Cancer Types
Common cancer types: symptoms, diagnostic methods and current treatment options.
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Neuroendocrine Tumours (NET): Symptoms, Diagnosis and Treatment
Sources reviewed by: Assoc. Prof. Dr. Ali OğulLast updated: October 2026
Neuroendocrine tumours (NET): symptoms, Ki-67 grade, Ga-68 DOTATATE PET, somatostatin analogues, PRRT and targeted therapies. Mersin.
Key information
| Definition | Tumours arising from hormone-producing cells (NET/NEC) |
|---|---|
| Main risks | Usually no clear cause; hereditary syndromes such as MEN1 |
| Common symptoms | Often no symptoms; flushing, diarrhoea, abdominal pain |
| Diagnosis | Pathology and Ki-67, CT/MRI, Ga-68 DOTATATE PET-CT |
| Treatment | Surgery, somatostatin analogues, PRRT, targeted therapy, chemotherapy |
What are neuroendocrine tumours?
Neuroendocrine tumours develop from hormone-producing cells found in many parts of the body; they occur most often in the digestive system (small intestine, pancreas, stomach, rectum) and the lung. Their behaviour ranges widely, from very slow-growing well-differentiated tumours to rapidly progressing neuroendocrine carcinomas. Treatment is therefore planned individually according to the location and grade of the tumour and whether it carries somatostatin receptors [1][2].
Risk factors
In most neuroendocrine tumours no clear cause is found. Hereditary syndromes such as MEN1, von Hippel-Lindau and neurofibromatosis type 1 are risk factors [2][3].
What are the symptoms?
Many tumours cause no symptoms and are found during tests done for other reasons. Hormone-producing tumours may cause carcinoid syndrome (flushing, diarrhoea, wheezing), low blood sugar (insulinoma) or persistent ulcers (gastrinoma). Abdominal pain, bowel obstruction and weight loss may also occur [1][3].
Most of these complaints can also be caused by other conditions; complaints that persist or get worse need to be assessed by a doctor.
How is it diagnosed?
In pathology, the grade of the tumour (G1–G3) is determined by the Ki-67 index and mitotic count, and well-differentiated tumours (NET) are distinguished from neuroendocrine carcinomas (NEC). Imaging includes CT or MRI as well as somatostatin receptor imaging (Ga-68 DOTATATE PET-CT), and FDG PET-CT for high-grade tumours. Biochemical tests such as chromogranin A and urinary 5-HIAA are done when needed [1][4].
Staging
Staging uses site-specific AJCC/UICC TNM systems. For prognosis and treatment, tumour grade and growth rate are as important as stage [1][4].
Treatment options
- Surgery: Surgery with curative intent is the main treatment for localised tumours; surgery to reduce tumour burden may also be considered in selected metastatic patients.
- Somatostatin analogues: Octreotide or lanreotide both control hormonal symptoms and can slow growth in well-differentiated tumours.
- Peptide receptor radionuclide therapy (PRRT): In progressive somatostatin receptor-positive tumours, Lu-177 DOTATATE is an option delivered by nuclear medicine.
- Targeted and other treatments: Everolimus, sunitinib (pancreatic NET), capecitabine + temozolomide chemotherapy and local treatments for liver metastases may be used.
- Neuroendocrine carcinoma (NEC): Because it progresses rapidly, platinum + etoposide-based chemotherapy is given [4][5].
Treatment is planned individually, taking into account the stage, tumour characteristics, general condition and the patient’s preferences. Not every option listed here is suitable for every patient.
Recent developments
Use of PRRT at earlier lines in well-differentiated, somatostatin receptor-positive tumours and new drugs such as cabozantinib are developments that have entered guidelines in recent years [4][5].
Support and follow-up during treatment
During treatment, not only the anti-cancer drugs but also the patient’s general condition is monitored. Nausea, fatigue, loss of appetite, pain, infection risk and changes in mood are asked about at every visit; when needed, preventive medication, nutritional support, physiotherapy and psychosocial support are planned. In situations such as fever, shortness of breath, uncontrollable diarrhoea or vomiting, or new severe pain, it is advisable to contact the treatment team without waiting for the scheduled visit. Herbal products and supplements can interact with some cancer drugs, so the treatment team should be consulted before using them.
