Peritoneal mesothelioma is a cancer found in the peritoneum, a thin membrane surrounding the abdomen. Peritoneal mesothelioma is the second most common form of the disease, accounting for about 15 – 20% of all diagnoses. The prognosis is generally poor, though more favorable than other forms of the disease.
Peritoneal mesothelioma is extremely rare, with about 500 diagnoses each year. As with all forms of mesothelioma, asbestos exposure is the primary cause. On average, peritoneal mesothelioma patients face a prognosis of six to twelve months, but newer treatments like hyperthermic intraperitoneal chemotherapy have improved survival rates in recent years.
What Is the Prognosis for Peritoneal Mesothelioma?
While the prognosis for all forms of mesothelioma is poor, the life expectancy for peritoneal mesothelioma cancer is better than other types of malignant mesothelioma. The median survival period for abdominal mesothelioma is one year, though more patients are surviving five years or longer with advancements in treatment.
Several factors can influence an individual patient’s prognosis, including:
While epithelioid cells are most commonly associated with mesothelioma, many peritoneal mesothelioma patients are diagnosed with the more rare sarcomatoid cell type. Sarcomatoid mesothelioma can metastisize quickly and doesn't respond well to treatment. Peritoneal mesothelioma patients with this cell type have an average survival of 4.6 months.
Epithelioid mesothelioma is slower to metastasize and easier to treat. Peritoneal mesothelioma patients with this cell type have a median life expectancy of 54 months. Biphasic mesothelioma, a mixture of epithelioid and sarcomatoid cells, is extremely rare in peritoneal mesothelioma patients. There is not enough available data on this specific subtype to determine average survival.
Patients with any cell type who undergo cytoreductive surgery with HIPEC have significantly better survival rates, with recent studies finding that at least 50% of malignant peritoneal mesothelioma patients survive five or more years.
Other studies have suggested even better survival times with the treatment, with one study noting a median survival of 92 months.
|1 year after diagnosis||92%|
|3 years after diagnosis||74%|
|5 years after diagnosis||65%|
|10 years after diagnosis||39%|
Peritoneal Mesothelioma Symptoms
The symptoms of peritoneal mesothelioma can take decades to appear after inhalation or ingestion of asbestos fibers. The fibers become lodged in the peritoneum, the lining of the abdomen, which leads to irritation and scar tissue. With time, the damaged cells can develop into tumors and cause noticeable symptoms.
For most patients, early symptoms will typically develop in the abdomen or gastrointestinal system. Patients may also experience systemic symptoms, like weight loss, which can further complicate diagnosis.
- Abdominal pain
- Abdominal swelling
- Anorexia / weight loss
- Ascites (fluid in the peritoneal cavity)
Less Common Symptoms
- Night sweats
- Hypercoagulability (blood clotting)
- Fever with no known origin
- Intestinal obstruction
- Inflammatory lesions
How Is Peritoneal Mesothelioma Diagnosed?
Because the symptoms of malignant peritoneal mesothelioma are often similar to those of other diseases, diagnosis can be difficult. A peritoneal mesothelioma diagnosis will start with imaging tests, like CT scans and x-rays, and blood tests to rule out more common diseases and other forms of cancer, like adenocarcinoma and ovarian cancer.
The most important step is the biopsy, which is currently the only way to confirm a peritoneal mesothelioma diagnosis. A doctor will take a fluid or tissue sample for analysis to confirm the cancer, as well as identify cell type and how the mesothelioma may progress.
This process is also important in differentiating rare subtypes of abdominal mesothelioma, like papillary and omental mesothelioma. Papillary mesothelioma develops in the peritoneum, but is often benign and can be surgically removed. Omental mesothelioma is more rare, developing in the omentum, a layer of the abdominal membrane that covers the intestines and stomach, and has a shorter prognosis than peritoneal mesothelioma.
Peritoneal Mesothelioma Stages
As part of the mesothelioma diagnosis process, the doctor will also determine the stage of the cancer. Although there is no formal staging system for peritoneal mesothelioma, doctors may try to identify how advanced the disease is using relevant criteria, like if the cancer has spread to the lymph nodes or other organs.
In some cases, doctors may also rely on a tool called the Peritoneal Cancer Index (PCI), developed for abdominal cancers. With this method, the abdominal region is split into 13 distinct sections and scored with 0 – 3 based on the presence and size of tumors. The 13 sections are then totaled for an overall PCI score, with 39 being the highest. Doctors have suggested peritoneal mesothelioma stages equivalent to the scores, with a higher PCI score indicating a more advanced stage of abdominal mesothelioma.
Peritoneal Mesothelioma Specialists
Finding a qualified mesothelioma specialist is one of the most important decisions someone diagnosed with peritoneal mesothelioma can make. Many of the best doctors work in dedicated cancer clinics across the country. Some of those doctors also conduct clinical trials to study new therapies and methods of treating and diagnosing mesothelioma.
Peritoneal Mesothelioma Treatment
Peritoneal mesothelioma is often treated with a multimodal approach, combining conventional treatments like surgery, chemotherapy and radiation therapy. Though systemic chemotherapy and radiation therapy have shown minimal success, with many clinical trials showing a median survival of one year, researchers continue to test new combinations and have found success with specific applications of chemotherapy.
Hyperthermic intraperitoneal chemotherapy (HIPEC), a heated chemotherapy wash applied to the abdomen, and Pressurized intraPeritoneal aerosol chemotherapy (PIPAC), chemotherapy applied through a pressurized form, have both shown success in clinical trials in extending life expectancy. HIPEC combined with surgery has helped at least 50% of mesothelioma patients live five years or longer. PIPAC is still in its early phases, but has so far enabled a median life expectancy of nearly 27 months.
Treatments like chemotherapy may also be applied palliatively for patients with advanced stage peritoneal mesothelioma. For instance, surgeries like paracentesis may be applied to remove buildup of fluid and relieve symptoms, improving the patient’s quality of life.
Emerging treatment options, like immunotherapy, have also shown promise in treating all forms of malignant mesothelioma. One of the most important advancements in treatment for peritoneal mesothelioma, however, has been the combination of cytoreductive surgery and HIPEC.
Hyperthermic Intraperitoneal Chemotherapy (HIPEC)
Researchers have noted the improvements in peritoneal mesothelioma survival rates are largely due to the combination of debulking surgery with HIPEC. Treatment starts with surgery that removes visible tumors and tissues that have been damaged by mesothelioma cells. Next, the heated chemotherapy wash is applied throughout the abdominal cavity to kill any remaining cancer cells. The heated intraperitoneal chemotherapy is applied at 104°F – 109°F and consists of a stronger dosage than systemic chemotherapy.
Since HIPEC is a more specialized treatment, it is currently only available at select cancer centers, like the Baylor College of Medicine and the University of Texas MD Anderson Cancer Center. Patients should also be aware of treatment costs as they make treatment decisions. Recent estimates show that surgery with HIPEC can average nearly $40,000.
Despite the expense, numerous clinical trials have shown the effectiveness of the treatment. Clinical trials have found survival times ranging from 53 to 92 months, with data suggesting upwards of 65% of patients are now surviving five years or longer. As research continues around HIPEC and other treatments, doctors hope to see survival rates continue to improve.
Author: Linda Molinari
Editor in Chief, Mesothelioma Cancer AllianceRead about Linda
Reviewer: Annette Charlevois
Patient Support CoordinatorRead about Annette
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