Gastroenteropancreatic neuroendocrine tumours represent a group of rare but increasingly recognised cancers that develop in hormone-producing cells throughout the digestive system and pancreas. While these tumours often grow slowly, their treatment requires a carefully planned approach that combines various medical strategies tailored to each person’s unique situation.

Navigating Treatment Options for Gastroenteropancreatic Neuroendocrine Tumours

When someone receives a diagnosis of gastroenteropancreatic neuroendocrine tumour disease, understanding the treatment landscape becomes essential. The main goal of treatment is not simply to remove or shrink the tumour, but to control symptoms, maintain quality of life, and slow disease progression. Each person’s treatment plan depends on several factors, including where the tumour is located, whether it produces excess hormones, how fast it is growing, and whether it has spread to other parts of the body.^[3]

Treatment decisions involve collaboration between specialists in multiple disciplines, including medical oncologists, surgeons, radiologists, and endocrinologists. This team approach ensures that every aspect of the disease is addressed, from hormone-related symptoms to tumour growth patterns. Medical societies have developed standard treatment guidelines based on years of research and clinical experience, and these recommendations form the foundation of care. At the same time, ongoing research continues to explore new therapies through clinical trials, offering hope for more effective treatments in the future.^[3]

The treatment approach varies significantly depending on the stage of disease at diagnosis. Some people are diagnosed when the tumour is still localised and can potentially be removed completely with surgery. Others may have disease that has already spread, requiring a combination of treatments to manage symptoms and control tumour growth. The disease stage, along with the tumour grade (which indicates how quickly cells are dividing), helps doctors predict how the disease might behave and which treatments are most likely to be effective.^[9]

Standard Approaches to Managing These Tumours

Surgery remains the primary treatment option for localised gastroenteropancreatic neuroendocrine tumours that can be safely removed. When the tumour is confined to one area and has not spread extensively, surgical removal offers the best chance for long-term control or even cure. The type of surgery depends on where the tumour is located. For tumours in the small intestine, surgeons may remove the affected section of bowel. Pancreatic tumours may require removal of part or all of the pancreas. Even when complete removal is not possible, surgery may still help reduce symptoms by decreasing the amount of tumour tissue present.^[9]

Many people with gastroenteropancreatic neuroendocrine tumours receive treatment with somatostatin analogues, which are synthetic versions of a natural hormone that helps regulate various bodily functions. These medications, which include substances known as octreotide and lanreotide, work by binding to specific receptors on tumour cells. They can help control symptoms caused by excess hormone production, such as severe diarrhoea, flushing, and abdominal pain. Beyond symptom control, somatostatin analogues may also slow tumour growth in some cases. These medications are typically given as injections every few weeks and are generally well tolerated, though they can cause side effects such as digestive upset, gallstones, or changes in blood sugar levels.^[3][9]

For more advanced disease, targeted biological agents have transformed treatment possibilities. Two medications that have shown benefit are everolimus and sunitinib. Everolimus works by blocking a protein pathway called mTOR (mammalian target of rapamycin), which cancer cells use to grow and multiply. By interrupting this pathway, everolimus can slow tumour progression. Sunitinib, on the other hand, is an angiogenesis inhibitor, meaning it interferes with the formation of new blood vessels that tumours need to grow. These medications are taken as daily pills and have become important options for people whose disease continues to progress despite other treatments.^[3][11]

Chemotherapy plays a role in treating certain types of gastroenteropancreatic neuroendocrine tumours, particularly those that are rapidly growing or poorly differentiated. Traditional chemotherapy drugs work by damaging cancer cells’ ability to divide. For pancreatic neuroendocrine tumours, a combination of drugs called capecitabine and temozolomide has shown promise. These oral medications are often given in cycles, with periods of treatment followed by rest periods to allow the body to recover. Other chemotherapy combinations used include streptozocin with fluorouracil or doxorubicin. The choice of chemotherapy depends on the tumour’s location, grade, and how aggressively it is growing.^[3][11]

A specialised treatment called peptide receptor radionuclide therapy has emerged as an important option for certain patients. The most commonly used form involves a substance called lutetium-177 DOTATATE, which combines a radioactive element with a molecule that seeks out and binds to somatostatin receptors on tumour cells. Once attached, the radioactive component delivers targeted radiation directly to the cancer cells while sparing most healthy tissue. This treatment is particularly useful for tumours that show high uptake on somatostatin receptor imaging scans. People receive this therapy as an infusion given several times over a period of months. It can effectively shrink tumours and control symptoms in many patients.^[11]

For people with tumours that have spread to the liver, interventional radiology procedures offer additional treatment options. These minimally invasive techniques include hepatic artery embolisation, where doctors block blood vessels feeding the tumour, and radiofrequency ablation, where heat energy destroys tumour tissue. Because the liver receives most of its blood supply from the hepatic artery while tumours rely heavily on this blood source, blocking these vessels can selectively starve the cancer cells. These procedures are performed by specialised radiologists and may be repeated if needed.^[3]

