Malignant peritoneal mesothelioma is a rare and aggressive cancer that forms in the tissue lining the abdominal cavity. Though there is no cure, advances in surgical techniques combined with specialized chemotherapy have transformed what was once a universally fatal diagnosis into a condition where some patients now live for many years with careful treatment and comprehensive care.

Understanding Treatment Goals for Peritoneal Mesothelioma

When doctors diagnose malignant peritoneal mesothelioma, the first conversation with patients often centers on what treatment can realistically achieve. This cancer develops in the peritoneum, which is the thin membrane that lines the inside of the abdomen and covers organs like the liver, stomach, and intestines. Because this disease spreads throughout the abdominal cavity rather than moving to distant parts of the body, treatment strategies focus on controlling the cancer where it grows.^[2]

The main goals of treating peritoneal mesothelioma include slowing down how fast the cancer spreads, reducing painful symptoms like abdominal swelling and discomfort, and extending survival as much as possible. Without any treatment, patients typically survive less than one year after diagnosis.^[2] However, modern treatment approaches have changed this outlook considerably, with some patients now living five years or longer when they receive aggressive combined therapy.^[13]

Treatment decisions depend heavily on several factors. Doctors consider how far the cancer has spread within the abdomen, the patient’s overall physical fitness, whether they can tolerate major surgery, and the specific characteristics of their tumor cells. Younger patients with limited disease spread and good general health typically have more treatment options available.^[10]

Medical societies and cancer centers have developed standard approaches based on years of research and experience. At the same time, researchers continue exploring new therapies through clinical trials. These experimental treatments offer hope that future patients may have even better outcomes than what is possible today.^[9]

Standard Treatment Approaches

The most effective standard treatment for peritoneal mesothelioma combines two powerful approaches: extensive surgery to remove visible cancer tissue, followed immediately by heated chemotherapy delivered directly into the abdomen. This combination has become the preferred approach at major cancer centers worldwide.^[16]

Cytoreductive Surgery (CRS)

The surgical component is called cytoreductive surgery, sometimes referred to as debulking surgery. During this lengthy operation, surgeons work to remove all visible cancer tissue from the abdominal cavity. This may involve removing parts of the peritoneum itself, which can mean taking out sections of the abdominal lining along with any affected organs.^[12]

In some cases, surgeons need to remove portions of the intestines, spleen, gallbladder, or other organs if cancer has spread to these areas. The operation is extremely complex and can take many hours to complete. Only patients who are physically strong enough to withstand such extensive surgery are candidates for this approach.^[13]

The goal is not necessarily to remove every single cancer cell, which is often impossible, but to reduce the amount of cancer tissue to the smallest possible burden. This gives the chemotherapy that follows a better chance of destroying remaining cancer cells.^[16]

Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

Immediately after cytoreductive surgery, while the patient is still in the operating room, doctors perform hyperthermic intraperitoneal chemotherapy, or HIPEC. This involves filling the abdominal cavity with heated chemotherapy solution. The fluid is warmed to temperatures between 41 and 43 degrees Celsius (about 106 to 109 degrees Fahrenheit).^[13]

The heat serves two purposes. First, it directly damages cancer cells, making them more vulnerable to the chemotherapy drugs. Second, the warmth helps the chemotherapy penetrate deeper into any remaining tissue. The heated solution stays in the abdomen for 60 to 90 minutes while medical staff gently rock the patient’s body to ensure the drug reaches all areas.^[16]

Common chemotherapy drugs used in HIPEC include cisplatin, often combined with doxorubicin or mitomycin C. These medications work by damaging the DNA inside cancer cells, preventing them from dividing and growing.^[16]

Systemic Chemotherapy

For patients who cannot undergo surgery because their cancer is too widespread or their health is too fragile, doctors may recommend systemic chemotherapy. These are drugs given through a vein that travel throughout the entire body via the bloodstream.^[10]

The standard systemic chemotherapy combination for peritoneal mesothelioma includes pemetrexed and cisplatin. Pemetrexed works by blocking enzymes that cancer cells need to make DNA and RNA, essentially starving them of building blocks they need to divide. Cisplatin damages the DNA structure itself. Together, these drugs can slow cancer growth and reduce symptoms.^[10]

