Neuroendocrine tumors (NETs) arise from cells that can produce or release hormones. They can develop in the digestive tract, pancreas, lungs, and other organs, and their behaviour varies widely. Treatment depends on where the tumor started, what it looks like under the microscope, how quickly it is growing, whether it has spread, and whether it releases hormones or expresses somatostatin receptors. Options include endoscopic removal, surgery, active surveillance, medicines, and targeted radiation delivered through the bloodstream.
By Dr Raman Narang, Consultant Medical & Hemato-Oncologist, New Delhi
A small rectal NET found during a colonoscopy, a pancreatic NET that has spread to the liver, and a poorly differentiated neuroendocrine carcinoma can all appear under the broad heading of neuroendocrine neoplasms. Each can require a very different plan. If you are seeking neuroendocrine tumor treatment in Delhi, the first step is to establish the exact diagnosis and identify which findings will change the treatment decision.
1. What are neuroendocrine tumors, and what symptoms can they cause?
Neuroendocrine cells receive signals and can release hormones or other substances. Tumors that arise from these cells can occur in the pancreas, small intestine, stomach, appendix, colon, rectum, or lungs. The treatment pathways on this page focus mainly on digestive and pancreatic neuroendocrine neoplasms. Lung neuroendocrine tumors use a separate classification and treatment pathway. [1, 2]
A functioning NET releases enough hormone or another biologically active substance to cause a recognisable set of symptoms. A non-functioning NET can still cause symptoms through its size or location. Some are found during a scan or endoscopy performed for another reason. [1, 2]
| Clinical situation | Possible symptoms |
|---|---|
| Tumor affecting the digestive tract | Persistent abdominal pain, bloating, a change in bowel habits, or bleeding, depending on the site |
| Carcinoid syndrome | Episodes of facial flushing and watery diarrhoea, sometimes with wheezing |
| Insulin-producing pancreatic NET | Repeated low blood sugar, which can cause sweating, trembling, confusion, or fainting |
| Gastrin-producing NET | Recurrent ulcers, acid-related symptoms, or diarrhoea |
| Incidentally detected NET | No symptoms at the time of diagnosis |
These symptoms have many possible causes. When a hormone-related syndrome is suspected, the pattern of symptoms helps determine which tests are worth doing. [1, 2]
2. How are neuroendocrine tumors classified?
The words site, differentiation, grade, stage, and functioning status each describe a different part of the diagnosis. Together they explain why two people with a neuroendocrine tumor may be offered very different treatments. [2, 3]
| Term on the report | What it means for treatment |
|---|---|
| Primary site | Where the tumor began. A small bowel NET, pancreatic NET, and rectal NET have different staging and treatment pathways. |
| Differentiation | How closely the tumor cells resemble normal neuroendocrine cells. The main distinction is between a well-differentiated NET and a poorly differentiated neuroendocrine carcinoma (NEC). |
| Grade | How actively the cells are dividing. For well-differentiated digestive and pancreatic NETs, pathologists use the Ki-67 index and mitotic count to assign grade 1, 2, or 3. |
| Stage | How far the tumor has spread, including whether it involves nearby lymph nodes or distant organs such as the liver. |
| Functioning status | Whether hormone release is causing a clinical syndrome that needs treatment alongside the tumor. |
For well-differentiated digestive and pancreatic NETs, the usual Ki-67 ranges are below 3% for grade 1, 3–20% for grade 2, and above 20% for grade 3. Pathologists also assess the mitotic count and use the higher grade when the two measures disagree. A well-differentiated grade 3 NET and a poorly differentiated NEC can both have a high Ki-67, yet they often require different treatments. The appearance of the cells is essential to telling them apart. Lung tumors are classified using different criteria. [2, 3]
3. How are neuroendocrine tumors diagnosed and staged?
Diagnosis usually starts with a biopsy or removal of the lesion, followed by pathology review. The team then chooses scans and laboratory tests based on the suspected site and subtype. Each test answers a specific question. [1–3]
- Pathology and immunohistochemistry. The pathologist examines the appearance of the cells and uses markers such as synaptophysin and chromogranin to help confirm neuroendocrine differentiation. In digestive and pancreatic NETs, the report should also address the Ki-67 index and grade.
