Pseudomyxoma peritonei (PMP) is a rare and complex condition that requires specialized treatment approaches to manage effectively and improve patient outcomes. Understanding the available treatment options—from standard surgical procedures to innovative therapies being tested in clinical trials—can help patients and families navigate this challenging diagnosis with greater confidence and hope.

Managing a Rare and Complex Disease

When someone receives a diagnosis of pseudomyxoma peritonei, the path forward depends on many individual factors. The main goal of treatment is to remove as much of the mucin-producing cancer cells as possible from the abdominal cavity, control symptoms, and improve quality of life. Because PMP develops slowly and behaves differently from other cancers, treatment plans must be carefully tailored to each patient’s situation.^[1]

Treatment decisions are based on several important considerations: how far the disease has spread throughout the abdomen, the grade or aggressiveness of the cancer cells, the patient’s overall health and fitness for surgery, and whether vital organs can be preserved. In some cases, patients may be diagnosed early when the disease is small and slow-growing, while others discover PMP only after it has filled much of the abdominal cavity with mucin.^[3]

Medical teams caring for PMP patients typically include specialists from multiple disciplines—surgeons experienced in complex abdominal procedures, medical oncologists, pathologists, radiologists, and supportive care providers. This collaborative approach ensures that every aspect of the patient’s care is considered. Because PMP is so rare, affecting only 1 to 4 people per million each year, seeking care at a specialized center with experience treating this condition is highly recommended.^[2]

Standard Treatment Approaches

The cornerstone of pseudomyxoma peritonei treatment is a combined approach called cytoreductive surgery with hyperthermic intraperitoneal chemotherapy, commonly known as CRS with HIPEC. This has become the internationally recognized standard of care for patients who are suitable candidates for this intensive procedure.^[11]

Cytoreductive surgery aims to remove all visible disease from the abdominal cavity. During this operation, surgeons carefully remove the lining of the abdomen called the peritoneum, along with any tissues that have been affected by the mucin-producing cells. This may involve removing several organs or parts of organs. Commonly removed structures include the omentum (fatty tissue that hangs from the stomach), the spleen, gallbladder, appendix, and portions of the bowel. In women, the ovaries, uterus, and fallopian tubes are often removed as well.^[12]

The goal is to achieve what surgeons call a complete cytoreduction, meaning no visible tumor tissue remains at the end of the operation. This is a complex and lengthy procedure that can take 10 hours or more to complete. The success of the surgery depends greatly on the skill and experience of the surgical team, which is why treatment at specialized centers is so important.^[10]

Immediately following the removal of visible disease, heated chemotherapy is delivered directly into the abdominal cavity while the patient is still in the operating room. This is the HIPEC portion of treatment. The most commonly used chemotherapy drug is mitomycin C, though some centers may use other agents such as oxaliplatin.^[11]

The chemotherapy solution is heated to around 41-43 degrees Celsius (approximately 106-109 degrees Fahrenheit) and circulated throughout the abdomen for about 90 minutes. The heat helps the chemotherapy penetrate more deeply into any remaining microscopic cancer cells that couldn’t be seen and removed during surgery. After this treatment period, the solution is drained from the abdomen, and the surgical incisions are closed.^[14]

Following CRS with HIPEC, patients typically spend 1-2 days in an intensive care unit or high dependency unit where they can be closely monitored. Various tubes and drains will be in place—these may include a urinary catheter, an epidural for pain control (a small tube placed near the spine), a nasogastric tube (from the nose to the stomach to prevent nausea), abdominal drains to remove excess fluid, and intravenous lines for nutrition and medications. Most of these are temporary and will be removed as recovery progresses.^[11]

The hospital stay after this surgery is typically 2 to 3 weeks, though some patients may need longer depending on how their body responds to the treatment. Recovery continues at home and can take 6 months or more before patients feel fully active again and can return to work or normal activities. This is major surgery, and patience with the healing process is essential.^[12]

