What is peritoneal mesothelioma?
Peritoneal mesothelioma is a rare type of cancer affecting your peritoneum. Your peritoneum is a membrane that lines your abdominal cavity and organs, like your liver and intestines. Like other types of mesothelioma, peritoneal mesothelioma can be related to prior asbestos exposure. Asbestos is a type of building material that’s harmful when inhaled or ingested (swallowed).
Peritoneal mesothelioma is an aggressive form of cancer because it has often spread throughout your abdominal lining at diagnosis and is difficult to detect early.
What is the difference between peritoneal mesothelioma and pleural mesothelioma?
Peritoneal mesothelioma and pleural mesothelioma form in the lining that protects important body cavities and internal organs. Peritoneal mesothelioma forms in the membrane that lines your abdominal cavity and covers your abdominal organs (peritoneum). Pleural mesothelioma forms in the membrane that lines your chest cavity and protects your lungs (pleura). Both membranes consist of mesothelial cells. This is where the name mesothelioma comes from.
Both types of mesothelioma are usually malignant (cancerous). Malignant mesothelial cells grow out of control and harm surrounding healthy tissue. Pleural mesothelioma is more common than peritoneal mesothelioma.
Who does peritoneal mesothelioma affect?
Anyone can be affected by peritoneal mesothelioma, although it’s rare in children. Most people get diagnosed in their 50s.
How common is peritoneal mesothelioma?
Peritoneal mesothelioma is the second most common type of mesothelioma (right behind pleural mesothelioma), but it’s still rare. Only 10% to 20% of all mesothelioma diagnoses are peritoneal mesothelioma. As few as 400 to 1,000 new cases get diagnosed in the United States each year.
Symptoms and Causes
What are the symptoms of peritoneal mesothelioma?
Peritoneal mesothelioma often doesn’t cause symptoms until it’s spread to organs in your abdominal cavity. The most common symptom is fluid build-up in your abdomen. As the fluid collects, your abdomen may get bigger. Abdominal pain is the second most common symptom.
Signs and symptoms of peritoneal mesothelioma include:
- Fluid build-up in your abdomen (ascites).
- Swelling or bulging in your abdomen.
- Pain that feels spread out in your abdomen (most common) or local to one spot (less common).
- A painful mass in your pelvic area.
- Constipation or bowel obstruction (blockage).
- Nausea and vomiting.
- Fever and night sweats.
- Unexplained weight loss.
- Loss of appetite.
What causes peritoneal mesothelioma?
The biggest risk factor for mesothelioma is asbestos exposure. Asbestos is a fiber used in professions like construction, plumbing, electrical work, roofing, manufacturing and the automotive industry. Many people with mesothelioma work in occupations that expose them to asbestos.
Although most people diagnosed with pleural mesothelioma have a history of asbestos exposure, the connection between asbestos and peritoneal mesothelioma isn’t as straightforward. Many people diagnosed with peritoneal mesothelioma don’t work in professions that expose them to asbestos.
More research is needed to understand the relationship between asbestos and peritoneal mesothelioma.
Risk factors for peritoneal mesothelioma include:
- Asbestos exposure: When asbestos fibers are disturbed, they get released into the air. Once airborne, they can enter your body through your mouth and nose, travel to your peritoneum and embed there. Once they’ve settled into the lining, asbestos fibers can damage mesothelial cells, causing them to divide abnormally. These cells can form tumors that harm nearby healthy tissue. People exposed to asbestos may not develop mesothelioma until several years (up to forty years) after exposure.
- Silica and erionite exposure: Silica and erionite are common minerals in the earth. Exposure has been linked to pleural and peritoneal mesothelioma.
- Gene mutations: Studies have shown that specific gene mutations (changes) may increase your risk of developing peritoneal mesothelioma if you’ve also been exposed to asbestos. The most common mutation affects a gene called BAP1. BAP1 is a gene that prevents tumor growth.
- Radiation exposure: Previous radiation therapy to treat abdominal cancer may also increase your risk of peritoneal mesothelioma. More research is needed to understand the connection between radiation and mesothelioma risk.
Diagnosis and Tests
How is peritoneal mesothelioma diagnosed?
Peritoneal mesothelioma can be challenging to diagnose because it often doesn’t produce symptoms in the early stages. When symptoms do arise, they’re usually similar to other, more common, conditions affecting your gastrointestinal (GI) tract, as well as other cancers. Diagnosis often involves ruling out these more common conditions.
Diagnosis may include:
- Computed tomography (CT) scan: Your healthcare provider may perform a CT scan to rule out conditions that cause symptoms similar to peritoneal mesothelioma, like ovarian cancer and adenocarcinoma. Your provider may inject a safe dye (contrast) into your bloodstream that makes masses in your abdomen stand out more on imaging.
- Magnetic resonance imaging (MRI): An MRI can show imaging details similar to a CT scan. You may receive an MRI if you can't receive a CT scan with contrast.
- Blood tests: Your provider can check for markers in your blood, like specific proteins, that may be signs of a tumor.
- Peritoneal fluid analysis: During this procedure, your provider inserts a needle into your abdominal cavity to collect a fluid sample to test for signs of mesothelioma. A limitation of this test is that it provides information on abdominal fluid but not abdominal tissue. The cancer’s impact on tissue determines how advanced your cancer is.
- CT-guided core needle biopsy or laparoscopic biopsy: A biopsy is the only way to confirm a peritoneal mesothelioma diagnosis. During the procedure, your provider will use imaging to locate the precise location of your tumor. They’ll use surgical instruments to remove a tissue sample for testing.
How is peritoneal mesothelioma staged?
