What is the Peritoneum?

As mentioned, the peritoneum is the thin membrane which lines the abdominal and the pelvic cavities. The two cavity areas are referred to as the peritoneal cavity. The peritoneum also covers most organs in the abdominal areas, and that includes the intestinal tract while excluding the kidneys.  Even though the peritoneum is comprised of one continuous membrane, it has two layers These layers are the parietal peritoneum (cavity lining) and the visceral peritoneum (organ covering).  The visceral peritoneum is the inner layer around organs and the parietal peritoneum is the outer layer which attaches to the abdominal wall.

Between the two layers of the peritoneum is a layer of fluid that serves as a lubricant.  This fluid allows the layers to slide freely over each other and enables the organs to expand when full.  Together, the two peritoneal layers help support and suspend the abdominal and pelvic cavity organs.

How does Peritoneal Mesothelioma Occur? 

The only known cause of peritoneal mesothelioma at this time is asbestos exposure and is responsible for approximately 30 percent of mesothelioma incidences annually²   When asbestos enters the abdominal area, it embeds itself into the peritoneum.  Over time (often decades), the asbestos causes cells to mutate and become cancerous. Experts are still not exactly sure how the asbestos fibers cause peritoneal mesothelioma or cancer.  Researchers have 3 theories that suggest cancer is caused by the over-production of asbestos induced free radicals, by asbestos damaged chromosomes that are passed along during cell division, or by a process in which asbestos concentrates cancer inducing chemicals or proteins.³

There are two primary theories as to how the asbestos reaches to peritoneum.

• The asbestos was ingested, such as by eating food which was covered in asbestos dust. For example, workers may have ingested asbestos while eating their lunch at the asbestos-contaminated workspace.  Once ingested, the asbestos fibers move from the digestive system into the peritoneum.
• The asbestos was inhaled and absorbed into the blood stream and/or lymphatic system.  Over time, the asbestos fibers where carried to the digestive system where they became embedded in the peritoneum.

It is common for pleural mesothelioma (asbestos cancer of the lung/chest area) to be misdiagnosed as peritoneal mesothelioma if the cancer has spread from the chest cavity to the abdominal lining. Cancer is always identified by its original source.

Peritoneal Mesothelioma Symptoms and Diagnosis 

Symptoms of peritoneal mesothelioma usually do not occur until decades after asbestos exposure – as long as 30 years.  During this time, the asbestos causes mutations in the peritoneal cells, and the cells replicate and form multiple tumors.  The cancerous peritoneal cells may also produce excessive fluid in the peritoneum, layers in the abdominal area which can cause abdominal swelling.  However, before this swelling becomes apparent, abdominal pain usually occurs as the first symptom of peritoneal mesothelioma. Other symptoms include:

• Unusual weight loss
• Increasing waist size due to swelling from fluid accumulation
• Changes to bowel movements, such as become constipated or having diarrhea
• Exhaustion
• Chronic dyspepsia
• Perspiration
• Loss of appetite
• Unusual masses forming underneath skin around stomach

Because these symptoms are frequently also caused by other common ailments, many people do not seek medical attention and the peritoneal mesothelioma progresses.  If you are aware of asbestos exposure in the past, it is important to inform your doctor of these symptoms and your history of exposure.

Diagnosis of peritoneal mesothelioma typically begins with an image scan, such as an X-ray or CT scan.  The scan will be able to detect unusual growths or excess fluids.  Then peritoneal mesothelioma will generally be confirmed with a needle biopsy in which fluid is extracted or by a surgical tissue biopsy.  A needle biopsy is the least invasive procedure that involves drawing a sample of fluid to be analyzed in a lab for the presence of cancer cells.

After Peritoneal Mesothelioma Diagnosis 

If you are diagnosed with peritoneal mesothelioma, you will be presented with treatment options.  The goal of treatment is not to cure in most cases unless the mesothelioma was detected very early; it is to extend life and with as little pain as possible. The actual treatment of peritoneal mesothelioma is largely dependent on the stage of the cancer.  In the early stages of peritoneal mesothelioma, surgery may be effective.  However, most cases of peritoneal mesothelioma are not diagnosed until the later stages when chemotherapy is the most feasible treatment option.  Radiation therapy may also be used in combination with surgery and/or chemotherapy.

Patients diagnosed with peritoneal mesothelioma should be aware that they may be able to pursue legal actions and receive compensation.  There are already many trusts set up for compensating victims of asbestos exposure which leads to mesothelioma.  A qualified mesothelioma lawyer can help you seek compensation for medical and living expenses.  While financial compensation will not cure mesothelioma, it can make coping with your disease easier and provide your family with support.

References

¹ Galateau-Sallé MD, Francoise. (13 December 2010) Pathology of Malignant Mesothelioma. Caen, France: Springer.

² Bridda A, Padoan I, Mencarelli R, Frego M. (2007) Peritoneal mesothelioma: a review. MedGenMed; v9:32

³ Toyokuni, S. Mechanisms of asbestos-induced carcinogenesis. (7 Feb 2009) Nagoya Journal of Medical Science, v71(1-2): 1-10.