surgery, Faculty of Medicine, Chinese University of Hong Kong) and Dr Landon Chan (Department of Clinical Oncology, Faculty of Medicine, Chinese University of Hong Kong) shared their knowledge and expertise on the diagnosis and management of pancreatic neuroendocrine tumours (PNETs).

What are PNETs?

PNETs are rare tumours that originate from the endocrine islet cells of the pancreas, and present primarily as solid neoplasms.^1,2 PNETs account for less than 2% of all pancreatic cancers,³ with less than 100 cases observed at the Prince of Wales Hospital over the last 15 years.⁴ However, annual PNETs diagnoses are increasing, potentially due to enhanced surveillance, increased screening, and improved imaging qualities.³

Causes of PNETs

The exact aetiology of PNETs remains unclear, though risk factors such as hereditary syndromes (e.g. multiple endocrine neoplasia type 1 [MEN1]) and somatic mutations (e.g. MEN1, DAXX, and ATRX) play a role in their pathogenesis.⁵

While most PNETs are sporadic, rare cases are syndromic and linked to inherited syndromes⁶ such as von Hippel-Lindau syndrome or MEN1.^7,8 The Hong Kong Neuro-Oncology Society and Hong Kong Society of Uro-Oncology are collaborating to develop a joint consensus on early von Hippel-Lindau syndrome diagnosis, facilitated by the availability of effective disease-controlling medication.

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Presentation, diagnosis, and prognosis of PNETs

PNETs are broadly categorised as functional (hormone-secreting) or non-functional (non-hormone-secreting), and diagnosed based on imaging features, histology, and hormonal assessment.⁹

Majority of PNETs (60–90%) are non-functional, often detected incidentally or presenting as vague symptoms, such as epigastric pain when the tumour reaches a significant size.^5,9 Functional PNETs are less common, and account for ~18% of PNET cases at the Prince of Wales Hospital. Functional PNETs actively secrete hormones, hence most patients with these tumours have distinct clinical syndromes related to the secreted hormone,⁹ the most common being insulinoma, which arises from excessive secretion of exogenous insulin and leads to recurrent hypoglycaemia.^5,9

Prognosis of PNETs varies largely by tumour grade.¹⁰ Grade 1 PNETs (most common) has a favourable prognosis post-resection, with long-term survival and life expectancy similar to unaffected individuals. Grade 2 PNETs lack effective adjuvant treatments, so prognosis remains poorer than grade 1, and patients require post-resection surveillance. Grade 3 PNETs tend to be aggressive and metastatic, hence carry a significantly poorer outlook.

Treatment of PNETs

The management of PNETs is largely guided by tumour characteristics, such as grade, size, functionality, and location.¹¹

For patients with localised, functional, or early-stage PNETs, surgical resection is recommended to mitigate dangerous symptoms such as syncope.^11,12 Surgical resection yields excellent outcomes, with low recurrence rates and a 5-year overall survival rate of around 90% for early-stage disease.⁴ Exceptions are made in cases where patients have severe comorbidities, high surgical risk, extensive metastasis, or small, non-functional tumours.¹³ Surgical risks are particularly heightened when tumours are located in the pancreatic head, necessitating complex procedures such as a Whipple resection.¹³

For asymptomatic PNETs ≤2cm, guidelines remain controversial whether surgery should be the primary treatment approach.¹³ A general consensus advises conservative observation with interval scans for grade 1 tumours <1cm. For larger lesions, shared decision-making with the patient is recommended to explore either surgical resection or enucleation. Enucleation may be preferable if the tumour is located peripherally in the pancreas or not adjacent to the main pancreatic duct.¹³

In advanced or metastatic, low-to-intermediate grade PNETs, somatostatin analogues can alleviate functional symptoms and slow tumour growth.¹³ Where there is significant tumour burden, debulking surgery may be considered.¹³ Second-line options include everolimus, sunitinib, chemotherapy, and peptide receptor radionuclide therapy (PRRT).¹¹ With around 80% PNETs overexpressing somatostatin receptors, targeted PRRTs like Lutetium¹⁷⁷-DOTATATE can deliver localised radiation to tumour cells while sparing healthy tissue.¹⁴ Advanced or metastatic tumours can also be treated with chemotherapy.¹³

PNET requires multidisciplinary management

PNET is a rare and heterogeneous disease.⁵ The evolving landscape of oncology, coupled with advancements in surgical techniques, underscores the need for multidisciplinary care in managing PNETs.

Patient case study: A male with PNET showing malignant behaviour

A 42-year-old male, suspected of having adenocarcinoma with vascular encasement around the celiac trunk, underwent endoscopic ultrasound (EUS) and biopsy, revealing a grade 2, malignant PNET in 2023. With surgery excluded from the treatment options, the patient was ultimately treated with PRRT. The latest imaging dated 20 March 2025 showed no active disease (Figure 1).

Figure 1. Scans of patient on (a) 24 April 2023 and (b) 20 March 2025, showing no active disease.

Images courtesy of Prof Kenneth Chok

This demonstrates how modern therapies can effectively address even previously unresectable tumours, and highlights a paradigm shift: unresectability no longer equates to a fatal prognosis.

Diagnosis and management of pancreatic neuroendocrine tumours

Abbreviations: EUS, endoscopic ultrasound; MEN1, multiple endocrine neoplasia type 1; PNET, pancreatic neuroendocrine tumour; PRRT, peptide receptor radionuclide therapy.

References

National Cancer Institute. Available online. https://www.cancer.gov/types/pancreatic/patient/pnet-treatment-pdq. Last accessed: 12 May 2026.

Kumar T, et al. Autops Case Rep. 2020;10(3):e2020171.

Sonbol MB, et al. Oncologist. 2022;27(7):573–8.

Chan LL, et al. ESMO Gastrointest Oncol. 2026;11:100293.

Helbing A, et al. StatPearls. Available online. https://www.ncbi.nlm.nih.gov/books/NBK448121/. Last accessed: 5 January 2026.

Kwon GJ & Shi C. Semin Diagn Pathol. 2025;42(6):150946.

Coco D, et al. J Kidney Cancer VHL. 2023;10(2):13–20.

Geurts JL. J Gastrointest Oncol. 2020;11(3):559–66.

Hopper AD, et al. Frontline Gastroenterol. 2018;10(3):269–74.

Shyr BS, et al. Asian J Surg. 2022;45(12):2659–63.

Hofland J, et al. J Neuroendocrinol. 2023;35(8):e13318.

Karanth JB, et al. BMJ Case Rep. 2022;15(6):e249698

Akirov A, et al. Cancers (Basel). 2019;11(6):828.

Karimi A, et al. NPJ Precis Oncol. 2025;9(1):146.

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This article is not medical advice. Patients should seek personal assessment by a licenced specialist. Physicians are recommended to read the full publication(s) as cited in the article before making medical decisions. This article does not supersede nor replace the published article(s).