|
Getting your Trinity Audio player ready...
|
Neuroendocrine cancers of the colon are rare cancers that develop from neuroendocrine cells in the large bowel. They include neuroendocrine tumours (NETs), which are usually slower growing, and neuroendocrine carcinomas (NECs), which tend to grow more quickly.
Neuroendocrine cancers of the colon may not cause symptoms in their early stages. Most do not produce excess hormones, and symptoms that do occur may be similar to those of other bowel conditions, such as changes in bowel habits, abdominal discomfort or blood in the stool.
This page explains more about neuroendocrine cancers of the colon, including possible causes and symptoms, diagnosis, treatment and follow-up care. It also includes information about living with your diagnosis and where to find further information and support.
Use the links in the box to find the information that is most relevant to you.
What is neuroendocrine cancer of the colon?
Neuroendocrine cancer is a type of cancer that begins in the neuroendocrine cells, which are found throughout the body. These cells have the ability to release hormones that can regulate many body functions. When they become cancerous, their growth rate and normal function is disrupted.
There are two main types:
- Neuroendocrine Tumours (NETs) – usually slower growing
- Neuroendocrine Carcinomas (NECs) – less common and faster growing
Treatment and outlook depend on factors including tumour type, grade, stage, differentiation and whether the cancer has spread.
Watch our video: Spotlight on Small and Large Bowel Neuroendocrine Cancers
About the large bowel
The colon (large bowel) is the long, hollow tube-like organ that connects the small intestine at one end to the anus at the other.
It is approximately 6 feet (1.8 metres) long and around 3 inches (8 cm) in diameter. The large intestine consists of the caecum, colon, rectum and anus.
The large bowel receives liquid food waste after the small bowel has completed most digestion and nutrient absorption. By the time food reaches the colon, up to 90% of the water and most nutrients have already been absorbed.
The main functions of the large bowel are to:
- Absorb remaining water, salts and electrolytes
- Process waste material into stool (faeces)
- Store stool before it leaves the body
- Support healthy gut bacteria
- Assist production and absorption of vitamins including vitamin K and several B vitamins
Watch our video: The Digestive System
The colon is composed of five sections:
- Caecum: the first part of the colon. Digested food waste enters from the small bowel through the ileocaecal valve. The appendix is attached to the caecum.
- Ascending colon: absorbs water and electrolytes while moving waste upwards.
- Transverse colon: the longest section of the colon. It carries waste across the abdomen from right to left.
- Descending colon: continues stool formation and storage.
- Sigmoid colon: the final section of the colon before the rectum. It helps move stool into the rectum for elimination.
Friendly gut bacteria
The colon contains trillions of bacteria which:
- Help protect against harmful organisms
- Break down remaining carbohydrates through fermentation
- Produce vitamins including vitamin K, biotin and other B vitamins
- Contribute to overall gut health
Formation and transport of faeces
Approximately 500 ml of food residue enters the colon daily. Around 150 ml eventually becomes faeces. Faeces contain:
- Bacteria
- Fibre
- Water
- Undigested food material
- Shed intestinal cells
- Small amounts of fat and protein
Transit through the colon is slow. Most material takes around three days to pass through the large bowel, although complete elimination of all remnants from a meal can take up to one week. Normal bowel habits vary significantly, ranging from three bowel motions each day to three per week.
The Bristol Stool Chart
The Bristol Stool Chart can be used to describe stool type and appearance. Alongside information about frequency, colour and symptoms, it can help healthcare professionals identify constipation, diarrhoea and other bowel conditions.
How does neuroendocrine cancer of the large bowel develop?
Neuroendocrine cancers develop when neuroendocrine cells acquire genetic changes that disrupt their normal life cycle. Instead of growing, dividing and dying in a controlled way, the cells continue to grow abnormally and form a tumour.
Neuroendocrine cancers of the large bowel may be:
- Well-differentiated neuroendocrine tumours (NETs)
- Poorly differentiated neuroendocrine carcinomas (NECs)
Primary neuroendocrine cancers of the colon are rare.
We do not yet fully understand exactly what causes neuroendocrine cancer. Most occur sporadically and are not inherited.
However, for the large bowel, potential risk factors may be similar to those associated with bowel cancer – for example:
- Increasing age
- Obesity
- Diabetes
- Smoking
- Excess alcohol consumption
- Family history of cancer
Certain inherited conditions may also increase risk, including:
- Lynch Syndrome (HNPCC)
- Familial Adenomatous Polyposis (FAP)
If you have a family history of bowel cancer, neuroendocrine cancer or a known hereditary cancer syndrome, it is important to discuss this with your specialist team.
Signs and symptoms
Many people experience no symptoms during the early stages of disease.
