What is pseudomyxoma peritonei?
Pseudomyxoma peritonei (PMP) is a rare tumour that grows slowly and causes a build-up of mucin (a jelly-like substance) in the abdomen and pelvis, giving rise to the name “jelly belly”.
PMP often starts in the appendix but can also start in other organs such as the large bowel and ovary. While it doesn’t spread to other parts of the body, PMP can put pressure on important organs as it continues to grow and this may cause problems.
PMP is rare. It is more likely to be diagnosed in people aged 40 years or over.
Women may be diagnosed slightly more often and at an earlier stage than men, after a mass or lump is found in their ovary.
Pseudomyxoma peritonei signs and symptoms
PMP is difficult to detect, and symptoms may take a while to develop. Symptoms that some people may experience include:
abdominal or pelvic pain
gradual increase in waist size
changes in bowel habits
loss of appetite.
Causes of pseudomyxoma peritonei
The causes of PMP are not known. There are no clear risk factors and it does not appear to run in families.
Diagnosis of pseudomyxoma peritonei
If your doctor thinks that you may have PMP, they will perform a physical examination and carry out certain tests.
If the results suggest that you may have PMP, your doctor will refer you to a specialist who will carry out more tests. These may include:
Blood tests will include a full blood count to measure your white and red blood cells,, your platelets and chemicals produced by cancer cells (tumour markers).
Special machines are used to scan and create pictures of the inside of your body. You may have an injection of dye into your veins before the scan which makes the pictures clearer. During the scan you will lie on a table which moves in and out of the scanner. A CT scan takes about 10-30 minutes.
An MRI scan produces detailed cross-sectional pictures of your body and can show the extent of any tumours. You will lie on a table which slides into a large metal tube that is open at both ends. An MRI scan takes about 30-90 minutes.
Soundwaves are used to create pictures of the inside of your body. You will be asked to lie down and a gel will be spread over the affected part of your body and then a small device (transducer) is moved over the area. The ultrasound takes about 15 minutes and is painless.
In a laparoscopy, a thin tube with a camera on the end (laparoscope) is inserted under sedation into the abdomen to view inside the cavity.
If your doctor sees any abnormal or unusual-looking areas they may remove a small sample of the tissue for closer examination. This is known as a biopsy. A pathologist will look at the sample under a microscope to check for signs of disease or cancer.
Treatment for pseudomyxoma peritonei
The main treatments for PMP are surgery and chemotherapy and can. be given alone or in combination.
PMP may not be treated straight away if the tumour is small and growing slowly; in this case it will be observed and monitored regularly, an approach known as active surveillance.
PMP is usually treated with surgery: either cytoreductive surgery followed by chemotherapy, or if the cancer cannot be treated effectively debulking surgery may be used instead to remove as much of the tumour as possible to reduce symptoms. Debulking surgery may be done again if the tumour grows back.
Chemotherapy is the use of drugs to kill or slow the growth of cancer cells. You may have one chemotherapy drug, or a combination of drugs. This is because different drugs can destroy or shrink cancer cells in different ways.
There are different types of chemotherapy used to treat PMP:
- Local chemotherapy –the chemotherapy drugs are delivered directly to the cancer.
- Systemic chemotherapy –the chemotherapy drugs enter the bloodstream and travel throughout the body in order to target rapidly dividing cancer cells in the tissues and organs. This type of chemotherapy can be given into a vein (intravenously) or as a tablet.
Radiation therapy (radiotherapy)
Radiation therapy (also known as radiotherapy) uses high energy rays to destroy cancer cells.
In some cases of PMP, your medical team may talk to you about palliative care. Palliative care aims to improve your quality of life by alleviating symptoms of cancer.
As well as slowing the spread of PMP, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.
Treatment TeamDepending on your treatment, your treatment team may consist of a number of different health professionals, such as:
- GP (General Practitioner) - looks after your general health and works with your specialists to coordinate treatment.
- Surgeon- surgically removes tumours and performs some biopsies.
- Medical oncologist - prescribes and coordinates the course of chemotherapy.
- Radiation oncologist - prescribes and coordinates radiation therapy treatment.
- Cancer nurse - assists with treatment and provides information and support throughout your treatment.
- Dietitian - recommends an eating plan to follow while you are in treatment and recovery.
- Physiotherapist/occupational therapist- help with physical and practical problems such as restoring movement and mobility after treatment.
- Other allied health professionals - such as social workers, pharmacists, and counsellors.
Screening for pseudomyxoma peritonei
Currently there is no national screening program for PMP in Australia.
Preventing pseudomyxoma peritonei
As the causes of PMP are not known there is no prevention advice specific to this disease.
Prognosis for pseudomyxoma peritonei
It is not possible for a doctor to predict the exact course of a disease, as it will depend on each person's individual circumstances. However, your doctor may give you a prognosis - the likely outcome of the disease - based on the test results, the rate of tumour growth, as well as your age, fitness and medical history.
Understanding Appendix Cancer and Pseudomyxoma Peritonei (PMP). Cancer Council Australia © 2021. Last medical review of the source fact sheet: February 2021.
This web-based resource was made possible by the Cancer Australia Supporting people with cancer Grant initiative, funded by the Australian Government.