Malignant peritoneal neoplasm is a serious condition that affects the thin lining of the abdomen, and its treatment requires a carefully planned approach that balances managing symptoms, controlling disease progression, and maintaining quality of life. Treatment decisions depend on where the cancer started, how far it has spread, and the overall health of the patient.

Understanding Treatment Goals for Peritoneal Cancer

When someone is diagnosed with a malignant peritoneal neoplasm, the primary goal of treatment is to control the cancer’s spread and improve the patient’s well-being. This type of cancer can either start in the peritoneum itself—the thin, protective membrane lining the abdominal cavity and covering internal organs—or it can spread there from other organs such as the ovaries, colon, stomach, or appendix.^[1][2]

Treatment approaches vary widely depending on whether the cancer is classified as primary peritoneal cancer, which originates in the peritoneum, or secondary peritoneal cancer, which has traveled from another organ. Both situations require expert medical teams that include surgical oncologists, medical oncologists, and sometimes gynecologic oncologists, all working together to create the most effective treatment plan.^[3][12]

Because symptoms often do not appear until the disease is advanced, many people are diagnosed at later stages. This timing makes treatment more complex, but modern medicine offers multiple strategies that can extend survival, reduce discomfort, and in some cases, even aim for a cure. The approach is highly individualized, taking into account the stage of the disease, the location and extent of tumor spread, the patient’s age and general health, and their personal preferences.^[4][9]

Standard Treatment Approaches

The foundation of treating malignant peritoneal neoplasm typically involves a combination of surgery and chemotherapy. For patients whose cancer has not spread beyond the abdominal cavity and who are otherwise healthy enough to undergo major surgery, cytoreductive surgery is often recommended. This procedure aims to remove all visible tumor tissue from the peritoneum and affected organs. Surgeons may need to remove portions of the peritoneum, parts of the intestines, or other affected tissues to achieve the goal of eliminating as much cancer as possible.^[12][14]

Cytoreductive surgery is a lengthy and complex operation, typically lasting six to nine hours. The procedure requires a highly experienced surgical team and specialized facilities. Recovery can take time, with most patients staying in the hospital for seven to fourteen days after the operation. The success of this surgery depends heavily on how much tumor can be removed—the more complete the removal, the better the potential outcome.^[14][21]

Immediately following cytoreductive surgery, many patients receive a treatment called hyperthermic intraperitoneal chemotherapy, or HIPEC. This innovative approach involves circulating heated chemotherapy solution—warmed to about 107 degrees Fahrenheit—directly into the abdominal cavity for approximately 90 minutes during surgery. The heat enhances the effectiveness of the chemotherapy drugs, allowing them to penetrate deeper into any remaining cancer cells that might be too small to see or remove surgically.^[12][14]

The chemotherapy drugs most commonly used in HIPEC procedures include cisplatin, mitomycin, and doxorubicin. Each of these medications works by damaging the DNA of cancer cells, preventing them from growing and dividing. The choice of which drug to use depends on the type of primary cancer and the patient’s overall health status.^[12][13]

For patients with primary peritoneal cancer, standard chemotherapy regimens typically combine a platinum-based drug—such as cisplatin or carboplatin—with a taxane drug like paclitaxel. This combination has been shown to be effective against the type of cancer cells found in peritoneal tumors. These medications are usually given through an intravenous line over several treatment cycles, with each cycle spaced a few weeks apart to allow the body to recover between treatments.^[12]

The duration of chemotherapy treatment varies depending on how well the cancer responds and how the patient tolerates the medications. Some patients receive chemotherapy for several months, with regular monitoring through blood tests and imaging scans to assess effectiveness. The goal is to shrink tumors, prevent cancer spread, and control symptoms while minimizing side effects.^[1]

Side effects from chemotherapy can include nausea, vomiting, fatigue, hair loss, numbness or tingling in the hands and feet (called peripheral neuropathy), and increased risk of infections due to lowered white blood cell counts. Medical teams provide supportive medications to help manage these side effects and monitor patients closely throughout treatment. Not everyone experiences all side effects, and their severity varies from person to person.^[12]

Another standard treatment option is targeted therapy, which uses drugs designed to attack specific abnormalities in cancer cells. For patients with certain genetic changes—particularly mutations in the BRCA1 or BRCA2 genes—a medication called olaparib may be recommended as maintenance therapy. Olaparib is a type of drug known as a PARP inhibitor, which works by blocking an enzyme that cancer cells need to repair their damaged DNA. This approach can help prevent cancer from returning or progressing after initial treatment.^[12]

In situations where surgery is not possible because the cancer is too widespread or the patient is not healthy enough for a major operation, systemic chemotherapy alone may be used as a palliative treatment. The goal in these cases is to slow disease progression, manage symptoms like abdominal swelling and pain, and improve quality of life. Different combinations of chemotherapy drugs may be tried based on how the cancer responds and what side effects develop.^[12][19]

For patients with malignant peritoneal mesothelioma—a specific type of peritoneal cancer that originates in the mesothelial cells of the peritoneum—the standard chemotherapy regimen combines cisplatin with pemetrexed. This combination has shown benefit in managing this rare form of the disease. Other drug combinations that may be used include cisplatin with paclitaxel, or regimens containing mitomycin, doxorubicin, and irinotecan.^[12][13]

