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Pancreatic Neuroendocrine Tumours (pNETs): Symptoms, Treatment & Surgical Procedures

Dr Thng Yongxian

Pancreatic Cancer Specialist & Surgeon
Hepatopancreatobiliary & General Surgeon
MBBS • MMed • MRCS (IRE) • FRCSED • FAMS

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  1. What is a Pancreatic Neuroendocrine Tumour (pNET)?
  2. Functional vs Non-Functional pNETs
  3. Grading & the Ki-67 Index
  4. Symptoms of pNETs
  5. Diagnosis & Staging
  6. Surgical Treatment Options
  7. When Is Surgery Recommended?
  8. Insurance & MediSave Coverage
  9. Frequently Asked Questions (FAQ)
  10. References

What Are Pancreatic Neuroendocrine Tumours (pNETs)?

A diagnosis involving the pancreas can be alarming. However, not all pancreatic tumours are the same.

 

If your scans or biopsy have identified a pancreatic neuroendocrine tumour (pNET), it is important to understand that this condition differs from the more common type of pancreatic cancer known as pancreatic adenocarcinoma. The way pNETs behave, how they are treated and their long-term outlook can be very different.

 

Pancreatic neuroendocrine tumours develop from hormone-producing cells within the pancreas. Because they arise from a different type of cell, they are classified separately from other pancreatic cancers and often respond to treatments that would not typically be used for pancreatic adenocarcinoma.

 

Many pNETs grow slowly, especially when diagnosed at an early stage. Treatment may involve surgery, targeted therapies or careful monitoring, depending on the tumour’s size, grade, location and whether it has spread.

Overview: A pancreatic neuroendocrine tumour (pNET) is a rare tumour that develops from the hormone-producing cells of the pancreas. Unlike the more common type of pancreatic cancer, pNETs often grow more slowly and may have a better outlook when diagnosed early.

Functional vs Non-Functional pNETs

One of the first things doctors determine is whether the tumour is producing excess hormones.

 

Some pNETs release hormones into the bloodstream and cause noticeable symptoms. These are known as functional pNETs. Others do not produce hormones that cause symptoms and may only be discovered incidentally during imaging performed for another reason. These are known as non-functional pNETs.

Functional pNETs: Driven by Hormone Production

Tumour Type Hormone Produced Key Symptoms Notes
Insulinoma Insulin Low blood sugar, sweating, dizziness, confusion, fainting Most common functional pNET. Usually small, solitary and benign. Surgery highly effective.
Gastrinoma Gastrin Recurrent stomach ulcers, acid reflux, diarrhoea May occur in pancreas or duodenum. Higher malignancy risk than insulinoma.
Glucagonoma Glucagon Weight loss, anaemia, diabetes, necrolytic migratory erythema (skin rash) Rare. Often larger at diagnosis.
VIPoma Vasoactive intestinal peptide (VIP) Severe watery diarrhoea, dehydration, low potassium Most occur in tail of pancreas.
Somatostatinoma Somatostatin Diabetes, gallstones, fatty stools Among the rarest functional pNETs.

Non-Functional pNETs: Silent but Significant

Non-functional pNETs do not cause symptoms through hormone production. As a result, many are discovered incidentally during CT or MRI scans performed for unrelated conditions.

 

Although the absence of symptoms can be reassuring, these tumours are sometimes diagnosed at a larger size because they may have been growing unnoticed for some time. This makes accurate staging particularly important when deciding on treatment.

Illustration of the pancreas highlighting neuroendocrine tumour location
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Understanding Aggressiveness: The Ki-67 Index & WHO Grading

Not all pancreatic neuroendocrine tumours behave in the same way. Some grow very slowly over many years, while others are more aggressive and require earlier treatment.

 

To better understand how a tumour is likely to behave, doctors look at its grade. One of the most important measurements used is the Ki-67 index, which estimates how quickly tumour cells are dividing.

Grade Ki-67 Index Growth Rate Typical Approach
Grade 1 (G1) 3% Slow Surveillance or limited surgery in selected cases
Grade 2 (G2) 3 – 20% Intermediate Closer follow-up or formal pancreatic resection
Grade 3 (G3) 20% Fast Surgery combined with systemic therapy; multidisciplinary review

Tumour grade plays an important role in determining the most appropriate treatment approach.

 

A small, low-grade insulinoma may be suitable for surveillance or limited surgery, while a larger or higher-grade tumour may require formal pancreatic resection and multidisciplinary review.

 

For some Grade 3 tumours, treatment may involve medical oncology input as part of the treatment planning process, with surgery considered where appropriate.

 

For this reason, treatment recommendations are guided not only by the size and location of the tumour, but also by a careful assessment of its biological behaviour before any surgical decision is made.

Symptoms of Pancreatic Neuroendocrine Tumours

Symptoms vary widely depending on whether the pNET is functional or non-functional. Functional tumours often cause hormone-related symptoms that prompt investigation, while non-functional pNETs may produce no symptoms until the tumour reaches a significant size.

