What is Peritoneal Mesothelioma?

The Peritoneum: Understanding the Affected Area

The peritoneum is a vital part of the abdominal cavity, consisting of two layers:

• Visceral Peritoneum: The inner layer that wraps around the abdominal organs.
• Parietal Peritoneum: The outer layer that lines the abdominal wall.

These layers create a protective sac that helps support the abdominal organs and contains a small amount of fluid that allows the organs to move smoothly against each other as the body moves. Peritoneal mesothelioma occurs when cancerous cells form in this lining, typically due to asbestos exposure. Learn more about the causes of mesothelioma.

Causes of Peritoneal Mesothelioma

The primary cause of peritoneal mesothelioma is exposure to asbestos, similar to other forms of mesothelioma. However, the way asbestos fibers reach the peritoneum differs from the process that leads to pleural mesothelioma.

Asbestos Exposure

• Ingestion: It is believed that asbestos fibers may be ingested, either directly through contaminated food or water or indirectly after being inhaled and subsequently swallowed. Once inside the digestive system, these fibers can lodge in the peritoneum, where they can cause inflammation and eventually lead to cancer.
• Migration from Lungs to Abdomen: Some researchers suggest that inhaled asbestos fibers could travel through the lymphatic system or blood to reach the abdominal cavity. For more information, see how asbestos exposure leads to mesothelioma.

Other Risk Factors

• Secondary Exposure: Similar to pleural mesothelioma, family members of workers exposed to asbestos may also be at risk due to secondary exposure, where asbestos fibers are brought home on clothing or skin.
• Environmental Exposure: In rare cases, people living near asbestos mines or factories may develop peritoneal mesothelioma due to environmental contamination.

Symptoms of Peritoneal Mesothelioma

Peritoneal mesothelioma symptoms can vary widely depending on the extent and location of the tumor. These symptoms often resemble those of other, more common abdominal conditions, which can lead to misdiagnosis. Learn more about common symptoms of mesothelioma.

Common symptoms include:

• Abdominal Pain: Persistent or severe pain in the abdomen is one of the most common symptoms.
• Abdominal Swelling (Ascites): The buildup of fluid in the abdominal cavity, known as ascites, can cause noticeable swelling and discomfort.
• Digestive Issues: Nausea, vomiting, and changes in bowel habits, such as diarrhea or constipation, are common as the cancer affects the digestive organs.
• Unexplained Weight Loss: Significant and unintentional weight loss is a frequent symptom.
• Fatigue: Generalized weakness and tiredness are common as the disease progresses.

Because these symptoms are not specific to peritoneal mesothelioma, they are often attributed to other gastrointestinal or abdominal conditions, which can delay diagnosis.

Diagnosis of Peritoneal Mesothelioma

Diagnosing peritoneal mesothelioma is challenging due to its rarity and the non-specific nature of its symptoms. The diagnostic process typically involves several steps. For more details, see Diagnosing mesothelioma.

Imaging Tests

• CT Scans: These scans provide detailed cross-sectional images of the abdomen, helping to identify abnormalities such as tumors or fluid buildup.
• MRI and Ultrasound: These imaging techniques can also be used to assess the extent of the disease and guide further diagnostic procedures.

Biopsy

• Paracentesis: In cases where ascites is present, a needle may be used to remove fluid from the abdominal cavity, which is then examined for cancer cells.
• Laparoscopy: A minimally invasive procedure where a camera and surgical instruments are inserted into the abdomen to obtain tissue samples directly from the peritoneum.

Pathology Tests

• Histopathology: Examination of the biopsy sample under a microscope to determine the presence and type of cancer cells. Peritoneal mesothelioma is typically classified into three histological subtypes: epithelioid, sarcomatoid, and biphasic (a combination of both).

Blood Tests

• Biomarkers: Certain biomarkers, such as mesothelin, may be elevated in individuals with mesothelioma, though these tests are not definitive for diagnosis.

Treatment Options for Peritoneal Mesothelioma

Treatment for peritoneal mesothelioma depends on several factors, including the stage of the disease, the patient’s overall health, and the specific characteristics of the cancer. Common treatment options include:

Surgery

• Cytoreductive Surgery: Also known as debulking surgery, this procedure involves the removal of as much of the tumor as possible. It is often combined with hyperthermic intraperitoneal chemotherapy (HIPEC).
• HIPEC: After cytoreductive surgery, heated chemotherapy drugs are directly circulated within the abdominal cavity to kill any remaining cancer cells. This targeted approach increases the effectiveness of chemotherapy while minimizing systemic side effects.

Chemotherapy

• Systemic Chemotherapy: For patients who are not candidates for surgery, systemic chemotherapy may be used to slow the progression of the disease and reduce symptoms. Learn more about how chemotherapy works for mesothelioma.

Palliative Care

• Symptom Management: For patients with advanced disease, palliative care focuses on relieving symptoms and improving quality of life. This may include procedures to drain excess fluid from the abdomen, pain management, and nutritional support.

Prognosis and Survival Rates

The prognosis for peritoneal mesothelioma varies significantly depending on several factors, including the stage at diagnosis, the patient’s overall health, and the response to treatment. The use of cytoreductive surgery combined with HIPEC has improved survival rates for some patients, with a median survival time ranging from 3 to 5 years for those who undergo this aggressive treatment. However, for patients with advanced disease who are not candidates for surgery, the prognosis remains poor, with a median survival time of about 12 to 21 months. Understand more about the prognosis for someone with mesothelioma.

Conclusion

Peritoneal mesothelioma is a rare and serious form of cancer that primarily affects the lining of the abdomen. Its symptoms can be vague and non-specific, often leading to delays in diagnosis. However, advances in treatment, particularly the combination of cytoreductive surgery and HIPEC, have offered hope for improved outcomes in some patients. Understanding the nature of peritoneal mesothelioma, its causes, and the available treatments is crucial for those affected by the disease and their families.

Sources:

• National Cancer Institute - Peritoneal Mesothelioma Overview
• American Cancer Society - Detailed Guide on Peritoneal Mesothelioma
• Centers for Disease Control and Prevention (CDC) - Asbestos and Mesothelioma