Peritoneal mesothelioma develops in the lining of the abdomen (the peritoneum). It is the second most common form of cancer caused by asbestos, with approximately 500 cases diagnosed annually in the US.
Key Points about Peritoneal Mesothelioma
- Approximately 20 percent of all mesothelioma cases develop in the peritoneum.
- Asbestos likely reaches the abdomen through ingestion or via the lymphatic system.
- Early detection and aggressive treatment are the most effective options for surviving peritoneal mesothelioma.
Peritoneal mesothelioma, sometimes called abdominal mesothelioma, is one of several types of mesothelioma that develops in the lining of the abdominal cavity (known as the peritoneum). It accounts for about 15 – 20 percent of all mesothelioma cases diagnosed throughout the world, with approximately 500 cases in the U.S. diagnosed each year. It is the second-most common form of mesothelioma cancer, and while almost always fatal, has a more favorable prognosis than other types of mesothelioma. New treatments have extended survival times, with many patients living with the disease for seven years or more.
- Cause // Asbestos inhalation or ingestion
- Location // Abdominal lining (peritoneum)
- Common Symptoms // Abdominal pain
- Treatment // Surgery
- Prognosis // 6 – 12 months
What are the Symptoms of Peritoneal Mesothelioma?
Like all forms of asbestos-related cancer, peritoneal mesothelioma can lie dormant for up to fifty years, and its symptoms may be easily confused with those of other, more common diseases. Many victims go undiagnosed or are improperly diagnosed for months before the proper conclusion is determined.
- Abdominal pain (acute to severe)
- Swelling of the abdominal region due to fluid accumulation
- Breathing difficulties
- Loss of appetite and/or weight loss
- Bowel obstruction
Symptoms may vary depending on a number of factors, including:
- Tumor location and size
- Patient’s age
- General health of the individual
When presenting symptoms for diagnosis, it’s important to tell your doctor about any potential exposure to asbestos, even if it occurred many years ago. This may spare you a number of unnecessary tests and a long wait before beginning treatment.
How is Peritoneal Mesothelioma Diagnosed?
As with the more common pleural mesothelioma, diagnosis begins with imaging tests, such as an X-ray, MRI, CT scan, or PET scan. However, these tests can only show where malignant tumors may be formed.
After the imaging test(s), your doctor will perform additional tests, usually to rule out other diseases. A tissue biopsy is the only test that can make a conclusive diagnosis of peritoneal mesothelioma. The biopsy is performed using a peritoneoscopy or laparotomy to take a sample of the tissue around the abdominal cavity. The biopsy can be uncomfortable, but it is usually over in just a few minutes.
Once the biopsy is taken, a pathologist scrutinizes the sample tissue under a microscope to determine if the cells are cancerous, a process known as histological analysis. The pathologist will further categorize a mesothelioma tumor according to its cell type: epithelioid, sarcomatoid, or biphasic (a combination of the other two).
How is Peritoneal Mesothelioma Treated
Treating peritoneal mesothelioma usually requires a multimodal approach – that is, a combination of different techniques, usually surgery, radiation therapy, and chemotherapy. If the disease is diagnosed at a late stage, then some of these treatments may be palliative (designed to relieve pain) rather than curative.
- Most often successful in early stages of mesothelioma
- Peritonectomy: tumor removed by cutting portion of lining and tissue from abdominal area
- Large tumors may require removal of a lung or section of the diaphragm
- At diagnosis, peritoneal mesothelioma usually too advanced for surgery
- Most common treatment for peritoneal mesothelioma
- Hyperthermic intraperitoneal chemotherapy (HIPEC): new treatment that involves delivering chemotherapy drugs directly to the abdominal cavity
- HIPEC most effective when combined with cytoreductive surgery
- Traditional radiation therapy bombards abdomen with radiation from an external source
- Brachytherapy: radiation delivered through an internal source
- Can enhance the effectiveness of other treatments and relieve symptoms
- Applied as palliative treatment during late-stage peritoneal mesothelioma
Experimental treatments such as immunotherapy are riskier than traditional treatments but may offer hope to patients who respond poorly to conventional treatments.
- Uses the immune system to start or enhance the body’s natural immune responses to mesothelioma
- Can be used to target specific types of cells
- Usually employed in combination with conventional treatments
- Still only an option in clinical trials
- Research funding has increased as the number of mesothelioma cases has risen
- Test new treatments and combinations of therapies
- Outcomes are uncertain, but may offer eligible patients hope where conventional treatments do not
What are the Causes of Peritoneal Mesothelioma?
As with all types of mesothelioma, the primary cause of peritoneal mesothelioma to be exposure to asbestos. A very small number of people with a specific genetic predisposition may also develop peritoneal mesothelioma after prolonged exposure to erionite, a naturally occurring mineral similar to asbestos.
It’s unclear exactly how asbestos gets into the abdomen, but the two most common theories are lymphatic transport and ingestion.
Lymphatic Transport: A network of connected tissues and organs carries a fluid called lymph, which contains white blood cells, throughout the body. This lymphatic system is critical for helping to fight viruses, infection, and disease. Some experts believe that asbestos fibers enter initially through the lungs, and then are transported through the lymphatic system to the abdominal cavity, where they can become stuck in the peritoneum.
Ingestion: Asbestos fibers may be swallowed, either directly or after being trapped in mucus during inhalation. The body cannot digest asbestos, and as the fibers move through the digestive system, they may work themselves into the peritoneal cavity and, eventually, into the lining of the abdomen.
Asbestos fibers in the peritoneum can eventually cause inflammation and, ultimately, tumors. As the tumors grow, they begin to cover the abdominal cavity and eventually may spread (metastasize) to other areas of the body.