Some patients may experience complications after surgery. These can include infections, blood clots, problems with wound healing, bowel obstruction, or fistulas (abnormal connections between organs). If the spleen was removed, patients will need vaccinations to protect against certain infections and will need to take antibiotics for the rest of their life, as the spleen plays an important role in fighting infections. Blood transfusions may be needed if significant blood loss occurred during the operation.^[11]

Alternative Surgical Approaches

Not all patients are candidates for the complete CRS with HIPEC procedure. For those whose disease is too extensive or whose health is too fragile for this intensive surgery, debulking surgery may be an option. This approach removes as much of the mucin and tumor tissue as possible, even if complete removal isn’t achievable. While debulking doesn’t cure PMP, it can significantly improve quality of life by reducing abdominal swelling, relieving pressure on the bowel and other organs, and easing symptoms like pain and difficulty eating.^[1]

Some patients may need repeated debulking procedures over time as the disease progresses. While this ongoing surgical approach doesn’t offer the same potential for long-term disease control as complete cytoreduction with HIPEC, it can help patients live more comfortably with their condition for extended periods.^[9]

Watch and Wait

For patients diagnosed with very small, slow-growing PMP who are not experiencing symptoms, doctors may recommend a period of active monitoring called watch and wait or active surveillance. This approach involves regular checkups with blood tests and imaging scans to monitor the disease but delays treatment until it becomes necessary.^[11]

The watch and wait strategy can be emotionally difficult for patients who feel that “doing nothing” means allowing the disease to progress. However, this approach recognizes that PMP often grows very slowly and that early aggressive treatment isn’t always beneficial, especially if the disease is minimal and not causing problems. The medical team will carefully monitor for any signs that treatment should begin, such as increasing mucin production, symptom development, or evidence of more aggressive disease behavior.^[3]

Treatment Being Explored in Clinical Trials

Because pseudomyxoma peritonei is rare and standard treatment can be challenging, researchers are actively investigating new approaches to improve outcomes. Clinical trials offer patients access to promising therapies that are not yet widely available while helping scientists learn more about what works best for this unusual cancer.

Modifications to Intraperitoneal Chemotherapy

While HIPEC during surgery is the standard approach, researchers are studying different ways to deliver chemotherapy directly into the abdomen. One approach being investigated is early postoperative intraperitoneal chemotherapy, abbreviated as EPIC. With this technique, chemotherapy is administered through tubes left in the abdomen after surgery, continuing for several days after the operation rather than just during surgery. The goal is to expose any remaining cancer cells to chemotherapy for a longer period.^[15]

Another innovative delivery method being tested is pressurized intraperitoneal aerosol chemotherapy, or PIPAC. This technique converts liquid chemotherapy into a fine mist or aerosol that is sprayed into the abdominal cavity under pressure. The aerosol form may allow better penetration of the chemotherapy into tissue surfaces. PIPAC can potentially be performed through small incisions rather than requiring major open surgery, making it less invasive than traditional approaches.^[9]

Clinical trials are comparing these different chemotherapy delivery methods to determine which provides the best balance of effectiveness and tolerability. Some studies are also investigating different chemotherapy drugs or combinations of drugs for intraperitoneal use, beyond the standard mitomycin C. The choice of chemotherapy agent and delivery method may ultimately be tailored to individual patient characteristics and disease features.^[15]

Systemic Chemotherapy

Unlike intraperitoneal chemotherapy that is delivered directly into the abdomen, systemic chemotherapy is given through the bloodstream, typically by intravenous infusion. Traditional systemic chemotherapy has not been particularly effective for most cases of PMP, which is one reason why direct intraperitoneal treatment became the standard approach. However, researchers continue to study whether systemic chemotherapy might benefit certain patients.^[15]

Systemic chemotherapy might be considered for patients with high-grade or more aggressive forms of PMP, for those whose disease has returned after surgery, or for patients who cannot undergo surgery. Clinical trials are testing various systemic chemotherapy regimens, often using combinations of drugs commonly employed for colorectal cancer or other digestive system cancers. Some studies are examining whether giving systemic chemotherapy before surgery might shrink the disease and make surgical removal more successful.^[9]

The effectiveness and role of systemic chemotherapy in PMP treatment remains an area of active investigation, with ongoing research aimed at identifying which patients are most likely to benefit and what the optimal drug combinations and timing might be.

