Peritoneal Mesothelioma

What Is Malignant Peritoneal Mesothelioma?

Malignant peritoneal mesothelioma is a rare and aggressive cancer that forms in the abdomen. It’s also known as abdominal mesothelioma or mesothelioma of the stomach.

The primary proven cause of malignant peritoneal mesothelioma is asbestos exposure. Asbestos fibers are inhaled or ingested and become lodged in the abdomen.

Peritoneal Mesothelioma Facts

About 300 to 500 peritoneal mesothelioma cases are diagnosed each year in the U.S. The incidence is distributed equally among women and men. This contrasts with pleural mesothelioma, which develops in the lungs and is far more common in men.

An even rarer form of peritoneal mesothelioma cancer develops in a layer of the abdominal membrane, the omentum, that covers the stomach and other organs.

“The first thing I like to tell [peritoneal mesothelioma patients] is that they certainly do have options. With good treatment that we use now, that median survival could actually be several years.”

Dr. W. Charles Conway

Peritoneal mesothelioma specialist

What Are the Symptoms of Peritoneal Mesothelioma Cancer?

Presenting symptoms of peritoneal mesothelioma include bloating, pain or tenderness around the abdomen, and digestion issues such as constipation or diarrhea. Symptoms of peritoneal mesothelioma do not develop in many patients until the cancer reaches an advanced stage.

These symptoms tend to mimic many other abdominal disorders. An accurate diagnosis often requires a mesothelioma specialist and a biopsy sample. 

Anyone who was exposed to asbestos should discuss their history with their doctor. Mesothelioma screenings, such as regular imaging tests, may be recommended. Your doctor can monitor any new or worsening symptoms.

What Causes Peritoneal Mesothelioma?

The main cause of malignant peritoneal mesothelioma is exposure to asbestos fibers. Current research suggests that asbestos fibers may travel through the bloodstream to reach the abdomen, causing cancer after years of inflammation.

Process of Peritoneal Mesothelioma Development

Like other asbestos-related diseases, peritoneal mesothelioma develops over a long period of time. The trapped asbestos fibers cause inflammation and irritation, damaging and degrading DNA. 

Damaged DNA can lead to abnormal and unregulated cell growth. These errors cause tumors to form, and the tumors can grow uncontrollably and spread to other areas of the body.

Research on malignant peritoneal mesothelioma is still ongoing. This disease is rare and connected to toxic exposure to industrial pollutants, including asbestos. Other potential causes of the disease may include exposure to abdominal radiation and fibrous minerals besides asbestos, such as erionite.

How Is Peritoneal Mesothelioma Diagnosed?

While every diagnostic test serves a contributing purpose to the diagnostic process, the only way to confirm a malignant peritoneal mesothelioma diagnosis is with a biopsy. In addition to a biopsy, imaging scans and blood tests are typically used in the abdominal mesothelioma diagnosis process.

Biopsies are samples of tumor tissue that doctors examine under a microscope in a lab. Medical professionals, called pathologists, perform tests on the biopsy sample to reveal the kinds of cancerous cells within the tumors. They then summarize the results in a pathology report.

Patients will also receive a thorough examination of their medical history, occupational history and overall physical condition.

Diagnosing Peritoneal Mesothelioma Cell Types

The pathology report contains information about which cellular subtype of peritoneal mesothelioma you have. Diagnosing the cell type is important because it helps doctors determine which therapies may work best for you.

Common Cell Types

Epithelioid peritoneal mesothelioma can grow in four different patterns: Papillary, tubular, diffuse and deciduous. Papillary is the most common and often appears alongside the others.

Pure sarcomatoid tumors are uncommon in malignant peritoneal mesothelioma. Specialists have only diagnosed about 30 cases of this variant since 2006. Sarcomatoid cells usually occur alongside epithelioid cells to form the biphasic subtype.

Additionally, omental mesothelioma is a rare variant that occurs in the omentum, a part of the peritoneum surrounding the stomach and other abdominal organs. The omentum is a layer of fatty tissue that plays a role in immune function and metabolism.

