Pseudomyxoma peritonei (PMP)

What is pseudomyxoma peritonei (PMP)?

Clinical Oncologist Katherine Aitkens explains bowel cancer (which includes PMP), giving an overview of bowel cancer symptoms, diagnosis and treatment.

Pseudomyxoma peritonei (PMP) is a rare cancer that often grows slowly. It usually starts in the appendix. Sometimes it starts in another part of the bowel, the bladder or the ovaries but this is rare. We do not know what causes PMP.

The digestive system

PMP can spread from the appendix (or wherever it started) into the abdomen. PMP makes a jelly-like substance called mucin. The mucin collects in a layer of tissue that lines the inside of the abdomen, called the peritoneum. The peritoneum covers and protects the organs in your abdomen, such as the bowel. It also makes gaps around the organs. These gaps are called the peritoneal space.

The peritoneum, peritoneal space and abdominal organs (in women)

It may be many years before you have any symptoms. Eventually the build-up of mucin puts pressure on the bowel and other organs. PMP usually stays within the peritoneal space.

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Bowel cancer

Symptoms of pseudomyxoma peritonei

Some of the symptoms of PMP include:

gradual increase in waist size
a hernia (a bulge on the tummy wall)
loss of appetite
unexplained weight gain
tummy (abdominal) or pelvic pain
a change in bowel habit.

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Diagnosis of pseudomyxoma peritonei

PMP can be difficult to diagnose. You may have some of the symptoms listed above and go for tests. But PMP is often found when having tests or during treatment for other medical conditions. The following tests may be used to diagnose PMP.

CT scan

A CT scan uses x-rays to build a 3D picture of the inside of the body.
Ultrasound scan

An ultrasound scan uses sound waves to build up a picture of the internal organs onto a computer screen.
Drainage of fluid from the abdomen (peritoneal aspiration)

Your doctor may take a sample of fluid from your tummy to be tested. They will numb the skin over the area first with a local anaesthetic. The doctor will then pass a needle through the skin into the peritoneal space. They will use the needle to draw some of the fluid into a syringe.

You may also have a biopsy. This is when the doctor removes a small piece of tissue or cells. A doctor who specialises in analysing cells (pathologist) examines the tissue or cells under a microscope to look for signs of cancer. A biopsy can be taken in different ways:

CT or ultrasound-guided biopsy

A local anaesthetic is used to numb the area first. Your doctor passes a needle through the skin. They use an ultrasound or a CT scan to check the needle is in the right place. The needle has a tip that can cut out a small piece of tissue.
Surgery

A biopsy may be taken during keyhole surgery (laparoscopy). You have either a general anaesthetic or a local anaesthetic and a drug to make you feel relaxed and sleepy.
The surgeon makes a small cut in your tummy (abdomen). They use a special instrument called a laparoscope to look around inside your tummy. A laparoscope is a thin tube with an eyepiece at one end and a light and camera at the other end. Your doctor then uses another instrument to take a small piece of tissue.

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Treatment for pseudomyxoma peritonei

The main treatments for PMP are surgery and chemotherapy. Your treatment may depend on how far the PMP has spread and your general health.

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

Cytoreductive surgery with HIPEC

Cytoreductive surgery with HIPEC is an operation that aims to remove the PMP. It is also called the Sugarbaker technique, after the surgeon who first developed it.

It is major surgery, so it is important to discuss whether it is suitable for you with specialist doctors. After the surgery, you will stay in a critical care unit for a few days and in hospital for about 2 to 3 weeks. There are only two centres in the UK that offer cytoreductive surgery with HIPEC. If you have a long distance to travel, you may need to stay in hospital a bit longer.

The two specialist centres that do cytoreductive surgery with HIPEC in the UK are:

the Basingstoke and North Hampshire Hospital
the Christie Hospital in Manchester.

The aim of the operation is to remove as much of the PMP as possible. This often means removing:

the gallbladder
parts of the peritoneum, including the omentum
the spleen
in some cases, part of the bowel.

In women, the surgeon may also remove the womb (uterus) and ovaries.

When the surgeon has removed all signs of PMP, they put a heated chemotherapy liquid into the peritoneal space. This is called hyperthermic intraperitoneal chemotherapy (HIPEC).

Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. The aim is to kill any cancer cells that are left behind. After 60 to 90 minutes, the chemotherapy liquid is drained from the abdomen and the surgeon finishes the operation.

Some people will have more chemotherapy given into their peritoneal space during the first 5 days following the operation. A nurse or doctor will give this through tubes put into your abdomen.

Some people will have a stoma as part of the operation. A stoma is an opening that is made through the tummy wall (abdominal wall) and connects to a part of the bowel. Stools (poo) will no longer pass out of the rectum and anus. Instead, it will pass out of the stoma into a disposable bag that is worn over it. The stoma is round or oval and usually looks pink and moist. It has no nerve supply, so it does not hurt.

The stoma may be temporary. This means it can be reversed with a small operation after 3 to 6 months when you have recovered from surgery. Sometimes a stoma may be permanent.

A stoma and colostomy bag

Debulking surgery

If it is not possible to remove all the PMP with cytoreductive surgery, you may have a type of surgery called debulking surgery. This is when the surgeon removes as much of the PMP as possible. They may also remove the omentum (part of the peritoneum) and part of the bowel. In women, they may remove the womb (uterus) and ovaries.

The aim of this surgery is to reduce the symptoms. This treatment will not remove all of the PMP. You may need to have more debulking surgery later.

It is common to have a permanent stoma after debulking surgery. This can help prevent the bowel from becoming obstructed (blocked).

Chemotherapy

If you cannot have surgery, you may have chemotherapy to slow the growth of PMP and to reduce symptoms. You have chemotherapy as tablets, or as a drip (infusion) into a vein.

Watchful waiting

PMP can be slow-growing. Because of this, the risks of treatment may outweigh the possible benefits for some people. In this situation, your doctor may suggest watchful waiting. This means you do not need to start treatment straight away.

You will have CT scans, blood tests and regular check-ups to monitor the PMP and your symptoms. If the PMP begins to cause you problems, your doctor will talk to you about starting treatment.

Clinical trials

You may have some treatments as part of a clinical trial. But, because PMP is rare, there may not always be a trial in progress.

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After pseudomyxoma peritonei treatment

Your feelings

You may have many different emotions. You may feel shock, disbelief, fear and anger. It can be hard to manage these feelings at times and it is normal to feel overwhelmed.

Everyone has their own way of coping. Some people find it helpful to talk to family or friends. Others get help from people outside their situation. Sometimes it is helpful to share your experiences at a local cancer support group. There is no right or wrong way to cope, but help is there if you need it.

Getting support

Some people with a rare type of cancer may find it helpful to talk to someone with the same condition. Your specialist doctor may be able to put you in touch with someone who has PMP and is happy to speak to others. There is an organisation called Pseudomyxoma Survivor who can also help with this.

Macmillan is also here to support you. If you would like to talk, you can:

Call the Macmillan Support Line on 0808 808 00 00.
Chat to our specialists online.
Visit our pseudomyxoma peritonei forum to talk with people who have been affected by pseudomyxoma peritonei (PMP), share your experience, and ask an expert your questions.

About our information

References

Below is an example of a source used in our pseudomyxoma peritonei information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

NICE Interventional procedures guidance [IPG56]. Complete cytoreduction for pseudomyxoma peritonei (Sugarbaker technique). www.nice.org.uk/guidance/ipg56 (accessed May 2019).

Reviewers

This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.