Another option is gemcitabine combined with cisplatin. Gemcitabine interferes with DNA replication in a different way than pemetrexed, offering an alternative for patients whose cancer doesn’t respond to the first combination.^[10]

Patients typically receive systemic chemotherapy in cycles, with treatment given over a few days followed by a rest period of several weeks. This allows the body to recover from side effects before the next cycle begins. Treatment may continue for several months.^[12]

Potential Side Effects

The combined surgery and HIPEC approach carries significant risks because of the extent of the operation. Patients may experience infection, bleeding, blood clots, or problems with wound healing. The heated chemotherapy can cause temporary damage to the intestines, leading to digestive problems that may take weeks or months to resolve.^[10]

Recovery from cytoreductive surgery with HIPEC typically requires a hospital stay of one to two weeks, sometimes longer if complications develop. Full recovery at home may take several additional months as the body heals from the extensive surgery.

Systemic chemotherapy causes different side effects. Pemetrexed and cisplatin commonly lead to nausea, vomiting, fatigue, and reduced blood cell counts that can increase infection risk. Many patients experience temporary hair thinning, though not always complete hair loss. Cisplatin can damage nerves, causing numbness and tingling in the hands and feet, and may harm kidney function if patients don’t stay well-hydrated.^[10]

Palliative and Supportive Care

Not every patient can receive aggressive surgery or chemotherapy. For those with advanced disease or poor overall health, palliative care focuses on relieving symptoms and maintaining quality of life. This is not about giving up, but about prioritizing comfort and managing the disease’s effects on daily living.^[12]

One common palliative procedure is paracentesis, which drains fluid that accumulates in the abdomen. Peritoneal mesothelioma often causes ascites, a buildup of fluid that makes the belly swell and feel tight and uncomfortable. Doctors can insert a needle through the abdominal wall to drain this fluid, providing immediate relief. Some patients need this procedure repeated every few weeks.^[14]

Pain management is another crucial aspect of palliative care. Specialists can prescribe medications ranging from simple pain relievers to stronger opioid drugs, adjusting doses to keep patients comfortable while minimizing side effects. Some patients benefit from nerve blocks, where doctors inject medication near specific nerves to reduce pain signals.^[12]

Treatment in Clinical Trials

Because standard treatments cannot cure peritoneal mesothelioma and work better for some patients than others, researchers are actively testing new approaches through clinical trials. These studies offer access to promising therapies that are not yet widely available.^[9]

Immunotherapy

One of the most exciting areas of research involves immunotherapy, which harnesses the body’s own immune system to fight cancer. Cancer cells have clever ways of hiding from immune cells or turning off immune responses. Immunotherapy drugs work by removing these barriers, allowing the immune system to recognize and attack cancer cells more effectively.^[10]

Checkpoint inhibitors are a type of immunotherapy that has shown promise in treating peritoneal mesothelioma. These drugs target proteins on immune cells or cancer cells that act like brakes on the immune response. Two important checkpoint proteins are called PD-1 and PD-L1. When cancer cells display PD-L1 on their surface and it connects with PD-1 on immune cells, it tells the immune system to leave the cancer alone.^[10]

Drugs that block this interaction include pembrolizumab and nivolumab, which target PD-1, and atezolizumab and durvalumab, which target PD-L1. Clinical trials are testing these medications both alone and in combination with standard chemotherapy. Some trials specifically enroll patients whose tumor cells test positive for PD-L1 expression, as these patients may be most likely to benefit.^[10]

Researchers are also investigating whether combining immunotherapy with cytoreductive surgery and HIPEC might produce better results than any single approach alone. This is a high priority area for future research.^[9]

Novel Chemotherapy Approaches

Scientists continue developing new ways to deliver chemotherapy more effectively to cancer cells while reducing harm to healthy tissue. Some clinical trials test intraperitoneal chemotherapy given after surgery, but at normal body temperature rather than heated. This approach, sometimes called early postoperative intraperitoneal chemotherapy or long-term normothermic intraperitoneal chemotherapy, may extend the benefits of HIPEC with potentially fewer side effects.^[16]

