Definition and Overview
Peritoneal mesothelioma is a type of cancer that develops in the peritoneum, the thin membrane lining the abdomen and its organs. This rare cancer is the second most common form of mesothelioma, with only 200 to 400 cases diagnosed annually in the United States. It is known for its aggressive nature and rapid spread.
Differences from Pleural Mesothelioma
While peritoneal mesothelioma forms in the lining of the abdominal cavity, pleural mesothelioma develops in the lining of the chest cavity and lungs. Both types arise from mesothelial cells, but pleural mesothelioma is more common. The symptoms and treatment approaches can also differ between these two forms of mesothelioma.
Anatomy of the Peritoneum
The peritoneum consists of two layers: the visceral peritoneum, which covers the abdominal organs, and the parietal peritoneum, which lines the abdominal cavity. This membrane plays a crucial role in supporting and protecting the abdominal organs. When cancer develops in this lining, it can cause significant health issues, including pain and abdominal swelling.
Causes and Risk Factors
Asbestos Exposure
The primary cause of peritoneal mesothelioma is asbestos exposure. Asbestos fibers can be inhaled or swallowed, eventually reaching the peritoneum. Once there, they can cause inflammation and cellular damage, leading to cancer. Primary asbestos exposure occurs directly, while secondary exposure happens when asbestos fibers are transferred from the skin or clothing of someone who works with asbestos.
Genetic Factors
Genetics also play a role in the development of peritoneal mesothelioma. Certain gene mutations, such as the BAP1 germline mutation, can increase the risk of developing the disease. These genetic changes can make individuals more susceptible to mesothelioma, even with low levels of asbestos exposure.
Other Potential Causes
While asbestos is the main cause, other factors can also contribute to the risk of developing peritoneal mesothelioma. Radiation exposure from previous cancer treatments has been linked to a higher risk. Additionally, exposure to minerals like erionite and silica can also increase the likelihood of developing this rare cancer.
Symptoms and Early Signs
Common Symptoms
Peritoneal mesothelioma often presents with a range of symptoms that can be mistaken for other conditions. Early symptoms include abdominal pain or swelling and gastrointestinal issues, such as constipation or diarrhea. Other common symptoms are:
- Unexplained weight loss
- Loss of appetite
- Nausea and vomiting
- Fatigue and weakness
- Fluid buildup in the abdomen (ascites)
Rare Symptoms
In some cases, peritoneal mesothelioma can cause less common symptoms. These may include:
- Bowel obstruction
- Anemia
- Night sweats
- Fever
Why Symptoms are Often Delayed
Symptoms of peritoneal mesothelioma may not appear until decades after initial asbestos exposure. This long latency period makes early diagnosis challenging. Many people don’t experience symptoms until the disease has progressed to a more advanced stage. Additionally, the symptoms can be vague or intermittent, making it difficult to get a correct diagnosis. It’s important to talk to your healthcare provider if you have a history of asbestos exposure, even if you’re not yet experiencing symptoms.
Diagnosis and Staging
Initial Diagnostic Steps
Diagnosing peritoneal mesothelioma can be tricky because early symptoms are often absent or mimic other common conditions. Doctors usually start with imaging tests like CT scans or MRIs to look for abnormalities. Blood tests may also be done to check for specific proteins that could indicate a tumor. However, the only way to confirm the diagnosis is through a tissue biopsy.
Imaging and Biopsy
A CT-guided core needle biopsy is a less invasive way to obtain tissue and confirm peritoneal mesothelioma. In some cases, a more invasive surgical biopsy may be necessary. This happens when the tissue in question is difficult to reach, or the routine biopsy cannot gather enough cells to give your medical team a firm diagnosis. During this procedure, a surgeon uses a camera to look inside the abdominal cavity and choose the best location to biopsy.
Staging of Peritoneal Mesothelioma
Staging helps doctors understand how far the disease has spread and plan the best treatment. There is no official staging system for peritoneal mesothelioma, but many doctors use the TNM system. This system considers the size of the tumor, whether it has spread to nearby lymph nodes, and if it has metastasized to other parts of the body. The stages are:
- Stage I: Tumors are only in the peritoneum and are limited.
- Stage II: Tumors have grown and spread but have not invaded the lymph nodes.
- Stage III: Tumors have spread outside the peritoneum or invaded the lymph nodes.
- Stage IV: This stage often describes metastatic cancer, where tumors have spread to distant organs.
Treatment Options
Surgery
Surgery is often a primary treatment for peritoneal mesothelioma. The main surgical procedure is called cytoreductive surgery. This surgery aims to remove as much of the tumor as possible. Sometimes, this is followed by a heated chemotherapy treatment directly in the abdomen, known as HIPEC. This combination can help patients live longer.
Chemotherapy
Chemotherapy uses drugs to kill cancer cells. For peritoneal mesothelioma, it can be given in two ways: systemically or directly into the abdomen. Systemic chemotherapy travels through the bloodstream to reach cancer cells all over the body. Combination chemotherapy is often more effective than using a single drug.
Palliative Care and Supportive Treatments
Palliative care focuses on relieving symptoms and improving quality of life. This can include procedures like paracentesis, which drains fluid from the abdomen to reduce discomfort. Palliative care is especially important for patients who cannot undergo surgery or are in the later stages of the disease.
Prognosis and Survival Rates
Factors Affecting Prognosis
The prognosis for peritoneal mesothelioma is generally poor due to the aggressive nature of the disease. However, it is often better than the outlook for pleural mesothelioma. Several factors influence each patient’s prognosis:
- Age and health
- Gender
- Stage of the cancer at diagnosis
- Treatments chosen
- Concerning radiological features on CT
Survival Statistics
For peritoneal mesothelioma, the median survival time without disease progression is about 13.9 months. The five-year survival rates by stage are:
- Stage I – 87%
- Stage II – 53%
- Stage III – 29%
The 1-year survival rate of peritoneal mesothelioma is around 50%, similar to pleural mesothelioma. These rates decrease for 2-year, 3-year, and further.
Improving Survival Rates
Early diagnosis is key to improving prognosis. Aggressive, early treatments can increase the time patients live without visible cancer and improve their quality of life. The best survival rates are seen in patients who undergo cytoreductive surgery plus HIPEC. In a study, nearly three-quarters of patients who received this treatment lived longer than five years. Working with a team experienced in mesothelioma can also be very helpful.
Living with Peritoneal Mesothelioma
Managing Symptoms
Living with peritoneal mesothelioma involves managing a range of symptoms. Common symptoms include abdominal pain, swelling, and digestive issues. Patients may also experience fatigue and weight loss. It’s important to work closely with healthcare providers to develop a symptom management plan. This plan might include medications, dietary changes, and physical therapy.
Emotional and Psychological Support
A diagnosis of peritoneal mesothelioma can be emotionally challenging. Patients and their families often benefit from counseling and support groups. These resources provide a space to share experiences and coping strategies. Emotional support is crucial for maintaining mental health and well-being during treatment.
Resources for Patients and Families
There are many resources available to help patients and their families navigate life with peritoneal mesothelioma. These include:
- Support groups: Both in-person and online groups can offer community and understanding.
- Financial assistance: Programs and organizations can help with the costs of treatment and care.
- Educational materials: Information about the disease, treatment options, and living with cancer can empower patients and families.
It’s important to remember that peritoneal mesothelioma affects not just the patient but also their loved ones. Utilizing available resources can make a significant difference in managing the disease and improving quality of life.