1. Symptoms caused by the tumour itself
Possible symptoms may be similar to those seen in bowel cancer – and may include:
- A persistent change in bowel habit
- Diarrhoea and/or constipation
- A change in stool consistency
- Rectal bleeding
- Blood in the stool
- Black or tar-like stools
- Persistent abdominal discomfort
- Bloating
- Excess wind (gas)
- Abdominal cramps or pain
- A feeling that the bowel does not empty completely
- Fatigue or weakness
- Unexplained weight loss
2. Symptoms caused by hormone syndromes
Hormone-producing tumours may cause specific syndromes that can sometimes provide clues about where the primary tumour originated. Most neuroendocrine cancers of the colon are non-functioning and do not produce excess hormones. Rarely, a hormone-producing neuroendocrine tumour may lead to symptoms such as carcinoid syndrome.
Carcinoid syndrome is usually associated with metastatic well-differentiated NETs. Symptoms may include:
- Flushing
- Diarrhoea
- Wheezing
- Rapid heartbeat
- Sweating
- Abdominal discomfort
Carcinoid crisis (rare) may occur in those who have carcinoid syndrome
Carcinoid crisis can happen during anaesthesia or tumour manipulation (biopsy, surgery or interventional radiology – e.g. embolisation or ablation treatments) or be triggered by mental/physical stress.
Symptoms may be similar to carcinoid syndrome but are much more severe. These include severe flushing – often accompanied by palpitations or a fast, irregular heart rate, low blood pressure, confusion and breathing difficulty – and can be life-threatening.
Specialist teams plan care to reduce this risk.
If you are at risk of carcinoid crisis, carry a Carcinoid Crisis Card so healthcare professionals know how to manage your care in an emergency. You can order one from us for free.
3. Rare symptoms (paraneoplastic syndromes)
Very rarely, cancer can trigger symptoms caused by the body’s immune response to cancer. These are uncommon but can sometimes cause serious health problems.
Watch our video: Paraneoplastic Syndromes – Explained
4. Symptoms related to treatment
Treatments can cause side effects, but not everyone experiences them.
Your team will talk through possible side effects and how they can be managed.
Tests and scans
Investigations are guided by symptoms, tumour behaviour and primary site. A comprehensive assessment usually includes:
- Clinical examination
- Blood and urine tests
- Cross-sectional imaging
- Functional imaging
- Endoscopy
- Histopathology
Your specialist team may recommend a combination of the following investigations.
Blood and urine tests
- Full blood count (FBC)
- Liver function tests
- Kidney function tests
- Vitamin B12
- Iron studies, ferritin, folate
- Chromogranin A
- Urinary or serum 5HIAA (serotonin)
- CEA and/or Beta-HCG
- NT-ProBNP may be taken if you have a history of heart disease or carcinoid syndrome (NET only)
- Vitamin, mineral and trace element check
Other blood tests may be taken, but this will be decided on a case-by-case basis, guided by your symptoms and clinical expertise.
Scans and procedures
Structural imaging:
- CT chest, abdomen and pelvis
- MRI abdomen and pelvis
Functional imaging:
- Gallium-68 DOTATATE PET/CT
- Octreotide SPECT scan
- FDG-PET scan
Additional imaging:
- Bone scintigraphy (if bone disease is suspected)
- Echocardiogram where appropriate
Endoscopy: a colonoscopy allows direct examination of the large bowel and enables tissue samples (biopsies) to be taken. This procedure can play an important role in identifying the precise location of lesions before surgery. Endoscopic marking techniques may include:
- India ink tattooing
- Metallic clip placement
These techniques can help surgeons identify subtle lesions during surgery.
Watch our video: Your Guide to Scans
Histopathology
This means looking at cells and tissues under a microscope to understand disease. It helps confirm whether cancer is present, where it started, what type of cells are involved, and how quickly the cells are growing.
Your doctor will explain which biopsy is best for you and why. You will also have time to ask questions and give consent before the procedure
A combination of these investigations will help confirm your diagnosis and guide treatment decision-making.
Cancer gene changes and targeted treatments
Some neuroendocrine cancers (particularly NECs) may contain specific genetic alterations that can be targeted with treatment.
Examples include:
- PD-L1 expression
- DLL3 expression
- Other molecular alterations
Genomic testing may help identify targeted treatment options or eligibility for clinical trials.
Treatment options
The aim of treatment is to provide the best possible outcomes, symptom control and quality of life.
Treatment recommendations depend on:
- NET or NEC diagnosis
- Tumour grade
- Tumour size
- Location within the bowel
- Whether disease has spread
- Your overall health and preferences
All patients should be discussed within a specialist neuroendocrine multidisciplinary team (MDT).
