A fistula is an abnormal opening between organs or other structures in the body. Fistulas are more common in the pelvic area.

Fistulas are a rare side effect of cancer treatment. They can also develop as the result of a cancer growing.

Symptoms of a fistula depend on where it is in the body. Common symptoms include:

  • leaking urine through the vagina or back passage
  • passing bowel movements or wind through the vagina
  • unpleasant-smelling vaginal discharge.

You may need a number of tests to find out if you have a fistula. The tests you have will depend on the part of the body affected. They may include:

  • CT scans
  • MRI scans
  • contrast X-rays.

Treatment for a fistula depends on what’s causing it. They can take a long time to heal and some may not heal completely. However, it’s often possible to control symptoms very successfully.

You may feel embarrassed or worried because of your fistula. But you’ll probably be much more aware of it than others. Talking things over can help.

What is a fistula?

A fistula is an abnormal opening or channel that joins two or more structures or spaces within the body. For example, a fistula can develop between two organs of the body, such as the bowel and the bladder, or the bowel and the skin.

A cancer fistula is rare. It develops because of cancer or its treatment. If it is caused by cancer treatment, it‘s often a late side-effect and may take many months or years to develop. Some conditions or treatments that are not related to cancer can also cause a fistula.

Fistulas can occur almost anywhere in the body, although they are more common in the pelvic area. A fistula is usually named after the parts of the body involved.

A fistula can develop between:

  • one of the tubes (ureter) leading from the kidney to the bladder and the vagina (called a uretero-vaginal fistula)
  • a ureter and the bowel (called a uretero-colic fistula)
  • the bladder and the vagina (called a vesico-vaginal fistula)
  • the bowel and the skin, usually the abdominal wall (called an enterocutaneous fistula)
  • the bowel and the vagina (called a recto-vaginal fistula)
  • the bowel and the bladder (called an entero-vesical fistula).

Less commonly, fistulas can develop between:

  • the windpipe (trachea) and the gullet (oesophagus) (called a tracheo-oesophageal fistula)
  • the gullet and the lungs, the main airways to the lungs (bronchus), or the windpipe (called a broncho-oesophageal fistula)
  • the stomach and the bowel (called a gastro-colic fistula).

Causes and risk factors of a cancer fistula

There are some risk factors that can increase the chance of developing a fistula. However most people with cancer, even with these risk factors, will never develop one.

Some of the factors that can increase the chances of a cancer fistula are:

  • The cancer itself - there's more risk of fistula in cancers that are large and grow faster (high grade cancers), and in gynaecological and bowel cancers.
  • Other medical conditions - for example, high blood pressure, anaemia, diabetes, or bowel conditions like colitis, Crohn’s disease or diverticulitis. People who are very overweight or poorly nourished are also at a higher risk.
  • Previous surgery - especially in the pelvic area.
  • Cancer treatment - this includes previous radiotherapy, especially in combination with surgery, and to a lesser extent in combination with chemotherapy.
  • A biopsy - if the biopsy is taken from an area that has previously been irradiated, it can sometimes cause a fistula.
  • Radiation damage to the bowel - if you have a long-term bowel condition because of radiotherapy to the pelvic area (chronic radiation enteritis), you're more likely to develop a fistula of the bowel.

Assessment and diagnosis of a cancer fistula

Sometimes the symptoms of a fistula can be mistaken for the symptoms of another condition. A number of tests and investigations may be done to find out exactly what is causing the symptoms.

It’s important to know whether a fistula has developed because of a cancer that is growing, or as a result of previous treatment. This is because the way the fistula is managed will be different depending on why it has developed.

Your doctor will ask about your symptoms and talk to you about any surgery or treatment you've had in the past. They may also need to do a physical examination of the affected area. As many fistulas can develop in the pelvic area, some people feel embarrassed by this procedure. If you would prefer to be examined by a doctor of the same sex as you, just let your doctor or nurse know.

The kind of tests used will depend on the symptoms you have and the area of the body that is affected. Your doctor or nurse will explain the investigations to you and will answer any questions you have. Some of the tests that can be used are:

Methylene blue test

This is used to help diagnose a fistula involving the vagina and bowel. A tampon is placed into the vagina and then some harmless blue dye (methylene) is placed into the back passage. After about 10-15 minutes the tampon will be removed. Blue staining on the tampon shows that there is a fistula.

CT (computerised tomography) scan

A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of your body. The scan is painless but takes about 10-30 minutes. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan. A CT scan can be used to identify a fistula and show exactly which parts of the body are affected.