One regimen involves administering cisplatin, ifosfamide, doxorubicin, and paclitaxel through a catheter placed directly into the abdominal cavity during recovery from surgery. The chemotherapy bathes the peritoneal surface where cancer cells tend to recur. Some research suggests this approach, combined with surgery and HIPEC, may help patients achieve five-year survival rates of 70 percent or higher.^[16]

Clinical Trial Phases

Clinical trials progress through distinct phases, each designed to answer specific questions about a new treatment. Phase I trials focus primarily on safety. Researchers carefully increase the dose of a new drug to find the highest amount patients can tolerate without severe side effects. These early trials typically enroll small numbers of patients who have already tried standard treatments without success.^[9]

Phase II trials test whether a treatment actually works against the cancer. Researchers look for signs that tumors shrink or stop growing, that symptoms improve, or that patients live longer. These studies enroll more patients than Phase I trials but still represent a relatively small group, often 20 to 50 people.

Phase III trials compare a new treatment directly against the current standard of care. These large studies may enroll hundreds of patients, with some receiving the new treatment and others getting standard therapy. Only if the new treatment proves better in Phase III trials will it likely become approved for widespread use.^[9]

Trial Locations and Eligibility

Clinical trials for peritoneal mesothelioma take place at major cancer centers throughout the United States, Europe, and other regions. In the United States, the National Cancer Institute and several comprehensive cancer centers actively conduct research on this disease. European countries including France, Italy, the Netherlands, and the United Kingdom also run important trials.^[9]

Eligibility requirements vary by study, but generally include confirmation of the peritoneal mesothelioma diagnosis through biopsy, acceptable overall health status, and adequate organ function to tolerate the experimental treatment. Many trials exclude patients whose cancer has spread beyond the abdominal cavity or who have severe other medical conditions. Age limits may apply to some studies.^[9]

Most common treatment methods

• Cytoreductive surgery with HIPEC
  • Extensive surgery to remove all visible cancer tissue from the abdominal cavity, including portions of the peritoneal lining and potentially affected organs
  • Immediately followed by heated chemotherapy solution circulated throughout the abdomen for 60 to 90 minutes
  • Chemotherapy drugs commonly include cisplatin, doxorubicin, or mitomycin C heated to 41-43 degrees Celsius
  • Requires patients to be physically strong enough for major surgery lasting many hours
  • Hospital stay typically lasts one to two weeks with several months of home recovery
  • Considered the most effective standard treatment, potentially extending survival to five years or more in selected patients
• Systemic chemotherapy
  • Intravenous drugs that travel throughout the body via the bloodstream
  • Standard combination includes pemetrexed and cisplatin given in cycles over several months
  • Alternative combination uses gemcitabine with cisplatin
  • Offered to patients who cannot undergo surgery due to widespread disease or poor health
  • Side effects include nausea, fatigue, reduced blood counts, and potential nerve damage
  • Modest response rates but can help slow cancer growth and reduce symptoms
• Immunotherapy (in clinical trials)
  • Checkpoint inhibitor drugs targeting PD-1 or PD-L1 proteins to enhance immune system recognition of cancer cells
  • Specific drugs being studied include pembrolizumab, nivolumab, atezolizumab, and durvalumab
  • Tested alone or in combination with standard chemotherapy
  • Patients whose tumors express PD-L1 may be most likely to benefit
  • Research exploring combination with surgery and HIPEC is a high priority
• Intraperitoneal chemotherapy
  • Chemotherapy delivered directly into the abdominal cavity through a catheter
  • Can be given at normal body temperature after surgery (normothermic approach)
  • Drugs may include cisplatin, ifosfamide, doxorubicin, and paclitaxel
  • Designed to target cancer cells on the peritoneal surface where recurrence commonly occurs
  • Some research suggests this approach combined with surgery and HIPEC may achieve 70 percent five-year survival
• Palliative care
  • Focuses on symptom relief and quality of life for patients with advanced disease
  • Paracentesis to drain accumulated abdominal fluid (ascites) providing immediate comfort
  • Pain management with medications ranging from simple analgesics to opioids
  • Nerve blocks to reduce pain signals in specific areas
  • Nutritional support and management of digestive symptoms
  • Coordination by specialized palliative care teams including doctors, nurses, and other specialists