Follow-up intervals depend on the tumour grade; for low-grade tumours, regular imaging over many years is recommended.
Frequently asked questions
‘Carcinoid’ is an older term used for well-differentiated neuroendocrine tumours; today the term ‘neuroendocrine tumour (NET)’ is mostly used.
Ki-67 shows how fast the tumour is growing and is used in grading; it affects the choice of treatment and the frequency of follow-up.
It shows tumours that carry somatostatin receptors and their spread; it is also used to determine suitability for somatostatin analogues and PRRT.
No. Most well-differentiated tumours grow slowly; neuroendocrine carcinomas progress faster and require different treatment.
Call +90 530 250 54 85 or write to the same number via WhatsApp. The outpatient clinic is open Monday to Friday, 08:00–16:00.
At the medical oncology outpatient clinic of Mersin University Faculty of Medicine Oncology Hospital, Çiftlikköy Campus, 33110 Yenişehir/Mersin, Türkiye. The assessment is done in person.
When needed, yes. The multidisciplinary tumour board meets every Friday from 09:00 to 13:00, and the sequence of surgery, radiotherapy and drug treatment is planned jointly.
Yes. A second opinion is a common way to clarify a treatment plan. Bring your pathology, imaging and discharge reports to the clinic for the assessment.
Pathology report, imaging reports and, if possible, the image CDs, discharge summary, recent blood tests and a list of the medicines you take. Translated copies are helpful if your documents are not in Turkish or English.
Medical oncology consultation for a neuroendocrine tumour in Mersin
If you have been diagnosed with a neuroendocrine tumour, or your diagnostic work-up is ongoing, you can apply for a medical oncology consultation with Assoc. Prof. Dr. Ali Oğul at Mersin University Faculty of Medicine Oncology Hospital (Çiftlikköy Campus, 33110 Yenişehir/Mersin, Türkiye). Medical oncology covers the planning of drug treatments such as chemotherapy, targeted therapy, immunotherapy and hormone therapy, the monitoring of side effects and follow-up after treatment. The hospital has a day treatment unit where drug treatments are given.
Treatment decisions are made by a team. When needed, patient files are discussed at the multidisciplinary tumour board, which meets every Friday from 09:00 to 13:00 with specialists from the relevant departments.
For appointments, call +90 530 250 54 85 or send a WhatsApp message to the same number with your name, diagnosis and reason for the request; you can also send your reports. The outpatient clinic is open Monday to Friday, 08:00–16:00. No diagnosis or treatment recommendation is given via WhatsApp; the assessment takes place in person at the clinic. Consultations are held in Turkish.
Appointment
Evaluation and second opinion
If you have been diagnosed with a neuroendocrine tumour or would like a second opinion on your current treatment plan, you can contact Assoc. Prof. Dr. Ali Oğul with your pathology report and imaging results.
This content is for information only; please consult your physician for diagnosis and treatment.
References
- ESMO Clinical Practice Guidelines – Gastroenteropancreatic neuroendocrine neoplasms. Accessed: October 2026. https://www.esmo.org/guidelines/esmo-clinical-practice-guidelines-endocrine-and-neuroendocrine-cancers
- ENETS Guidance Papers. Accessed: October 2026. https://www.enets.org/guidelines.html
- NCI – Neuroendocrine Tumors. Accessed: October 2026. https://www.cancer.gov/types/gi-neuroendocrine-tumors
- NCCN Guidelines – Neuroendocrine and Adrenal Tumors. Accessed: October 2026. https://www.nccn.org/guidelines/category_1
- WHO Classification of Tumours – Digestive System. Accessed: October 2026. https://tumourclassification.iarc.who.int/
Links open external sources. The references were accessible as of October 2026.