What is Peritoneal Mesothelioma?
Malignant peritoneal mesothelioma is a rare and aggressive cancer that forms in the abdomen. It is also known as abdominal mesothelioma or mesothelioma of the stomach.
The only proven cause of peritoneal mesothelioma is exposure to asbestos. Asbestos fibers are inhaled or ingested and will become lodged in the abdomen
There are around 300 to 500 cases of peritoneal mesothelioma diagnosed each year in the USA.
The prognosis for this type of mesothelioma is very poor with most patients only surviving 1-2 years. A new type of multimodal treatment, cytoreductive surgery and HIPEC, a heated chemotherapy wash, has been successful in extending patient life expectancy and some have lived more than 5 years after a peritoneal mesothelioma diagnosis.
What Causes Peritoneal Mesothelioma?
As with all types of mesothelioma cancer, abdominal mesothelioma is caused by exposure to asbestos fibers. These fibers are ingested or inhaled and can even travel through the bloodstream to reach the abdomen and cause the cancer years after exposure.
This delay in discovering the cancer is known as the latency period. For most, the latency period for peritoneal mesothelioma is between 20 to 60 years. The asbestos fibers and cancer can be dormant for decades before affecting the patient.
How Peritoneal Mesothelioma Develops
Like other asbestos-related diseases, peritoneal mesothelioma will develop over a long period of time and may even take decades to show up. The asbestos fibers will cause inflammation, irritation and damage the DNA of the cells it affects.
The damaged DNA will lead to abnormal cell growth. These errors cause tumors to form and grow uncontrollably. In many cases these tumors will spread to other parts of the body over time.
Based on current research, there are only two ways scientists believe asbestos can get to your stomach and they are through raw ingestion and through your lymphatic system passing the fibers through all of your organs.
How Asbestos Fibers Reach Your Stomach
The lymphatic system is a network of connected tissue and organs that help fight disease. Some experts believe asbestos fibers initially enter through the lungs. The fibers are then transported through the lymphatic system to the abdominal cavity, where they can become stuck in the peritoneum.
An individual may inhale or swallow airborne asbestos fibers. The fibers may pass through the bloodstream or the digestive system and get lodged in the lining of the abdomen.
Symptoms of Peritoneal Mesothelioma
The most common symptoms for peritoneal mesothelioma are bloating, pain and tenderness around the abdomen along with having digestion issues such as diarrhea or constipation. Due to the latency of the disease, many symptoms for abdominal mesothelioma will not develop for many years or until the cancer reaches a more advanced stage.
Peritoneal Mesothelioma Symptoms
- Abdominal pain
- Abdominal swelling (ascites)
- Night Sweats
- Nausea and vomiting
- Unexplained weight loss
- Loss of appetite
- Bowel or urinary problems
If you were exposed to asbestos by using a known asbestos product or by using asbestos at work and you feel any of the symptoms, you should speak with your doctor and discuss your history. Your doctor may recommend yearly mesothelioma screenings, such as an imaging test, to monitor for any new or worsening symptoms.
How is Peritoneal Mesothelioma Diagnosed?
A diagnosis will typically begin with a variety of tests to rule out other illnesses and types of cancer, including imaging scans and blood tests. These tests can help avoid misdiagnosis. Peritoneal mesothelioma is most commonly mistaken for other abdominal cancers, irritable bowel syndrome (IBS) or ovarian cancer.
Currently, a biopsy or tissue sample is the only definitive method to diagnose mesothelioma. The doctor will perform a laparoscopy or laparotomy to take a sample of the tissue from the abdominal lining.
Once the biopsy is taken, a pathologist will analyze the sample tissue under a microscope to determine if the cells are cancerous. A pathologist can further categorize the cell type and the severity of the abdominal mesothelioma’s progression.
Diagnosing Rare Forms of Peritoneal Mesothelioma
There are also two rare forms of peritoneal mesothelioma.
Rare Forms of Peritoneal Mesothelioma
- This type is also known as well-differentiated papillary mesothelioma (WDPM).
- This form most often develops in the peritoneum.
- Papillary mesothelioma is often benign and can be surgically removed.
- Prognosis is favorable, with some documentation of patients surviving 12 years or longer.
- This form develops in the omentum, a layer of the abdominal membrane that covers organs like the intestines and stomach.
- This rare type may be a result of peritoneal mesothelioma spreading (metastasis).
- There is no standard treatment, but case reports document chemotherapy as an option.
- Prognosis may be poor.
Peritoneal Mesothelioma Staging
Because of its rarity, there is no set staging system for peritoneal mesothelioma. However, doctors may still be able to identify how advanced the disease is and its progression for an individual case.
Doctors may use the general mesothelioma staging system to determine the cancer’s progression. Commonly, in stage 1 and stage 2 the tumor is localized. In later stages, tumors are more likely to have spread to nearby organs and lymph nodes.
Peritoneal cancers also have another system that helps identify the severity of tumor progression and helps determine what treatments a patient is eligible for.
What Is the Peritoneal Cancer Index?