1. Monitoring (surveillance)
Sometimes referred to as ‘watch and wait’, monitoring may be used following treatment to check how well the treatment worked, or to monitor stable disease. When active treatment is not currently needed, monitoring is required.
This typically involves a clinical review, blood tests and further scans or investigations.
2. Surgery
Surgery may be appropriate when:
- Disease can be safely removed
- Symptoms can be improved
The aim would be to completely remove the tumour and nearby lymph nodes.
However in NETs or where surgery is required to treat an obstruction, complete removal of all disease may not be possible. But debulking or removing an obstruction can still provide benefit.
Depending on the site of tumour, once removed, the healthy bowel ends are joined together. This join is called an anastomosis. If the bowel cannot be rejoined, then a temporary or permanent stoma may be required: this possibility will be discussed with you before surgery.
What is a stoma?
A stoma is created by bringing part of the bowel onto the surface of the abdomen. Waste passes into an external pouch (stoma bag):
- A large bowel stoma is called a colostomy
- A small bowel stoma is called an ileostomy
Types of large bowel surgery include:
- Right hemicolectomy: removes the ascending colon and sometimes the ileocaecal valve.
- Extended right hemicolectomy: removes the ascending and transverse colon.
- Left hemicolectomy: removes the descending colon.
- Hartmann’s procedure: removes the sigmoid colon and upper rectum. May require a temporary stoma.
- Subtotal colectomy: removes most of the colon but leaves the rectum.
- Proctocolectomy: removes the colon and rectum.
- Pan-proctocolectomy: removes the colon, rectum and anus. A permanent stoma is required.
If a cancer is very small or confined within a polyp, local resection through surgery or colonoscopy may be suitable. Surgery may also be performed to relieve symptoms such as bowel obstruction.
Endoscopic treatment is mainly used for small, early-stage NETs that are found in the rectum. Neuroendocrine tumours found in other parts of the bowel are often more aggressive and usually need an operation to remove part of the bowel.
3. Other treatments (non-surgical)
NET treatments options
- Somatostatin analogues (SSAs): used to control hormone-related symptoms and/or tumour growth.
- Targeted medical therapy (e.g. the mTOR inhibitor everolimus): these are targeted treatments that block a protein that cancer cells use to grow and divide, helping to slow or stop tumour growth.
- Chemotherapy: rarely used as a first treatment for low grade (G1-2) NETs but may be considered in G2-3 or if other treatments are not suitable or have stopped working. It may be given as tablets or through a drip into a vein. For example CapTem (capecitabine + temozolomide) tablets or, rarely, Streptozocin/5FU via a drip.
- Radiotherapy: external beam radiation therapy (EBRT) may be used, following surgery or to treat symptomatic bone metastases.
- Radioligand therapy (RLT, also known as PRRT or lutetium‑177): mainly used for metastatic or progressing disease. It is a targeted internal radiation treatment. It delivers radiation directly to cancer cells, usually given in four sessions spaced 8–12 weeks apart.
- Symptom control and supportive care: includes any treatment or support that helps you feel better, even if it is not directly treating the cancer. This may include medicines, dietary advice and/or psychological support. Techniques such as mindfulness or relaxation may help with pain, fatigue, stress or anxiety.
- Clinical trial therapy: clinical trials are used to find out if new treatments and techniques are safer and more effective than the ones that already exist, or for discovering if existing treatments can be used in different, more effective, ways or combinations.
NEC treatment options
- Chemotherapy: is considered first line treatment for neuroendocrine carcinomas in inoperable disease. It may also be considered if surgery is not possible or after surgery – if it was incomplete or doctors think there is a high risk of recurrence. The main treatment is usually platinum-based chemotherapy, sometimes combined with etoposide (or irinotecan in certain cases). If the cancer comes back or grows, further treatment options may include reusing the first treatment or trying other forms of chemotherapy.
- Radiotherapy: external beam radiation therapy (EBRT) may be used to treat symptomatic bone metastases.
- Immunotherapy: clinical trials are looking promising in treating NECs, but it has yet to become a standard of care. Research is ongoing. Immunotherapy may be considered in NEC if available and accessible. Types of treatment may include immune checkpoint inhibitors, which help your immune system recognise and attack cancer by removing the ‘brakes’ that normally hold it back, and DLL3 Inhibitors, which target a protein called DLL3, frequently over-expressed in high-grade neuroendocrine cancers.
- Symptom control and supportive care: includes any treatment or support that helps you feel better, even if it is not directly treating the cancer. This may include medicines, dietary advice and/or psychological support. Techniques such as mindfulness or relaxation may help with pain, fatigue, stress or anxiety.
- Clinical trial therapy: clinical trials are used to find out if new treatments and techniques are safer and more effective than the ones that already exist, or for discovering if existing treatments can be used in different, more effective, ways or combinations.