MRI (magnetic resonance imaging) scan

This test is similar to a CT scan, but uses magnetism instead of x-rays to build up a detailed picture of an area of your body. During the scan you will be asked to lie very still on the couch inside a long tube for about 30 minutes. It is painless but can be uncomfortable, and some people can feel a bit claustrophobic during the scan. It is noisy, but you will be given ear plugs or headphones.

Contrast x-rays

Sometimes a liquid that shows up on x-rays is used to help show the structures of the body affected by the fistula. The liquid is called a contrast medium. It can be injected into a vein in your arm or inserted into the part of the body that is affected, such as the bladder, the vagina or a fistula opening on the skin. The liquid is completely harmless.

The different types of contrast x-ray are explained below:


To help diagnose a fistula involving the bladder, the contrast medium is inserted into the bladder using a thin, rubber tube (catheter).


This test can help to show whether there is a fistula involving the vagina. A thin, rubber tube (catheter), which has a small balloon on the end, is inserted into the vagina. The balloon is then inflated to block the opening of the vagina before the contrast liquid is injected into the vagina through the catheter. X-rays of the vagina are then taken, and any leakage of the liquid will show the position and size of a fistula.


A very small catheter or blunt needle is inserted into the opening of the fistula on the skin. The contrast liquid is then injected into the fistula and x-rays are taken.

Intravenous urogram (IVU/IVP)

This test, also known as an intravenous pyelogram, can help show a fistula involving the bladder and kidneys. It is done in the hospital x-ray department and takes about an hour.

A dye is injected into a vein, usually in the arm, and flows through the bloodstream to the kidneys. The doctor can watch the passage of the dye on an x-ray screen and see any abnormalities in the kidneys, bladder and the rest of the urinary system.

The dye will probably make you feel hot and flushed for a few minutes, but this feeling gradually disappears. You may feel some discomfort in your abdomen, but this will only be for a short time. You should be able to go home as soon as the test is over.

Barium x-rays

These tests can be done to look for a fistula involving the digestive system. Barium is a substance that shows up on x-rays and can be given as a drink or in an enema. You may need to have an empty bowel before your barium x-ray so that a clear picture can be seen. Your hospital will give you instructions, but it is likely that you will be asked to take a laxative on the day before the test and to drink plenty of fluids.

Depending on which part of the body is being investigated, you'll either be given a drink of liquid containing the barium (a barium meal or swallow) or an enema of a liquid containing the barium (a barium enema). The doctor can watch the passage of the barium through your digestive system on a screen and can see any abnormalities.

Examination under anaesthetic (EUA)

This allows your doctor to carefully examine the areas affected by the fistula while you are under a general anaesthetic. The doctor can do a thorough examination without causing you any discomfort.

Treatment for a cancer fistula

The treatment for a fistula will often depend on its cause. If the fistula has developed because of damage caused by radiotherapy, it may be possible to do an operation to close the opening. If the fistula has formed as a result of a recurrence of the cancer, surgery may not be possible, and treatment to manage the symptoms may be given.

Sometimes a fistula will close without surgery and can be managed with treatment to control symptoms.

You may be seen by a number of different doctors. For example, if you have a fistula affecting your bowel and bladder, your cancer doctor may involve a bowel specialist (gastroenterologist) and a bladder specialist (urologist). You may also see a plastic surgeon.

Fistulas can often take many weeks or months to heal. Not all fistulas are treatable and some may never heal, although it is often possible to control the symptoms very successfully. Your doctor or specialist nurse can discuss treatment options with you further.


Surgery may only be possible if the tissue in the area around the fistula is healthy. Previous radiotherapy treatment to the area or scarring caused by previous surgery can affect healing. In these situations healing may take longer than normal, and in some circumstances the area may not heal at all.

The type of operation will depend on the areas of the body affected, and your team of specialists will discuss with you what the surgery will involve. They will explain and discuss with you how the operation will affect you and whether there are any possible risks.

Plastic surgery

Plastic surgery will either involve a skin graft or a tissue flap. A skin graft involves taking some skin from a different part of the body (called the donor site) and using it to repair the operation site. A tissue flap is a larger operation, and uses tissue and skin. The plastic surgeon will explain your operation to you and answer your questions.


If the fistula involves part of the bowel, it is sometimes necessary to bring the bowel out on to the skin of the abdominal wall (tummy) to make a false opening (stoma). The stoma is called a colostomy if it uses part of the colon, and called an ileostomy if it uses the small bowel. A bag is worn over the stoma to collect bowel motions.

The stoma will either be temporary or permanent. A temporary stoma may be needed to divert the bowel and allow symptoms, such as infection and inflammation, to improve before an operation. It can also allow for the area to heal after surgery.

