Staging and prognosis for peritoneal mesothelioma

If mesothelioma is diagnosed, you will have tests to work out the extent of the disease and if it has spread to other parts of the body. This is called staging, and helps your health care team recommend the best treatment for you.

The main tests used are a CT or a PET–CT scan. If you already had a CT or PET–CT scan during diagnosis, which showed advanced disease, a further scan may not be necessary.

Learn more about:

• Staging systems for mesothelioma
• Tests before surgery
• Prognosis

Staging systems for mesothelioma

Staging can be difficult for mesothelioma. Doctors use the systems described below to stage the different types of mesothelioma.

PCI system for peritoneal mesothelioma

Peritoneal mesothelioma is usually staged using the peritoneal cancer index (PCI). The area of the abdomen and pelvis is divided into 13 regions. A score out of 3 is given to any tumours found in these regions. The PCI is calculated by adding together the scores for all 13 regions, with a maximum score of 39. The higher the PCI, the further the cancer has spread.

Tests before surgery

If radical surgery is being considered as a suitable treatment option (part of trimodal therapy), you may have other scans and procedures to check whether mesothelioma has spread to other areas of the body.

These tests may include:

FDG–PET – A positron emission tomography (PET) scan detects radiation from a low-level radioactive drug that is injected into the body. In an FDG–PET, the drug used is called fluorodeoxyglucose (FDG). The FDG shows up areas of abnormal tissue.

MRI scan – A magnetic resonance imaging (MRI) scan uses a powerful magnet and radio waves to create detailed, cross-sectional pictures of the soft tissues in your body. The noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention it beforehand to your medical team. You may be given a mild sedative to help you relax.

Surgical staging – If it is unclear from the PET–CT scan whether pleural mesothelioma has spread, the surgeon may remove a sample of lymph nodes and tissue from other areas of the body to check. This is known as surgical staging. It is not recommended before a peritonectomy for peritoneal mesothelioma.

Prognosis

Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis with your doctor, but it is not possible for anyone to predict the exact course of the illness.

Mesothelioma behaves differently in different people, which will affect prognosis. The disease is often there for many months before being diagnosed at an advanced stage. After diagnosis, mesothelioma may progress quickly or more slowly. If it progresses slowly, some people may live for several years or longer.

Your doctor will consider several factors when discussing prognosis with you, including:

• the type of mesothelioma cell
• the stage
• the type of treatment you are able to have
• your symptoms, such as weight loss or pain
• your blood count – people with normal levels of blood cells usually have a better prognosis
• your overall health – recovering quickly after procedures tends to suggest a better outcome.

While knowing the stage helps doctors plan treatment, it can’t always indicate a prognosis for people with mesothelioma. This is partly because it is hard to predict how quickly mesothelioma will grow. Usually the earlier the stage, the better the prognosis. If the mesothelioma has advanced to a point where it is unlikely to respond to treatment, the priority will be to relieve symptoms and improve your quality of life (see Palliative treatment).

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