Innovative Treatments in Clinical Trials

Beyond standard treatments, researchers around the world are actively studying new approaches to treating malignant peritoneal neoplasm through clinical trials. These trials test promising therapies that may eventually become standard options if they prove safe and effective. Participating in a clinical trial can give patients access to cutting-edge treatments that are not yet widely available.^[12]

One of the most exciting areas of research involves immunotherapy, which harnesses the body’s own immune system to fight cancer. These treatments work by helping immune cells recognize and attack cancer cells that would otherwise go undetected. Several types of immunotherapy drugs are being tested in peritoneal cancer patients, including immune checkpoint inhibitors such as pembrolizumab. These medications block proteins that prevent immune cells from attacking tumors, essentially releasing the brakes on the immune system.^[12]

In 2017, the United States Food and Drug Administration granted accelerated approval for pembrolizumab to treat certain patients with solid tumors, including mesothelioma, that have specific genetic characteristics and have not responded to other treatments. While most clinical trials of immune checkpoint inhibitors have focused on pleural mesothelioma (cancer in the chest cavity), researchers are now exploring whether these drugs can benefit patients with peritoneal mesothelioma as well. Early results are encouraging, though more research is needed to understand which patients are most likely to benefit.^[12]

Another promising area of investigation involves adding immunotherapy agents directly into the abdominal cavity during or after surgery. Researchers are studying whether combining heated chemotherapy with immune-stimulating substances like interleukins or interferons can enhance the body’s cancer-fighting response. These substances naturally occur in the body and help regulate immune function, but delivering them directly to the tumor site in higher concentrations may boost their effectiveness.^[12]

Scientists are also exploring whether targeting specific molecular pathways involved in cancer growth can lead to new treatment options. Research has identified that certain enzymes and signaling molecules play important roles in peritoneal mesothelioma development. For example, studies have found that an enzyme pathway called phosphatidylinositol-3-kinase, or PI3K, may be involved in the disease. This discovery has led to clinical trials testing PI3K inhibitors—drugs that block this pathway—to see if they can slow cancer growth.^[12]

Some clinical trials are investigating whether circulating tumor DNA (ctDNA) tests can help guide treatment decisions. These blood tests look for tiny fragments of DNA released by cancer cells into the bloodstream. By analyzing this genetic material, doctors may be able to detect cancer that doesn’t show up on imaging scans, monitor how well treatment is working, and identify when cancer returns earlier than traditional methods would allow. This approach is still being refined but represents a potential breakthrough in personalized cancer care.^[9][19]

Clinical trials are conducted in phases to ensure safety and effectiveness. Phase I trials primarily focus on determining safe dosing and identifying side effects in a small number of patients. Phase II trials expand to more participants and assess whether the treatment shows evidence of working against the cancer. Phase III trials compare the new treatment directly against current standard treatments to determine if the experimental approach offers advantages in survival, quality of life, or reduced side effects.^[3]

Many clinical trials for peritoneal cancer are available at specialized cancer centers in the United States, Europe, and other regions. Eligibility for specific trials depends on factors such as the type and stage of cancer, previous treatments received, overall health status, and sometimes the presence of specific genetic mutations. Patients interested in clinical trials should discuss options with their oncology team, who can help identify appropriate studies and explain the potential benefits and risks of participation.

Most Common Treatment Methods

• Cytoreductive Surgery (CRS)
  • Surgical removal of all visible tumor tissue from the peritoneum and affected organs in the abdominal cavity
  • Performed by specialized surgical oncologists in centers experienced with peritoneal cancer
  • Operation typically lasts six to nine hours with hospital stay of seven to fourteen days
  • Success depends on achieving complete or near-complete removal of visible tumors
• Hyperthermic Intraperitoneal Chemotherapy (HIPEC)
  • Heated chemotherapy solution circulated directly in the abdominal cavity for about 90 minutes during surgery
  • Temperature maintained at approximately 107 degrees Fahrenheit to enhance drug penetration
  • Uses drugs such as cisplatin, mitomycin, or doxorubicin
  • Targets microscopic cancer cells remaining after surgical removal of visible tumors
• Systemic Chemotherapy
  • Platinum-based drugs (cisplatin or carboplatin) combined with taxane drugs (paclitaxel)
  • Administered intravenously over multiple treatment cycles spaced several weeks apart
  • For peritoneal mesothelioma: cisplatin plus pemetrexed combination is standard
  • Used before surgery, after surgery, or as primary treatment when surgery is not possible
• Targeted Therapy
  • Olaparib (PARP inhibitor) for patients with BRCA1 or BRCA2 gene mutations
  • Works by blocking enzymes that cancer cells need to repair DNA damage
  • Used as maintenance therapy to prevent cancer recurrence or progression
  • Requires genetic testing to identify patients who will benefit
• Immunotherapy
  • Pembrolizumab and other immune checkpoint inhibitors being studied in clinical trials
  • Helps immune system recognize and attack cancer cells
  • FDA-approved for certain patients with unresectable or recurrent disease with specific genetic features
  • Research exploring combination with intraperitoneal delivery of interleukins and interferons