The Peritoneal Cancer Index (PCI) is a notable tool used by oncologists for several decades. The PCI works by segmenting the abdominal region into 13 distinct sections.
Oncologists will then “score” the region based on the number and size of the tumors present through imaging scans. This is known as a lesion score.
The overall PCI is calculated by adding the scores for each region together, with the highest PCI being 39. The regional scores and overall PCI will help oncologists determine how far the cancer has advanced.
Peritoneal Cancer Index
- 0: No tumors
- 1: Up to 0.5 cm
- 2: Up to 5 cm
- 3: Larger than 5 cm or multiple tumors
- 1-10 : Stage 1
- 11-20: Stage 2
- 21-30: Stage 3
- 31-39: Stage 4
In general, a higher score indicates a more advanced stage. A patient’s stage of peritoneal mesothelioma is an important factor in determining their prognosis.
Peritoneal Mesothelioma Prognosis
Peritoneal mesothelioma life expectancy has been improving. Compared to other forms of mesothelioma, peritoneal mesothelioma has the most favorable prognosis. Median survival for peritoneal mesothelioma is about 31 months.
Prognosis may vary based on several factors:
- Location: The origin of the cancer may determine how it will impact the rest of the body.
- Stage: Generally, lower stages experience better prognosis.
- Cell type: The three main cell types are epithelioid, sarcomatoid and biphasic. Epithelioid has the best prognosis.
Peritoneal Mesothelioma Prognosis Based on Cell Type
- Epithelioid mesothelioma: 16 months
- Sarcomatoid mesothelioma: 4 months
- Biphasic mesothelioma: 9 months
These factors also impact a patient’s treatment plan. Treatment is the best way for patients to improve their prognosis.
Thanks to advancements in treatment, peritoneal mesothelioma patients have started to see an improved life expectancy. Studies indicate more than 50% of patients treated with surgery and heated chemotherapy survive 5 years or longer.
Peritoneal Mesothelioma Survival Rate
Peritoneal mesothelioma survival rates have continuously improved over the past decade. Breakthroughs in treatment and improved diagnostic technology have allowed patients to improve life expectancy.
Peritoneal Mesothelioma Survival Rates by Stage
- Stage 1: 92%
- Stage 2: 86%
- Stage 3: 84%
- Stage 4: 63%
- Stage 1: 85%
- Stage 2: 65%
- Stage 3: 57%
- Stage 4: 40%
- Stage 1: 85%
- Stage 2: 52%
- Stage 3: 48%
- Stage 4: 30%
*This data is according to stages based on the Peritoneal Cancer Index (PCI)
Peritoneal Mesothelioma Specialists
Peritoneal mesothelioma doctors have experience treating this rare form of cancer. A peritoneal specialist will work with patients to create a treatment plan for their unique case.
Many peritoneal specialists are connected to top hospitals and cancer centers. These facilities have the most up-to-date technology and allow patients to get top quality treatment.
Surgical oncologist at University of Maryland Marlene and Stewart Greenebaum Cancer Center
Gastrointestinal surgical oncologist at Washington Cancer Institute
Surgical oncologist UPMC Hillman Cancer Center
Peritoneal Mesothelioma Treatment
Peritoneal mesothelioma specialists often rely on three standard treatments for any type of mesothelioma: surgery, chemotherapy and radiation. Most often, two or more treatments are combined to have the best effect on a patient’s prognosis. This is called multimodal treatment.
These treatments may be administered with therapeutic or palliative intent. When administered with therapeutic intent, treatments like surgery aim to potentially extend survival. Palliative treatments help improve quality of life and relieve a patient’s symptoms.
One common palliative surgery is called paracentesis. It may be administered for patients experiencing peritoneal effusion, or excess abdominal fluid. The operation removes the fluid build up in the peritoneum to relieve pressure in the abdomen and alleviate symptoms.
If peritoneal mesothelioma patients do not respond to common treatments, they may enroll in a clinical trial. Promising experimental treatments that may extend survival are tested in clinical trials. Each clinical trial has its own eligibility criteria, so patients should talk to their doctor about their options.
Cytoreductive Surgery and HIPEC
Many studies have shown the positive effects of treating abdominal mesothelioma with cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). HIPEC is a heated chemotherapy wash that circulates through the abdominal cavity immediately after surgery.
With the surgery, doctors aim to remove all visible tumors in the abdominal cavity. Doctors then administer HIPEC throughout the abdomen to kill any remaining cancer cells.
Some studies have found this combination therapy successful in extending patient life expectancy. In one study, 45% of patients survived 10 years or longer.
Although HIPEC can’t cure peritoneal mesothelioma, it may be one of the most effective treatment options for eligible patients.
Is Peritoneal Mesothelioma Curable?
There is no cure for peritoneal mesothelioma. Seeking treatment is the best way for mesothelioma patients to improve their prognosis.
Thanks to the work of doctors and researchers, mesothelioma treatment has come a long way. They continue to develop new treatments and treatment combinations to further improve mesothelioma survival.