This information is about a type of cancer called pseudomyxoma peritonei (PMP) which is a rare, slow growing cancer of the appendix.
Pseudomyxoma peritonei usually begins as a small polyp-like growth, called an adenoma. It starts in the appendix. Over time, this adenoma breaks through the wall of the appendix and spreads tumour cells to the lining of the abdominal cavity (the peritoneum). These cells produce mucus, which then collects in the abdomen as a jelly-like fluid called mucin.
There are three main ways in which most cancers spread: directly into nearby tissue or organs; through the bloodstream; or through the lymphatic system into the lymph nodes.
PMP does not spread in any of these ways. It spreads along the internal surfaces of the abdomen. The mucus collects in the peritoneum and causes symptoms. It can be many years before symptoms from this type of cancer become obvious.
The cause of PMP is unknown.
Signs and symptoms
Most people don’t have any symptoms for a long time. When symptoms occur they may include any of the following:slow increase in waist size hernia (a swelling on the abdomen) loss of appetite unexplained weight gain abdominal or pelvic pain changes in bowel habitsappendicitis.
Most people with these symptoms will not have PMP; however, it is important to have any symptoms checked by your doctor.
How it is diagnosed
Pseudomyxoma peritonei can be difficult to diagnose. It may be found during investigations into abdominal symptoms, or it may be discovered at the time of an operation for different problems.
CT (computerised tomography) scan:
This is a series of x-rays which build up a three-dimensional picture of the inside of the body. The scan is painless and can help to find where the tumour started and check whether it has spread within the abdomen.
Most people who have a CT scan are given a drink or injection to allow particular areas to be seen more clearly.
For a few minutes, this may make you feel hot all over. It is important to tell your doctor and the person doing this test if you are allergic to iodine or have asthma before having the injection or drink. It is usually still possible to have the injection if you have treatment to prevent an allergic reaction.
Sometimes the pictures from the CT are enough to make the diagnosis but sometimes biopsies, or an operation, are needed to be sure of the diagnosis of PMP.
Types of treatment
The treatment of PMP depends on a number of factors. These include how far the tumour has spread, and your general health. Some of the standard cancer treatments, such as radiotherapy, are not suitable for treating PMP. This is because PMP cells are not sensitive to radiotherapy and they are often spread over too large an area for this treatment.
You are most likely to be offered surgery to treat this kind of cancer. There are two types of surgery:debulking surgerycomplete tumour removal with heated intraperitoneal chemotherapy (this is known as the Sugarbaker technique).
Debulking surgery is an established treatment and aims to remove as much of the tumour as possible. This may involve removing part of the bowel and, in women, removing the womb and ovaries. Unfortunately it is unlikely that this surgery will take away all the tumour cells. Eventually the PMP is likely to grow back, which means that more debulking operations will be required. Each operation becomes more difficult to do as complications, such as adhesions, are more likely to develop. Adhesions are internal scar tissue which make the abdominal tissue stick together, causing pain.
For some people with PMP, an intensive type of surgery which aims to remove all traces of the cancer may be best. This is known as cytoreductive surgery or the Sugarbaker technique (named after the surgeon who first developed it). It involves stripping the lining of the abdomen and removing other abdominal organs such as the gallbladder and omentum. In women, the womb and ovaries are also removed.
If the surgeon has removed all, or most, of the tumour, a heated chemotherapy drug (mitomycin C) is put in the abdomen while you are under the anaesthetic to kill any tumour cells that can’t be seen. In some treatment centres, another drug (called 5FU) may also be given into your abdomen for up to five days following the surgery. This method of giving chemotherapy is known as heated intraperitoneal chemotherapy – HIPEC.
The Sugarbaker operation takes a long time (around 10 hours). Afterwards you will be nursed in intensive care or a high-dependency unit for several days and will stay in hospital for about two to three weeks. Results from specialist centres which treat PMP suggest that about one in three people will have serious complications from the surgery. About one in five people need further surgery to deal with complications from the first operation. About one in five people need a stoma (colostomy) after surgery. In about half of these people, the stoma is temporary and will only be needed for 3–6 months.
Regular chemotherapy (chemotherapy given as an injection in the vein or as tablets) is not often used to treat PMP. Other research into treatments for PMP is ongoing and advances are being made. Cancer doctors use clinical trials to assess new treatments. You may be asked to take part in a clinical trial. Your doctor must discuss the treatment with you so that you have a full understanding of the trial and what it means to take part.
For some people, the risks of treatment may outweigh the potential benefits, especially as this can be a slow-growing cancer. If this is your situation, your specialist may suggest watchful waiting. This involves being monitored closely with regular checkups. Only if the PMP begins to cause you problems will your specialist discuss starting treatment for you.
During diagnosis and treatment, you may experience many different emotions including anger, resentment, guilt, anxiety and fear. These are all normal reactions and are part of the process many people go through in trying to come to terms with their illness.
It can be difficult to find support if you have a rare cancer. Some people find it helpful to share their experiences at a local cancer support group.
Others may want to contact people with the same condition. Internet support groups provide resources and support to people with rare intestinal cancers like PMP.
The two national treatment centres for PMP can also provide contact details for people wishing to speak to others that have been through the treatment journey.