Diagnosis and living with neuroendocrine cancer of the large bowel
A diagnosis of neuroendocrine cancer can bring questions, uncertainty and a range of emotions. Information and support are available to help you understand your diagnosis and navigate what happens next.
Just diagnosed with neuroendocrine cancer? Access information and support to help you navigate the early days after diagnosis.
Follow-up care
Follow-up is an important part of your ongoing care. It helps your healthcare team check how you are doing, spot any changes early, and support your physical and emotional wellbeing.
While expert guidelines offer a general plan for follow-up, your care will always be tailored to you and your specific type of neuroendocrine cancer.
At each appointment, your team will ask how you are feeling, review your symptoms and medications, and arrange blood tests if needed.
You may also be offered a holistic needs assessment (HNA). This is an opportunity to talk with your specialist nurse or doctor about any physical, emotional, practical, or social needs, so the right support can be put in place.
According to expert guidelines
After treatment for a neuroendocrine tumour of the colon or rectum, some people need very little follow-up, while others require regular scans and appointments for several years. The amount of follow-up depends on the type of tumour, its size, whether it was completely removed, and the risk of it returning. Your specialist team will create a follow-up plan that is right for you.
Your case should be discussed by a specialist multidisciplinary team (MDT) to ensure the most appropriate follow-up plan.
If you have a well-differentiated NET:
- Small tumours (1 cm or less) that have been completely removed: if there are no high-risk features, you may not need regular follow-up tests, as the risk of the tumour returning or spreading is low.
- Larger tumours (greater than 1 cm), tumours with higher risk features or tumours that were incompletely removed: you will usually need ongoing monitoring. This may include CT or MRI scans of the chest, abdomen and pelvis; blood tests, sometimes including chromogranin A (CgA);and regular clinic appointments.
Scans are usually carried out every 6 to 12 months. Follow-up may continue for 5 to 10 years, depending on your individual risk of recurrence.
If you have a poorly differentiated NEC or mixed neuroendocrine–non-neuroendocrine neoplasm (MiNEN), these tumours tend to grow and spread more quickly and require closer monitoring. Follow-up usually includes regular specialist appointments, CT or MRI scans, and monitoring during and after treatment.
Scans are often performed every 3 to 4 months during treatment and in the early period afterwards.
After surgery
If you have had bowel surgery, such as removal of part of the colon or rectum:
- Your surgical results will be reviewed carefully.
- If the tumour was not completely removed or there is concern that lymph nodes were involved, you may need more frequent scans.
- Follow-up imaging may be performed every 3 to 6 months during the first 2 to 3 years to look for any signs of the tumour returning.
Advanced disease
Follow-up should take account of:
- Treatment goals
- Disease behaviour
- Treatment benefit
- Treatment toxicity
- Quality of life
- Your preferences and wishes
How you can be part your care
You are an important member of your healthcare team. You can help by:
- Reporting new symptoms or any changes in current symptoms or overall health promptly
- Attending scheduled appointments
- Asking questions
- Sharing your priorities and concerns
- Understanding your treatment plan
- Letting your team know if appointments are delayed or missed
Support and further information
We have worked with the International Neuroendocrine Cancer Alliance (INCA) to provide information resources in more than 10 different languages: these are available here.
Living with a stoma can take time to get used to, but support is available. Your stoma care nurse, GP and specialist organisations can help with stoma care, supplies, practical issues and emotional support. Do not hesitate to ask for help if you have any concerns or difficulties.
- Colostomy UK: Provides information, emotional support, local groups and practical advice. Free helpline: 0800 328 4257.
- Ileostomy & Internal Pouch Association: Provides information, support groups and peer support for people with an ileostomy or internal pouch.
Other sources of support including benefits/financial, stoma care and general cancer advice:
- Cancer Research UK: Provides comprehensive guides on diagnosis and living with neuroendocrine cancer of the colon, alongside a nurse-staffed helpline and online peer chat spaces.
- Maggie’s Centres: Run drop-in centers across the UK providing free practical, emotional and social support from professional specialists.
- Macmillan Cancer Support: Offers a free support line (0808 808 00 00) for general cancer advice and financial guidance.
Stories from our community
Hear from people connected to neuroendocrine cancer as they share their experiences, perspectives and insights – from living with the condition to caring for, treating and supporting those affected.
Remember
Every person’s experience of neuroendocrine cancer of the large bowel is different – there may be shared similarities, but each journey is unique.
Your healthcare team will support you every step of the way, guiding your treatment, care, and follow-up. We’re here alongside them, offering additional support and information whenever you need it.
The information on this page is based on available clinical expert guidelines and publications. It is for informational purposes only and should not be considered professional medical advice.