Misdiagnosing Peritoneal Mesothelioma

Because this cancer is rare, doctors lacking experience with the disease often misdiagnose abdominal mesothelioma patients with more common illnesses that share similar symptoms. Peritoneal mesothelioma misdiagnosis can delay proper treatment.

If you have a history of asbestos exposure, the best way to ensure an accurate diagnosis is to schedule an appointment with a mesothelioma specialist. Doctors who specialize in peritoneal mesothelioma have the knowledge and tools needed to make a precise diagnosis.

“Getting an accurate diagnosis was not easy. A fibroid tumor was what they said I had and that it would go away on its own. I asked the doctors, and they all told me, ‘You will be fine.’ It took a specialist to get the breakthrough I needed.”

Tamron Little

Peritoneal mesothelioma survivor

Watch: Peritoneal mesothelioma survivor Tamron Little talks to The Mesothelioma Center about her initial misdiagnosis and the importance of finding a specialist.

Stages of Peritoneal Mesothelioma

While there is no official staging system for peritoneal mesothelioma, a research report in 2020 suggested that oncologists adapt the TNM system, widely used for pleural mesothelioma, into three stages for peritoneal.

3 Stages of Peritoneal Mesothelioma

There is no precise fourth stage in the adapted TNM system for malignant peritoneal mesothelioma. Many doctors consider stage 4 to involve extensive tumors that have spread to distant sites throughout the body.

Peritoneal Cancer Index

The Peritoneal Cancer Index is a diagnostic tool doctors use to assess tumor location and spread in the abdomen. It helps them determine the approximate mesothelioma stage and appropriate treatments.

This index divides the abdomen into 13 parts. Doctors assign a number (one to three) to each area based upon the most sizable tumor in that area. The Peritoneal Cancer Index score is the sum of the individual scores from the 13 regions. A patient’s maximum score is 39 (13 times three).

Lower index scores mean the patient may qualify for surgery. Index scores above 20 indicate cancer has spread too far and the patient likely won’t respond well to surgery.

Peritoneal Mesothelioma Treatment Options

The most effective peritoneal mesothelioma treatment option is cytoreductive surgery with heated chemotherapy, known as hyperthermic intraperitoneal chemotherapy, or HIPEC.

More than 60% of patients are ineligible for surgery with heated chemotherapy, however, because of the procedure’s intensity. Because cytoreductive surgery can take several hours and may involve removing large portions of the intestines or whole organs, chemotherapy alone is the most used treatment.

Chemotherapy

Patients who don’t qualify for surgery with heated chemotherapy can receive systemic chemotherapy alone. Some patients receive only intraperitoneal chemotherapy. 

Chemotherapy drugs can shrink peritoneal mesothelioma tumors and slow the growth and spread of cancer. Chemotherapy drugs that are effective against peritoneal mesothelioma include pemetrexed, cisplatin, carboplatin and gemcitabine.

U.S. Navy pilot and peritoneal mesothelioma survivor Jim Madaris decided to seek out the HIPEC procedure after his diagnosis in 2013. The surgery took 14 hours and removed his gallbladder, spleen and parts of his intestine. Madaris’ life was extended by four years, allowing him to find joy in the little things and see his youngest child graduate high school.

“I’m fortunate. I’ve lasted four times longer than my first doctor expected. Even if something happens tomorrow, we’re still calling it a victory.”

Jim Madaris

Diagnosed with peritoneal mesothelioma

Palliative Treatment Options

In addition to anti-cancer treatments, many peritoneal patients receive palliative care to control symptoms and improve quality of life. For example, a paracentesis procedure may be recommended to certain peritoneal patients to drain excess fluid from the abdomen.

A palliative care specialist prescribes medications to control pain and side effects. They may refer patients to physical or occupational therapy or recommend complementary therapies.