Your surgeon and specialist nurse will discuss stomas with you if you need to have one.

If the fistula involves the urinary system, a stoma to collect urine (called a urostomy) is sometimes needed. The urostomy, like a stoma involving the bowel, will either be temporary or permanent.

Anti-cancer treatments

If the fistula has developed because of a growing cancer, treatment may be given to reduce the size of the cancer. This may help the fistula close up.

Depending on the type of cancer and the position of the fistula, chemotherapy and sometimes radiotherapy may be used. Your doctor or specialist nurse will explain the treatment and give you information about any possible side effects.

Controlling the symptoms of a cancer fistula

Treatment will be given to help control any symptoms. It’s important that you tell your nurse or doctor how the fistula is affecting you. This is so they can give you advice on the best way to manage your symptoms.

Skin care

The skin can often become sore and red, and may become infected and ulcerated. Barrier creams or films that cover the area can help reduce symptoms. Some creams and films contain local anaesthetic, which helps reduce pain and discomfort.

Your specialist nurse can advise you on the best cream to use and can prescribe those that aren’t available over the counter.

It‘s important to keep the area as clean as possible to help prevent infection. The area should be washed gently. Your nurse can let you know which product to wash the area with, as many soaps and shower gels may cause irritation. After washing, the area should be patted dry (not rubbed) with a clean, soft towel. If patting with a soft towel is too painful, a cool hairdryer or electric fan can be used to dry the area. If your skin becomes infected you may be given antibiotics, either as tablets or as a cream.

Fluid loss

You may lose a lot of fluid through your fistula if it is affecting the bowel - especially the small bowel. This can lead to dehydration and can affect the balance of nutrients in the body. If you’re losing a lot of fluid, you will be encouraged to drink plenty of liquid and may be given fluids by a drip (infusion) into a vein (intravenously). You may also be given artificial feeding in the same way.

A group of drugs called somatostatin analogues is sometimes used along with fluid replacement to slow down the amount of fluid that is lost. They help increase the amount of fluid and nutrients absorbed in the bowel and reduce the natural secretions that are produced. Somatostatin analogues (such as octreotide) are given by injection under the skin (subcutaneously) or into a vein (intravenously).


It’s possible to become poorly nourished if you are losing a lot of fluid from the bowel – especially the small bowel. A dietitian can give you advice about the best way to maintain your nutrition while slowing down the amount of leakage. It may help to have a low-fibre diet, but your dietitian can advise you about this. It may be necessary to feed you with a drip into a vein. This is called parenteral nutrition and is sometimes used before surgery.

Continence advice

If you are having problems with abnormal leakage of urine or loose bowel motions, it can be distressing and embarrassing. Your nurse can help by giving you advice about incontinence pads and aids, and by giving you emotional support. You can ask to be referred to a continence adviser or a stoma nurse. It may also be helpful to contact either the College of Sexual and Relationship Therapists or The Bladder and Bowel Foundation.

Pain control

If you have pain or soreness due to broken, sore or infected skin, tell your doctor or nurse. They can prescribe effective painkillers and anaesthetic creams that can help relieve your symptoms.


If you have diarrhoea or are constipated, changing your diet may help. A dietitian or specialist nurse can give you further advice. Avoiding too much fibre and eating small meals made from light foods can often slow diarrhoea down. Anti-diarrhoea tablets can also help. If you have constipation, increasing the amount of fluid you drink and eating a diet high in fibre can often help relieve it. Laxatives, and sometimes enemas, may also be needed. Your doctor or nurse will give you more advice.

Leakage from the fistula

If the fistula opens on to your skin there may be a discharge from it, which will need to be collected and contained. Dressings can be used to contain the discharge. But if there’s a large amount of it, a drainage bag can be used. The bag is stuck on to the skin, over the area where the fistula opens on to the skin.

Your doctor, specialist nurse or community nurse will be able to advise you on the best way to manage any discharge from your fistula. You or your carers can be taught how to change the dressings or manage the drainage bag. If you are at home and need help with this, a district nurse will be able to visit you and provide support.

Unpleasant smell

Sometimes a fistula can smell unpleasant. Many people find this symptom the most distressing.

Different dressings may help control an unpleasant smell. Some contain silver, which can reduce the number of bacteria in the wound and control the smell. Charcoal dressings can help filter any smell.

If there’s an infection in the fistula, antibiotics can help control it. Applying antibiotic gels directly on to the area can also help. Your doctor or nurse will be able to tell you more about this.

Often people feel self-conscious about an unpleasant smell, particularly when they're with other people. Air fresheners, environmental air filters and aromatherapy oils may disguise unpleasant smells and can help you feel more comfortable with family and friends.