Treatment duration varies widely depending on the approach used and how the disease responds. Some people continue on somatostatin analogues or targeted therapies for years as long as they remain effective and tolerable. Others may receive treatment in defined courses, such as with chemotherapy cycles or peptide receptor radionuclide therapy sessions. Regular monitoring through imaging scans, blood tests, and symptom assessments helps doctors determine when to continue, change, or pause treatment.^[9]

Investigational Therapies Being Studied in Clinical Trials

Clinical trials represent the frontier of treatment advances for gastroenteropancreatic neuroendocrine tumours. These carefully designed research studies test new drugs, combinations of treatments, or novel approaches to determine if they are safe and effective. Participation in clinical trials can provide access to promising therapies before they become widely available, while also contributing to medical knowledge that may help future patients.^[3]

Phase I clinical trials focus primarily on safety. Researchers carefully test a new drug or treatment approach in a small group of people to determine the safest dose range and identify any serious side effects. These trials help establish how the body processes the medication and what dose should be used in later studies. While phase I trials are mainly about safety, researchers also watch for signs that the treatment might be working.^[3]

Phase II trials expand testing to a larger group of patients to evaluate how well the treatment works. These studies measure whether tumours shrink, whether disease progression slows, and whether symptoms improve. Phase II trials continue to collect safety information while focusing more on efficacy. If a treatment shows promise in phase II, it moves forward to larger studies.^[3]

Phase III trials compare new treatments directly against current standard therapies in large groups of patients. These are often randomised studies where some people receive the new treatment while others receive the standard approach. This comparison helps determine whether the new treatment is better than, equal to, or worse than existing options. Successful phase III trials often lead to regulatory approval of new medications.^[3]

Several types of innovative therapies are currently being explored in clinical trials for gastroenteropancreatic neuroendocrine tumours. New biological agents that target different molecular pathways involved in tumour growth are under investigation. These include drugs that interfere with other growth factor receptors or that block additional steps in the cell signalling pathways that cancer cells use to survive and multiply. Some studies are testing whether combining multiple targeted agents might be more effective than using them alone.^[3]

Immunotherapy represents an exciting area of research, though it is still in relatively early stages for gastroenteropancreatic neuroendocrine tumours. This approach aims to harness the body’s own immune system to recognise and attack cancer cells. Various strategies are being tested, including checkpoint inhibitors that release brakes on immune cells, allowing them to fight cancer more effectively. While immunotherapy has shown remarkable success in some other cancer types, researchers are still determining which patients with neuroendocrine tumours might benefit most from this approach.^[3]

New chemotherapy combinations and schedules are also being studied to find more effective ways to control rapidly growing tumours while minimising side effects. Some trials explore whether giving chemotherapy in different sequences or combinations with targeted agents might improve outcomes. The combination of capecitabine and temozolomide, for instance, emerged from clinical research and has now become a standard option for many patients with pancreatic neuroendocrine tumours.^[11]

Advances in peptide receptor radionuclide therapy continue through clinical trials testing new radioactive compounds, different dosing schedules, or combinations with other treatments. Researchers are investigating whether this approach might work even better when combined with other therapies, or whether it could be used earlier in the treatment course rather than waiting until other options have been exhausted.^[11]

Clinical trials for gastroenteropancreatic neuroendocrine tumours are conducted at major medical centres across Europe, the United States, and other regions worldwide. Eligibility criteria vary depending on the specific trial but typically consider factors such as the type and location of the tumour, disease stage, previous treatments received, and overall health status. People interested in clinical trials should discuss options with their oncologist, who can help identify suitable studies and explain the potential benefits and risks of participation.^[3]

Most common treatment methods

• Surgery
  • Removal of localised tumours offers the best chance for long-term control when the disease is confined to one area
  • Type of surgery depends on tumour location, such as bowel resection for intestinal tumours or pancreatic surgery for pancreatic disease
  • Even when complete removal is not possible, debulking surgery may help reduce symptoms
• Somatostatin analogues
  • Octreotide and lanreotide bind to receptors on tumour cells to control hormone-related symptoms
  • May also slow tumour growth in some cases
  • Given as injections every few weeks with generally manageable side effects
• Targeted biological agents
  • Everolimus blocks the mTOR pathway that cancer cells use to grow
  • Sunitinib interferes with blood vessel formation that tumours need to grow
  • Both taken as daily pills for ongoing disease control
• Chemotherapy
  • Capecitabine and temozolomide combination shows promise for pancreatic neuroendocrine tumours
  • Other regimens include streptozocin with fluorouracil or doxorubicin
  • Particularly useful for rapidly growing or poorly differentiated tumours
• Peptide receptor radionuclide therapy
  • Lutetium-177 DOTATATE delivers targeted radiation directly to tumour cells
  • Effective for tumours showing high uptake on somatostatin receptor imaging
  • Given as infusions over several months
• Interventional radiology procedures
  • Hepatic artery embolisation blocks blood vessels feeding liver tumours
  • Radiofrequency ablation uses heat to destroy tumour tissue
  • Minimally invasive techniques that can be repeated as needed
• Clinical trial therapies
  • New biological agents targeting different molecular pathways
  • Immunotherapy approaches to activate the immune system against cancer
  • Novel chemotherapy combinations and peptide receptor radionuclide therapy advances