  • Hypoglycaemia Episodes
    Sweating, dizziness, confusion or fainting, particularly after fasting: characteristic of insulinoma.
  • Recurrent Peptic Ulcers or Acid Reflux
    Persistent stomach ulcers and abdominal discomfort, often associated with gastrinoma.
  • Unexplained Weight Loss or Loss of Appetite
    Significant unintentional weight loss and, in some cases, a characteristic skin rash known as necrolytic migratory erythema: both associated with glucagonoma.
  • Severe Watery Diarrhea
    Profuse diarrhoea leading to dehydration, associated with VIPoma.
  • Abdominal Mass or Pain
    Larger non-functional tumours may present as a palpable abdominal mass or persistent pain.
  • Incidental Finding on Imaging
    Many non-functional pNETs are discovered during CT or MRI scans performed for unrelated reasons.

Diagnosis & Staging

Accurate staging is essential because treatment decisions depend not only on where the tumour is located, but also on how extensive the disease is and whether it has spread beyond the pancreas.

 

Diagnosis usually involves a combination of blood tests, imaging studies and tissue biopsy.

Method Purpose Notes for pNET
Blood/Urine Biomarkers Identify hormone excess; monitor disease Chromogranin A (CgA); also insulin, gastrin, glucagon, VIP depending on suspected type
CT Scan First-line anatomical imaging Assess tumour size, location, vascular involvement, distant spread
MRI Additional anatomical detail Particularly useful for small pancreatic lesions and liver metastases
Ga-68 DOTATATE PET/CT Functional imaging specific to NETs Detects small tumours and distant disease missed by CT/MRI. Determines PRRT eligibility. Available at major hospitals in Singapore.
Endoscopic Ultrasound (EUS) & Biopsy Tissue confirmation and Ki-67 grading Ultrasound probe passed through stomach; needle biopsy confirms NET origin and grade

Surgical Treatment Options for Pancreatic Neuroendocrine Tumours

Surgery remains the main treatment for many localised pancreatic neuroendocrine tumours. The most appropriate operation depends on the tumour’s size, location, grade and relationship to important structures within the pancreas.

Procedure Tumour Location What Is Removed Minimally Invasive Option
Enucleation Small, low-grade tumours away from main pancreatic duct Tumour only, pancreas preserved Yes, in selected cases
Distal Pancreatectomy Body or tail of pancreas Body and tail of pancreas; may include spleen Yes (laparoscopic or robotic)
Whipple Procedure (Pancreaticoduodenectomy) Head of pancreas (when enucleation not suitable) Head of pancreas, duodenum, gallbladder, part of bile duct; digestive tract reconstructed Selected patients
Metastatic Disease Surgery Liver metastases present Debulking of hepatic spread in selected patients Case-dependent

Laparoscopic and robotic surgical techniques may be suitable for selected patients. Potential benefits include smaller incisions, reduced pain, shorter hospital stays and faster recovery. However, suitability depends on factors such as tumour size, location and involvement of nearby structures.

Even when a pNET has spread to the liver, surgery may still play a role in selected patients. Reducing tumour burden can improve symptoms in functional tumours and may contribute to longer-term disease control in carefully selected cases.

 

These decisions are typically made within a multidisciplinary team involving surgeons, oncologists, radiologists and nuclear medicine specialists.

 

For patients who are not suitable for surgery, additional options may include PRRT, targeted therapies or liver-directed treatments. See our pancreatic cancer overview for further context on integrated treatment approaches.

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When Is Surgery Recommended for Pancreatic Neuroendocrine Tumours?

Surgery is not always the first or only answer for a pNET diagnosis. The decision to operate depends on several factors, including tumour size, grade, location and whether the tumour is causing symptoms.

 

For functional tumours causing significant symptoms, surgery is often recommended to remove the source of hormone excess. For small, incidentally discovered non-functional Grade 1 tumours under 2 cm, careful surveillance may be a reasonable initial approach in selected patients.

 

For larger tumours, higher-grade lesions, or those involving nearby structures, pancreatic resection is often recommended. Tumours located in the head of the pancreas may require a Whipple procedure, while tumours in the body or tail are typically managed with other forms of pancreatic resection.

 

The most appropriate treatment approach is determined based on the tumour’s characteristics, pathology, imaging findings, and overall clinical context.

Insurance & MediSave Coverage in Singapore

Understanding the financial aspects of treatment is an important part of planning your care. Dr Thng’s clinic assists patients with cost estimates, insurance documentation and pre-authorisation where required.