Cancer staging shows how advanced the disease is. The PCI system is the most commonly used cancer-staging system for peritoneal mesothelioma.
The peritoneal cancer index (PCI) classifies your cancer by dividing your abdomen into 13 sections and assigning a number from 0 to 3 to each section. Zero means no cancer, while 3 means cancer has overtaken an area. Your provider adds the numbers for each section to determine the cancer stage. Stage 1 is the least advanced. Stage 4 is the most advanced.
- Stage 1: PCI score from 1 to 10.
- Stage 2: PCI score from 11 to 20.
- Stage 3: PCI score from 21 to 30.
- Stage 4: PCI score from 31 to 39.
Management and Treatment
How is peritoneal mesothelioma treated?
Treatment options depend on your cancer stage, your health and other factors.
Cytoreduction with HIPEC
The most common treatment for peritoneal mesothelioma is cytoreduction with hyperthermic intraperitoneal chemotherapy (HIPEC).
- Cytoreduction is a surgery that removes cancer cells in your abdomen. Your provider will remove all tumors. They’ll also remove parts of your peritoneum and abdominal organs where the cancer’s spread.
- Hyperthermic intraperitoneal chemotherapy (HIPEC) is a type of chemotherapy given after cytoreduction. The chemotherapy drugs are heated to a safe temperature and administered directly into your abdominal cavity. The heat causes the dose to be much stronger than standard chemotherapy. HIPEC kills any remaining cancer cells that may have gotten missed during surgery. HIPEC causes fewer side effects than standard chemotherapy.
Cytoreduction with HIPEC is a time-intensive procedure, lasting more than 10 hours. Still, research has shown that this treatment helps people with peritoneal mesothelioma live longer.
You may receive systemic chemotherapy if you’re not able to have cytoreduction with HIPEC. Systemic chemotherapy drugs travel through your bloodstream to kill cancer cells throughout your body. You may receive a combination of different types of systemic chemotherapy drugs.
Immunotherapy drugs called immune checkpoint inhibitors help your immune system locate and kill cancer cells. These types of drugs are commonly used to treat pleural mesothelioma. Your provider may also prescribe them to treat peritoneal mesothelioma treatment.
Some people with peritoneal mesothelioma may have genetic changes in their tumor cells that may be treated with targeted therapies. Targeted therapy targets the genetic changes that turn healthy cells into cancer cells. These treatments may be available to your treating oncologist or through studies that test the safety and effectiveness of new treatments called clinical trials. Your healthcare provider should perform gene testing on your tumor biopsy to find out if your tumor has any targetable gene changes.
Your provider may recommend palliative care to help you manage cancer symptoms and treatment side effects. Palliative care may be your best option if you’re not healthy enough for surgery or if your cancer’s in a later stage. Palliative care treatments may include a procedure called paracentesis. Paracentesis drains fluid from your abdomen, helping to relieve uncomfortable or painful pressure from fluid build-up.
How can I reduce my risk?
The only known way to reduce your risk of developing peritoneal mesothelioma is to avoid asbestos exposure. In the 1970s, the Environmental Protection Agency (EPA) began regulating how industries use asbestos. Many buildings built before the EPA regulations still contain asbestos. Asbestos fibers can be harmful if they’re disturbed and become airborne.
Reduce your risk by avoiding repairs or remodels that may expose you to asbestos. Instead, hire an expert, like an asbestos abatement professional, to handle jobs that involve working around this material.
Outlook / Prognosis
What can I expect if I have peritoneal mesothelioma?
Peritoneal mesothelioma can’t be cured, but treatment can prolong your life, and the disease can go through periods of remission. Working with a team of cancer specialists with expertise in treating mesothelioma can improve your treatment outcomes. Working with palliative care professionals can improve your quality of life as you navigate your cancer diagnosis.
What factors influence my prognosis?
Your prognosis depends on a variety of factors, including:
- The type of cell: Three potential cell types may become tumors. The most common cell type, epithelioid cells, has a better prognosis than the other cell types, sarcomatoid cells and biphasic cells.
- Your mesothelioma stage: Mesothelioma that’s diagnosed and treated in its early stages is associated with more positive outcomes.
- Your sex: Women and people assigned female at birth tend to have a better prognosis with peritoneal mesothelioma than men and people assigned male at birth.
- Tumor removal: Your prognosis is better if your provider is able to completely remove all tumors.
- Thrombocytosis: You may have a worse prognosis if you have thrombocytosis. Thrombocytosis is a condition that involves having too many platelets in your blood. Platelets are cells that help your blood clot.
How long can you live with peritoneal mesothelioma?
People diagnosed with peritoneal mesothelioma live from six months to a year without treatment. Survival rates are much better with treatment. People with peritoneal mesothelioma who receive cytoreductive surgery and HIPEC live from two to six years after their diagnosis.
Still, your prognosis depends on multiple factors. Your provider is your best resource for understanding which factors will shape your prognosis based on your treatment options.
What questions should I ask my doctor?
- Which specialists will be involved in my care?
- Should I work with a palliative care team?
- What type of mesothelioma do I have?
- How advanced is my cancer?
- What are my treatment options?
- Are there clinical trials available to me?
- What outcomes should I expect based on available treatments?
- What treatment side effects should I expect, and how can I manage them?
A note from Cleveland Clinic
Work with your healthcare provider to discuss your treatment options if you’re diagnosed with peritoneal mesothelioma. There isn’t a cure for this type of cancer. Still, depending on factors like how advanced the cancer is and your general health, there are treatment options that can help you live longer. Treatments, including palliative care, can improve your quality of life as you navigate your cancer diagnosis.
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