Top Peritoneal Doctors

Peritoneal Mesothelioma Life Expectancy and Prognosis

The prognosis for peritoneal mesothelioma is generally poor for patients who don’t qualify for surgery. Those who qualify for multimodal treatment, however, may improve their prognosis by several years.

Peritoneal mesothelioma life expectancy is approximately 12 months for patients who receive chemotherapy alone. The median survival of peritoneal mesothelioma patients who do not undergo any treatment is six months.

However, the prognosis for surgical candidates is significantly better. Surgery and heated chemotherapy can improve peritoneal survival by several years. 

About half of peritoneal patients who undergo a combination of cytoreductive surgery with heated chemotherapy have a life expectancy of more than five years.

According to a 2020 study published in the American Journal of Surgical Pathology, women with malignant peritoneal mesothelioma tend to live longer than men. In the study, 77.8% of women treated with cytoreductive surgery and heated chemotherapy at MD Anderson Cancer Center in Houston survived longer than five years. 

When averaging short- and long-term survival, women live approximately 13 months on average, and men live roughly six months.

When averaging short- and long-term survival, women live approximately 13 months on average, and men live roughly six months.

Factors Affecting Prognosis

Patients with tumors containing epithelial cells have a longer life expectancy than patients with sarcomatoid or biphasic cells. Epithelial cells tend to respond better to treatments such as chemotherapy.

The tumor’s grade also impacts prognosis. Tumor grade indicates how quickly tumors are likely to grow and spread, based upon how abnormal the cells appear.

Chemotherapy Survival Rates

Systemic (whole-body) chemotherapy combined with cisplatin and pemetrexed has the following benefits:

Chemotherapy delivered directly to the peritoneum without surgery has a higher response rate of 47%. When combined with heated chemotherapy given during surgery, the response rate is 84.6%

Is There a Cure for Peritoneal Mesothelioma?

There is no cure for peritoneal mesothelioma or any other type of mesothelioma. However, peritoneal patients eligible for surgery and HIPEC typically live longer than five years.

Some patients may be eligible for repeat surgery with heated chemotherapy if a cancerous mesothelioma recurrence happens.

In 2017, Dr. Paul Sugarbaker reported improved survival among patients who received early post-operative chemotherapy and long-term chemotherapy after cytoreductive surgery with heated chemotherapy.

Of the 29 patients who had surgery with HIPEC, post-operative chemotherapy and long-term chemotherapy, 75% lived longer than five years. No patients in the study received intravenous or systemic chemotherapy.

Feelings of depression or loneliness are common among peritoneal mesothelioma patients. Support services such as counselors and support groups are available. Talking to a counselor or joining a support group can help improve quality of life.

The Mesothelioma Center, for example, hosts an online support group that connects mesothelioma patients and families with one another and offers professional guidance from facilitators. Dana Nolan, MS, LMHC, is a licensed counselor and serves as the moderator. Patient advocate and registered nurse Karen Selby is also available to answer medical questions.

Common Questions About Peritoneal Mesothelioma

What are the symptoms of peritoneal mesothelioma?

The symptoms of peritoneal mesothelioma include abdominal pain, abdominal swelling or distension, diarrhea or constipation, weight loss and fatigue. Other symptoms may develop as the disease progresses, such as fever and night sweats.

How fast does peritoneal mesothelioma spread?

Peritoneal mesothelioma spreads fairly quickly. Exact rates of spread vary individually and are affected by the cell type of the tumors. Patients who do not undergo treatment have a median survival of six months. This means peritoneal mesothelioma spreads significantly within half a year without treatment.

Is peritoneal mesothelioma curable?

Malignant peritoneal mesothelioma is incurable at all four stages. Clinical trials are searching for a cure by testing new treatments, including immunotherapy and multimodal therapy.

How long do peritoneal mesothelioma patients live?

Peritoneal mesothelioma patients have a life expectancy of about one year. However, survival is significantly better for patients who qualify for surgery with heated chemotherapy. Half of the patients who qualify for this procedure live at least five years.