Peritoneal Mesothelioma Malignant

Peritoneal mesothelioma is a rare and aggressive cancer that affects the tissue lining the abdomen. While there is no cure, advances in treatment combining surgery and specialized chemotherapy have transformed survival from less than a year to several years for many patients.

Table of contents

• What Is Peritoneal Mesothelioma?
• Associated Anatomy
• How Common Is This Disease?
• Signs and Symptoms
• Causes and Risk Factors
• Diagnosis
• Treatment Options
• Outlook and Life Expectancy
• Prevention

What Is Peritoneal Mesothelioma?

Peritoneal mesothelioma is a rare type of cancer that develops in the peritoneum, which is the thin membrane that lines the abdominal cavity and covers abdominal organs like the liver, stomach, and intestines^[1]. The term “mesothelioma” comes from mesothelial cells, which are the cells that make up this protective lining^[1].

This cancer is considered malignant, meaning the diseased cells grow out of control and harm surrounding healthy tissue^[1]. Peritoneal mesothelioma is an aggressive form of cancer because it often spreads throughout the abdominal lining before it is detected, making early diagnosis difficult^[1].

Peritoneal mesothelioma differs from the more common pleural mesothelioma, which affects the tissue lining the chest cavity and lungs. Both types involve cancer of mesothelial cells, but they occur in different locations in the body^[1].

The disease typically stays within the abdominal cavity and rarely spreads to distant parts of the body. It can progress by directly extending through the diaphragm (the muscle that separates the chest from the abdomen) to reach the chest cavity^[2].

• Peritoneum (abdominal lining)
• Liver
• Intestines
• Stomach
• Kidneys
• Abdominal organs

How Common Is This Disease?

Peritoneal mesothelioma is the second most common type of mesothelioma, following pleural mesothelioma, but it remains very rare^[1]. Only 10% to 20% of all mesothelioma diagnoses are peritoneal mesothelioma^[1][5].

In the United States, approximately 400 to 1,000 new cases are diagnosed each year^[1][4]. The disease affects both men and women, with most people receiving their diagnosis in their 50s^[1]. While anyone can develop peritoneal mesothelioma, it is rare in children^[1].

Signs and Symptoms

Peritoneal mesothelioma often does not cause symptoms until the cancer has spread to organs within the abdominal cavity^[1]. Many symptoms do not appear until several decades after initial exposure to asbestos, sometimes up to 50 years later^[8].

The most common symptom is fluid build-up in the abdomen, called ascites. As this fluid collects, the abdomen may become swollen or enlarged^[1]. Abdominal pain is the second most common symptom^[1].

Common signs and symptoms include:

• Fluid build-up in the abdomen (ascites)
• Swelling or bulging of the abdomen
• Abdominal pain or discomfort (may feel spread out or localized)
• A painful mass in the pelvic area
• Constipation or bowel blockage
• Nausea and vomiting
• Fever and night sweats
• Unexplained weight loss
• Loss of appetite

Some less obvious symptoms may also indicate the presence of cancer, including anemia (decreased red blood cells), increased risk of blood clots, and small bowel obstruction^[8]. Many of these symptoms are similar to chronic digestive conditions like colitis or diverticulitis, which can lead to misdiagnosis^[8].

Causes and Risk Factors

The only proven cause of peritoneal mesothelioma is exposure to asbestos^[6]. Asbestos is a fiber that was commonly used in construction, plumbing, electrical work, roofing, manufacturing, and the automotive industry^[1].

When asbestos-containing materials are disturbed, tiny asbestos fibers become airborne and can enter the body through the mouth and nose. Once inhaled or swallowed, these fibers may travel to the abdomen and become lodged in the peritoneum^[1][5].

The body’s immune system cannot break down or remove asbestos fibers once they become trapped in tissue. Over many years, the fibers cause chronic irritation and inflammation. This repeated damage can lead to scar tissue formation and changes in cellular DNA, eventually causing tumors to form^[8].

However, the connection between asbestos exposure and peritoneal mesothelioma is not as straightforward as it is with pleural mesothelioma. Many people diagnosed with peritoneal mesothelioma do not have a history of working in occupations with known asbestos exposure^[1]. More research is needed to fully understand this relationship.

People who work in occupations that expose them to asbestos are at highest risk. Many patients with mesothelioma have occupational exposure to this material^[1].

