National Institutes of Health Reports on Advances in Malignant Peritoneal Mesothelioma

A new article from the National Institutes of Health gives the latest advances in mesothelioma. CRS-HIPEC has offered improved survival for surgical candidates. But outcomes for inoperable malignant peritoneal mesothelioma remain poor.

Advancements in technology have provided new treatment approaches. The NIH reports new clinical trials are arising and are imperative.

The Numbers Behind Peritoneal Mesothelioma

Peritoneal mesothelioma is caused by exposure to asbestos. It is caused by the ingestion of asbestos fibers. Those microscopic asbestos fibers become embedded in the abdomen (peritoneum). After 20 to 50 years, these fibers can cause inflammation and mutations in the healthy mesothelial cells. These mutations can cause these cells to become cancerous thus, forming tumors in the peritoneum. Patients diagnosed with peritoneal mesothelioma may survive several or more years after diagnosis. There are some long-term survivors.

The team from the National Cancer Institute reports this cancer occurs in less than 1,000 people in the United States every year. Rates of this mesothelioma vary throughout the world and are highest in Australia and the United Kingdom. Diagnosis often occurs in people over the age of 65. But peritoneal mesothelioma has occurred in people much younger.

Computed tomography (CT) is the principal imaging choice used for diagnosis. While positron emission tomography (PET) can be used with CT, its value is not clear.

Malignant mesothelioma has three histological subtypes. They include epithelioid (56%), sarcomatoid (31%), and mixed/biphasic type (13%). Epithelioid peritoneal mesothelioma is considered the least aggressive subtype. It also has the most favorable prognosis in general.

Malignant peritoneal mesothelioma comprises 20% to 30% of all mesothelioma in developed countries. In the U.S. each year approximately 500 to 800 new cases of peritoneal mesothelioma are diagnosed.

Peritoneal patients are diagnosed at a younger age, with equal disease distribution between men and women, according to the article published in Digestive Medicine Research.

Surgical Treatment Options

At the time of diagnosis, Dr. Blakely reports the majority of patients have advanced disease. Without treatment, the median overall survival is at best 6 months.

In the past, mesothelioma was resistant to cytotoxic chemotherapy. But there have been advances in technology and improved understanding of tumor treatments. The standard of care for mesothelioma is cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC).

With advances in operative technique, CRS-HIPEC has shown encouraging five-year survival results.

Non-Surgical Treatment Options

On the other hand, outcomes for unresectable peritoneal mesothelioma remains grim, with a median survival of 1 year.

Patients with inoperable tumors can be offered several treatments. These include chemotherapy, immune checkpoint inhibitors, or investigational treatments.

The efficacy of systemic chemotherapy is poor. Peritoneal mesothelioma is associated with relative chemoresistance. A phase III clinical trial showed better survival in patients who received pemetrexed with cisplatin. The addition of bevacizumab also increases significant overall patient survival.

Of late, immune checkpoint inhibitors (ICI) have been an area of interest for second-line treatment. ICIs have shown effective in peritoneal mesothelioma. They have recently been approved for first-line treatment. But, the evidence for the efficacy of ICI has been limited.

Conclusion

Malignant peritoneal mesothelioma is a rare and lethal disease caused by asbestos.

The National Institutes of Health reports CRS-HIPEC remains the standard of care for mesothelioma disease. In 2022, several clinical trials are available for patients with peritoneal mesothelioma. Each clinical trial offers future advances in therapy and further understanding of this rare disease.

Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is the standard of care for patients.

Source

Gregory, Stephanie N., A. Leila Sarvestani, and Andrew M. Blakely. “Malignant peritoneal mesothelioma literature review: past, present, and future.” (2022). https://dx.doi.org/10.21037/dmr-22-19