Peritoneal Mesothelioma & What to Expect

Peritoneal mesothelioma is the second-most common form of mesothelioma. It accounts for approximately 10 to 15 percent of all cases.

This cancer is caused by exposure to asbestos. People who worked with asbestos products throughout their career are most at risk.

The latency period associated with peritoneal mesothelioma is shorter than for the pleural form of the disease. Peritoneal mesothelioma latency is 20-30 years, compared to 30-40 years for pleural mesothelioma.

The prognosis for most patients is poor. Most patients are diagnosed with the diffuse form of the disease, which is very aggressive. The median survival for untreated patients is around six months.

However, selected patients can be treated with surgery and heated chemotherapy. The median survival of such patients ranges between 30 and 92 months.

Exposure to asbestos is the primary cause of peritoneal mesothelioma. Asbestos is a mineral that was used in industrial, commercial and domestic products.

Most people who get sick from exposure worked with asbestos products for many years.

Ascites, a buildup of fluid in the peritoneal lining, is present in 90 percent of peritoneal patients.

Abdominal pain, bloating and changes in bowel habits are the most common symptoms that cause patients to visit the doctor.

A variety of tests are used to diagnose mesothelioma including imaging scans, ascites fluid tests and tumor biopsies. An official diagnosis usually requires a laparoscopic biopsy.

Biopsies provide tumor samples that are examined with a microscope to identify the exact type of mesothelioma cancer cells present. More than 80 percent of peritoneal tumors are made up of epithelial cells. These cells respond better to mesothelioma treatment than the other cancer cell types such as sarcomatoid and biphasic cells.

Unlike pleural mesothelioma, there is no official staging system for the peritoneal form of the disease.

Doctors have identified three stages based on studies of peritoneal patients undergoing surgery. A fourth stage hasn’t been clearly identified, but it is generally accepted that the fourth stage involves local spread of tumors throughout the abdomen.

Treatment for peritoneal mesothelioma involves surgery and chemotherapy.

Surgery is more effective for peritoneal mesothelioma than for the pleural form of the disease. In practice, this means that peritoneal patients who undergo surgery tend to live longer than pleural patients who undergo surgery.

Conversely, radiation therapy is less effective. Radiation is rarely used on peritoneal patients.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy, commonly called HIPEC or heated chemotherapy, is the most effective treatment for this cancer. The median survival after treatment ranges between 30 and 92 months.

A minor surgical procedure, called paracentesis, is used on patients with ascites. This procedure is often used to relieve symptoms of abdominal swelling and pain associated with fluid buildup.

The most effective chemotherapy drugs for peritoneal mesothelioma include Alimta (pemetrexed), cisplatin, carboplatin and gemcitabine.

Experimental therapies are under investigation in clinical trials. Examples include immunotherapy and gene therapy.

A number of peritoneal patients try complementary therapies to ease cancer symptoms and reduce treatment side effects. Examples include nutritional therapy, acupuncture, tai chi and relaxation therapies.

The prognosis for the majority of peritoneal mesothelioma patients is poor. Average survival is around six months in untreated patients.

Selected patients can be treated with cytoreductive surgery and heated chemotherapy. Survival among these patients is between 30 and 92 months.

Systemic chemotherapy is the next-best option for patients who are diagnosed too late for surgery.

A 2017 study of peritoneal patients reported the outcomes of chemotherapy with cisplatin and Alimta delivered systemically (throughout the body). About 45.8 percent of participants responded to the drugs, and their tumors were controlled for an average of 11 months. Overall survival was 15.8 months.

However, patients in this study with a form of peritoneal mesothelioma known as “wet-type” had an average survival of 40.9 months. Numerous studies have reported longer survival among patients with this type of the disease regardless of the treatment they receive.

Untreated peritoneal mesothelioma is associated with an average survival of eight months.

A 2017 study that included 53 peritoneal mesothelioma patients reported that 21.5 percent of them received no cancer treatment. It also reported that 51.8 percent underwent at least one surgical procedure.

The best way for patients to improve their prognosis with peritoneal mesothelioma is to work with a mesothelioma specialist. Additionally, patients can consider clinical trials to access new treatment options.