Diagnosis

Diagnosing peritoneal mesothelioma can be challenging due to its rarity and nonspecific symptoms. The disease is usually diagnosed late when the disease burden is extensive^[2].

Diagnosis typically begins with a physical examination where a healthcare professional checks for lumps or other signs^[7]. Imaging tests are then used to look for evidence of mesothelioma, including:

• CT scans (computed tomography) of the chest and abdomen
• MRI (magnetic resonance imaging)
• PET scans (positron emission tomography)
• Ultrasound

A biopsy is the only way to confirm or rule out mesothelioma^[7]. During a biopsy, a small sample of tissue is removed for examination under a microscope. The biopsy may be done by inserting a needle through the skin or during a surgical procedure^[7].

The tissue sample is sent to a laboratory where tests can show whether the tissue is mesothelioma. Additional tests help determine the specific type of cells involved and whether the cancer has spread to lymph nodes or other areas of the body^[7].

Treatment Options

While there is no cure for peritoneal mesothelioma, several treatment options can improve prognosis and quality of life^[1]. Treatment is usually aimed at controlling the disease for as long as possible and managing symptoms^[12].

Surgery

Surgery is not suitable for everyone, and patients need to be very fit for this type of major operation^[12]. The main surgical approach is called cytoreductive surgery (CRS), also known as debulking surgery. This procedure aims to remove all visible evidence of disease^[2][13].

During cytoreductive surgery, surgeons may remove part or all of the peritoneum (the abdominal lining)^[12]. The goal is to reduce the amount of cancer in the body, which may help patients live longer and relieve symptoms.

Chemotherapy

Chemotherapy uses anti-cancer drugs to destroy cancer cells^[12]. It can be given in different ways:

Intravenous chemotherapy is delivered through a vein to shrink the cancer and control symptoms. Common drugs used for peritoneal mesothelioma include pemetrexed and cisplatin^[12].

Hyperthermic intraperitoneal chemotherapy (HIPEC) is a specialized treatment given directly into the abdomen during surgery. The chemotherapy is heated and circulated throughout the abdominal cavity while the patient is still in the operating room^[2][12]. This approach has become a mainstay of therapy and has been shown to improve survival^[2][13].

The combination of cytoreductive surgery with HIPEC has become the standard of care for patients with resectable disease^[9].

Supportive Care

Many patients may be too ill to undergo intensive surgery or chemotherapy. However, supportive care (also called palliative care) can help relieve symptoms such as pain, weight loss, and fluid in the abdomen^[12].

One common supportive treatment is abdominal paracentesis, a procedure to drain excess fluid from the abdomen. This can relieve discomfort and heaviness caused by ascites^[12].

Palliative care is managed by a team that may include doctors, nurses, physiotherapists, and dieticians who are experts in controlling symptoms of advanced cancer^[12].

Clinical Trials

Because existing treatments do not always work well for mesothelioma, doctors and researchers are actively working to improve treatment options. Patients may be asked if they would like to participate in a clinical trial to help develop new treatments^[12].

Outlook and Life Expectancy

Without treatment, the life expectancy for peritoneal mesothelioma is less than a year^[2][13]. The disease is universally fatal, typically from abdominal complications related to the spread of disease^[2].

However, treatment advances have significantly improved survival. The median survival for patients diagnosed with peritoneal mesothelioma is about 2.5 years^[5]. With aggressive treatment combining cytoreductive surgery and HIPEC, median survival has increased to more than 5 years^[13].

Some patients who receive surgery and heated chemotherapy have lived for more than 10 years^[8]. With additional chemotherapy protocols, 70% five-year survival has been reported^[16].

Life expectancy varies based on several factors including the stage of disease, cell type, sex, and response to treatment^[5]. Knowledgeable patient selection for treatment is essential to achieve the best outcomes^[2].

Prevention

The most important way to prevent peritoneal mesothelioma is to avoid exposure to asbestos. Since asbestos exposure is the primary risk factor, limiting contact with this material can reduce the risk of developing the disease^[1].

People who work in high-risk occupations should follow workplace safety guidelines and use protective equipment when working with or around asbestos-containing materials. If you believe you have been exposed to asbestos, inform your healthcare provider so they can monitor for early signs of disease.