What is pseudomyxoma peritonei?
Pseudomyxoma peritonei is a very rare type of cancer that usually begins in your appendix as a small growth, called a polyp. Or, more rarely, it can start in other parts of the bowel, the ovary or bladder. This polyp eventually spreads through the wall of your appendix or wherever else it starts. It then spreads cancerous cells to the lining of the abdominal cavity (the peritoneum). These cancerous cells produce mucus, which collects in the abdomen as a jelly like fluid called mucin.
How pseudomyxoma peritonei spreads
Pseudomyxoma peritonei does not act like most cancers and does not spread through the bloodstream or the lymphatic system. It spreads inside the abdomen. The mucus collects inside the abdomen and causes symptoms. It develops very slowly and it may be many years before you have any symptoms from this type of cancer.
Symptoms of pseudomyxoma peritonei
Symptoms can include:
- Abdominal or pelvic pain
- Not being able to become pregnant
- Abdominal swelling and bloating
- Changes in bowel habits
Some people will not have any of these symptoms, so pseudomyxoma peritonei can be difficult to diagnose. In women, this type of cancer can sometimes be confused with ovarian cancer because ovarian cancer may also cause a swollen abdomen. Some types of ovarian cancer cells also produce mucin. Often, it is only after an operation to look into the abdomen (a laparotomy) that pseudomyxoma peritonei is properly diagnosed.
The treatment for pseudomyxoma peritonei (PMP) depends on the size of the tumour and your general health. Your doctor may recommend any of the following treatments:
Surgery combined with chemotherapy into the abdomen
If possible, you will have surgery combined with chemotherapy into the abdomen. The procedure is called cytoreductive surgery or the Sugarbaker technique, after the doctor that developed it. This removes most or all of the visible tumour in your abdomen. The surgeon strips out the lining of the abdomen (the peritoneum) and removes any tissues inside the abdomen affected by PMP. This varies between people, but can include the small bowel, large bowel, spleen, or liver. In women the surgeon may also remove the womb and ovaries.
After the surgeon has removed all signs of tumour, you have chemotherapy directly into your abdomen (intraperitoneal chemotherapy). This means putting the chemotherapy drugs straight inside the abdominal cavity where they can directly come into contact with the cancer cells. You may have a heated solution of chemotherapy put into your abdomen during and after your operation. After your surgery, you may have more intraperitoneal chemotherapy put into your abdomen for 4 days. The aim of this treatment is to kill off any tumour cells left behind after the surgery. The aim is to reduce the risk of it coming back.
The operation itself is long and can last 10 hours or more. It can take quite a while to recover because of the length of surgery and the removal of any organs affected by the cancer. Sometimes people need multiple operations, several months apart.
This intensive surgery is not suitable for everyone. The surgery takes a very long time and you may be in intensive care or a high dependency unit for up to 5 days. You are likely to be in hospital for 2 to 3 weeks. About 3 out of every 10 people (30%) have serious complications after treatment. About 1 out of 5 patients (20%) need a stoma after surgery. But about half of these people only need the stoma for 3 to 6 months.
The National Institute for Health and Care Excellence (NICE) has produced guidance on this intensive surgery with intraperitoneal chemotherapy. They recommend that it is only carried out in very specialised centres. Doctors must discuss the risks and benefits of the treatment with patients before they agree to have it.
Wait and watch
If your tumour is small and slow growing your doctor may decide to take a wait and watch approach. They may suggest chemotherapy or surgery in the future if it continues to develop.
This type of surgery removes as much of the tumour as possible. It will not cure the pseudomyxoma peritonei but reduces symptoms and can help people to feel comfortable for as long as possible. This might mean removing your womb and ovaries if you are a woman and sometimes part of your bowel. Unless you have cytoreductive surgery, it is hard to remove all of the tumour, so the tumour will come back. Often, several debulking surgeries will be required.
If cytoreductive surgery is not a viable option you may undergo chemotherapy to kill the cancer cells.
Specialist centres for pseudomyxoma peritonei
Because pseudomyxoma peritonei is very rare, it is advisable to seek out a specialist centre for treatment. Many people with pseudomyxoma peritonei will have already had surgery at another hospital because the condition wasn't suspected to begin with. Even if you have already had surgery, your specialist may recommend further surgery, followed by intraperitoneal chemotherapy. Your surgeon may refer you to a specialist centre for a second opinion. Or you can request a second opinion yourself.
For more information on Pseudomyxoma Peritonei click here
This link is to the MacMillan cancer website in the United Kingdom. There may be references to drugs and clinical trials that are not available here in Australia.