- Contrast CT or MRI. These scans show where the tumor is, what structures it involves, and whether it has spread. A liver MRI can help define the extent of liver involvement when that information would affect the plan.
- Somatostatin receptor PET/CT. A scan such as Gallium-68 DOTATATE PET/CT can show where a well-differentiated NET is and whether it expresses somatostatin receptors. That information can help assess eligibility for peptide receptor radionuclide therapy (PRRT).
- FDG PET/CT. This can be useful in selected higher-grade or faster-growing disease, particularly when the findings could change the treatment strategy.
- Endoscopy or endoscopic ultrasound. These can help locate, sample, or sometimes remove a lesion, depending on whether it is in the stomach, pancreas, rectum, or another accessible site.
- Blood or urine tests. A 5-HIAA test may be appropriate when carcinoid syndrome is suspected or in selected small bowel NETs. Other hormone tests are chosen according to the symptoms. A raised blood chromogranin A alone cannot establish the diagnosis. [1–3]
4. How are localised and locally advanced neuroendocrine tumors treated?
When a well-differentiated NET is confined to its starting organ or nearby tissues, treatment may aim to remove it completely. The operation or procedure depends on the organ, tumor size, grade, depth, and lymph node involvement. [1, 2]
- Endoscopic removal may be suitable for selected small, low-risk rectal or gastric NETs. After removal, the pathology report helps determine whether further assessment or treatment is needed. For a rectal NET found after a routine polyp removal, the depth of invasion, grade, and margins are particularly relevant.
- Surgery is often considered for a removable small bowel or pancreatic NET. For a small bowel NET, the surgeon assesses the bowel and nearby lymph nodes. For a pancreatic NET, the proposed operation depends in part on where the tumor sits and its relationship to the pancreatic duct and nearby structures.
- Active surveillance may be appropriate for selected small, non-functioning pancreatic NETs with low-risk features. This involves a planned schedule of follow-up and a clear discussion about what change would prompt treatment.
- Locally advanced disease may require review by a specialist surgeon, medical oncologist, radiologist, and nuclear medicine physician. If complete removal is difficult, the team considers what systemic or local treatment could achieve. A poorly differentiated NEC often needs systemic chemotherapy as part of the plan, even when imaging shows no distant spread. [1–3]
5. How are metastatic neuroendocrine tumors treated?
For a metastatic well-differentiated NET, the team considers how quickly the disease is progressing, whether it is causing symptoms, and whether treatment needs to shrink the tumor or mainly slow its growth. Liver involvement, somatostatin receptor expression, and previous treatments all influence the sequence. [4, 5]
| Treatment | When it may be considered |
|---|---|
| Somatostatin analogues | Octreotide or lanreotide can help control hormone-related symptoms and slow growth in many well-differentiated NETs. |
| PRRT with lutetium-177 DOTATATE | A receptor-targeted treatment for selected patients whose tumors show sufficient uptake on somatostatin receptor imaging. The nuclear medicine team also assesses kidney function and bone marrow reserve. |
| Targeted medicines | Everolimus has a role in selected advanced NETs. Sunitinib is an option for selected pancreatic NETs. The choice depends on the primary site, prior treatment, and expected side effects. |
| Chemotherapy | Capecitabine plus temozolomide, often called CAPTEM, is an option for selected advanced pancreatic NETs, particularly when tumor shrinkage is an important goal. |
| Liver-directed treatment | Ablation, embolisation, or surgery may be considered in selected patients whose disease is predominantly in the liver. |
| Active surveillance | Some patients with low-volume, slowly growing disease and minimal or no symptoms can be monitored before starting systemic treatment. |
Poorly differentiated metastatic digestive NEC usually needs a different approach. Platinum-based chemotherapy, often combined with etoposide, is a common first treatment. For a well-differentiated grade 3 NET, options can differ substantially and depend on the primary site, receptor imaging, pace of disease, and whether rapid shrinkage is needed. [3, 4]
What I look for clinically before recommending treatment
I start with the pathology report and the original scans. If the report says “high-grade neuroendocrine neoplasm,” I want to clarify whether it is a well-differentiated grade 3 NET or a poorly differentiated NEC. If a well-differentiated NET has spread, I look at how much it has changed between scans and whether hormone-related symptoms need attention now. Those details help decide whether the next step is monitoring, a treatment that slows growth, or a treatment chosen because shrinkage is important.