Scheme Coverage Notes
MediSave Eligible inpatient surgical procedures Available to Singapore Citizens and Permanent Residents, subject to MOH regulations and withdrawal limits
Integrated Shield Plans (ISPs) Private hospital pancreatic surgery Covers treatment at Mount Elizabeth and Gleneagles. Coverage depends on policy type, rider, panel arrangements and pre-authorisation. Dr Thng's team can assist.
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Dr Thng Yongxian, colorectal and general surgeon at private clinic Singapore

The specialist leading your care

Dr Thng Yongxian

Medical Director, Senior Consultant Pancreas & Hepatobiliary Surgeon

MBBS (SG) • MMed (Surg) • MRCS (Ire) • FRCSEd (Gen) • FAMS (Surg)

Dr Thng Yongxian is a fellowship-trained HPB and general surgeon with specialised training in minimally invasive and complex abdominal surgery. He previously served as Clinical Lead for HPB Surgery at NTFGH and has extensive experience managing conditions of the liver, gallbladder, pancreas and bile ducts, including pancreatic cancer surgery such as the Whipple procedure (pancreaticoduodenectomy) and pancreatectomy.

In addition to pancreatic cancer surgery, Dr Thng performs advanced laparoscopic procedures and has contributed to national initiatives, including serving on the Ministry of Health Laparoscopic Cholecystectomy Clinician Workgroup for value-driven care. 

 

His surgical work has been presented at international conferences, reflecting ongoing engagement in clinical practice and surgical education.

 

Patients under his care receive careful evaluation and individualised treatment planning based on their clinical condition and overall health.

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Extensive experience in minimally invasive abdominal procedures.

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Care delivered with careful surgical planning and risk assessment.

Timely Access to Care

Credentialed at major private hospitals, with coordinated scheduling for consultations and procedures

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Assistance with documentation and insurance processes where applicable.

Frequently Asked Questions

Is a pNET the same as pancreatic cancer?

No. Pancreatic neuroendocrine tumours are different from pancreatic adenocarcinoma, the more common form of pancreatic cancer. They arise from different cells within the pancreas and often behave very differently, with many pNETs growing slowly and having more favourable long-term outcomes.

A small proportion of pNETs are associated with inherited conditions such as Multiple Endocrine Neoplasia Type 1 (MEN1). If a genetic predisposition is suspected, Dr Thng may recommend referral for genetic counselling.

Outcomes depend on the tumour’s grade and stage at diagnosis. Many localised Grade 1 and Grade 2 pNETs have favourable long-term outcomes, particularly when treated early. Dr Thng can provide personalised information based on your specific clinical findings.

Peptide Receptor Radionuclide Therapy (PRRT) is an advanced treatment that delivers targeted radiation to neuroendocrine tumour cells. It may be considered for selected patients whose tumours express somatostatin receptors, as confirmed by Ga-68 DOTATATE PET/CT. PRRT is available at major tertiary hospitals in Singapore.

Both are minimally invasive approaches that typically offer faster recovery and smaller incisions compared with open surgery. Robotic surgery provides enhanced three-dimensional visualisation and instrument precision, which may be advantageous in selected complex cases.
 
Many patients can utilise MediSave and Integrated Shield Plan benefits for eligible inpatient surgical treatment. Coverage varies according to the individual’s policy and insurer. Dr Thng’s team can assist with cost estimates and pre-authorisation.
 
Follow-up schedules vary depending on the tumour grade and pathology findings. Most patients require regular imaging and long-term surveillance after treatment, as some pNETs can recur even years later.
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 Treatment decisions should be tailored to each patient. Arrange a consultation for a personalised assessment

References:

  1. Falconi M, et al. ENETS Consensus Guidelines Update for the Management of Patients with Functional Pancreatic Neuroendocrine Tumors and Non-Functional Pancreatic Neuroendocrine Tumors. Neuroendocrinology. 2016;103(2):153–171.
  2. Pavel M, et al. Gastroenteropancreatic Neuroendocrine Neoplasms: ESMO Clinical Practice Guidelines. Annals of Oncology. 2020;31(7):844–860.
  3. Dasari A, et al. Trends in the Incidence, Prevalence and Survival Outcomes in Patients with Neuroendocrine Tumors in the United States. JAMA Oncology. 2017;3(10):1335–1342.
  4. Cloyd JM, et al. Surgical Management of Pancreatic Neuroendocrine Tumors. Surgical Oncology Clinics of North America. 2020;29(2):293–312.
  5. National Cancer Centre Singapore. Neuroendocrine Tumours. Available at: nccs.com.sg [Accessed June 2026].

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Nexus Surgical @ Mt. Elizabeth Orchard

Nexus Surgical @ Mt. Elizabeth Novena

Nexus Surgical @ Parkway East

Nexus Surgical @ Gleneagles Medical Centre

Nexus Surgical @ Mt. Alvernia

Nexus Surgical @ Mt. Elizabeth Orchard

Nexus Surgical @ Mt. Elizabeth Novena

Nexus Surgical @ Parkway East

Nexus Surgical @ Gleneagles Medical Centre

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