How the next step is decided
| If the reports show… | The next discussion is about… |
|---|---|
| A small NET removed during colonoscopy | Grade, depth, margins, and whether further treatment or surveillance is needed |
| A localised pancreatic or small bowel NET | Whether surgery is appropriate and what it would involve |
| An unclear high-grade diagnosis | Expert pathology review to distinguish grade 3 NET from NEC |
| A growing metastatic NET with strong receptor uptake | Whether PRRT fits the treatment sequence |
| Flushing, diarrhoea, or recurrent low blood sugar | Whether a hormone-related syndrome needs specific testing and treatment |
What to bring to a neuroendocrine tumor consultation in Delhi
- Biopsy or surgical pathology report, including the Ki-67 percentage, grade, and differentiation if reported.
- Pathology slides or tissue block details, especially if the diagnosis or grade is uncertain.
- CT, MRI, DOTATATE PET/CT, or FDG PET/CT reports and original images.
- Endoscopy, colonoscopy, or endoscopic ultrasound reports, if performed.
- Relevant hormone results and a brief record of symptoms such as flushing, diarrhoea, or low blood sugar.
- Dates and details of previous surgery, injections, PRRT, chemotherapy, or other cancer treatments.
Frequently asked questions
Is grade 3 the same as stage IV?
Grade describes how actively the tumor cells are dividing. Stage describes where the tumor is and how far it has spread. A grade 3 tumor can be localised, and a grade 1 NET can have distant spread. [2, 3]
Does every neuroendocrine tumor need chemotherapy?
Treatment depends on the subtype. Surgery, surveillance, somatostatin analogues, or PRRT may be appropriate for selected well-differentiated NETs. Chemotherapy has an important role in poorly differentiated NEC and in selected well-differentiated NETs. [3, 4]
Does a positive DOTATATE scan mean I should have PRRT next?
Receptor uptake is one requirement. The decision also depends on the degree and distribution of uptake, how quickly the disease is progressing, prior treatment, kidney function, and bone marrow reserve. [4, 5]
Can a neuroendocrine tumor be cured?
Some localised NETs can be treated with the aim of cure by complete removal. When disease has spread, treatment often focuses on controlling the tumor and any hormone-related symptoms. The expected course varies by subtype, grade, and extent of disease. [1–4]
At your consultation, ask for the diagnosis in one sentence that includes the primary site, differentiation, grade, and stage. Then ask which of those findings is driving the proposed treatment and how the team will judge whether it is working.
This page is for general education. Individual treatment decisions require review of your pathology, imaging, symptoms, and overall health by your treating team.
Clinical references
- National Cancer Institute. Pancreatic Neuroendocrine Tumor Diagnosis and Staging.
- SEOM–GETNE. Clinical Guidelines for the Diagnosis and Treatment of Gastroenteropancreatic and Bronchial Neuroendocrine Neoplasms.
- NANETS. Expert Consensus Practice Recommendations for the Management of High-Grade Gastroenteropancreatic and Gynecologic Neuroendocrine Neoplasms.
- ASCO. Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors.
- US Department of Veterans Affairs. Oncology Clinical Pathways: Gastrointestinal Neuroendocrine Tumors.