Novel Therapeutic Approaches

Scientists are exploring entirely new types of treatments that target specific molecular features of PMP cancer cells. One experimental approach involves using substances called BromAc, which is being investigated for its potential to affect the mucin-producing cancer cells. Research into such novel agents is still in early phases, but represents the kind of innovative thinking needed to improve treatment for this challenging disease.^[9]

Other areas of investigation include studying the genetic and molecular characteristics of PMP tumors to understand what drives their growth and mucin production. Research has identified that many PMP cases have mutations in genes such as KRAS and changes in the MUC2 gene, which is involved in mucin production. Understanding these molecular features may eventually lead to targeted therapies designed specifically for the abnormalities found in PMP cells.^[5]

Immunotherapy approaches, which harness the body’s immune system to fight cancer, are being studied in various peritoneal surface malignancies. While PMP has not traditionally been considered highly responsive to immunotherapy, ongoing research continues to explore whether certain patients or disease subtypes might benefit from these treatments.^[9]

Clinical Trial Participation

Clinical trials for PMP are conducted at specialized medical centers, often in multiple countries to gather enough patients with this rare condition. Trials typically proceed through phases: Phase I studies test the safety of new treatments and determine appropriate doses; Phase II studies examine whether treatments show promise of effectiveness; and Phase III studies compare new treatments against current standard approaches to determine if the new therapy is better.^[9]

Patients considering clinical trial participation should discuss the potential benefits and risks with their medical team. Eligibility for trials depends on many factors including the extent of disease, previous treatments received, overall health status, and specific characteristics of the cancer. While clinical trials offer access to potentially promising new therapies, they also involve uncertainties, as the treatments being tested have not yet proven superior to standard approaches.

Most Common Treatment Methods

• Cytoreductive Surgery (CRS)
  • Complete removal of all visible tumor tissue and mucin from the abdominal cavity
  • Removal of the peritoneal lining and affected organs or tissues
  • May include removal of omentum, spleen, gallbladder, appendix, portions of bowel, and reproductive organs
  • Goal is achieving complete cytoreduction with no visible disease remaining
  • Lengthy procedure that can take 10 or more hours to complete
• Hyperthermic Intraperitoneal Chemotherapy (HIPEC)
  • Heated chemotherapy delivered directly into the abdomen during surgery
  • Most commonly uses mitomycin C, sometimes oxaliplatin or other agents
  • Chemotherapy solution heated to approximately 41-43 degrees Celsius
  • Circulated throughout abdomen for about 90 minutes during operation
  • Aims to kill microscopic cancer cells that cannot be surgically removed
• Debulking Surgery
  • Removes as much mucin and tumor as possible when complete cytoreduction isn’t achievable
  • Performed when disease is too extensive or patient health doesn’t allow for complete CRS with HIPEC
  • Relieves symptoms by reducing abdominal pressure and improving organ function
  • May need to be repeated over time as disease progresses
  • Improves quality of life even when cure is not possible
• Early Postoperative Intraperitoneal Chemotherapy (EPIC)
  • Chemotherapy delivered through tubes into abdomen after surgery
  • Continues for several days following the operation
  • Being studied in clinical trials as addition or alternative to HIPEC
  • Provides extended exposure of remaining cells to chemotherapy
• Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC)
  • Chemotherapy converted to pressurized aerosol mist sprayed into abdomen
  • May allow better tissue penetration than liquid chemotherapy
  • Can be performed through small incisions rather than open surgery
  • Currently being investigated in clinical trials
  • Potentially less invasive alternative for some patients
• Systemic Chemotherapy
  • Chemotherapy drugs given through the bloodstream by intravenous infusion
  • Role in PMP treatment remains under investigation in clinical trials
  • May be considered for high-grade disease or recurrent PMP
  • Various drug combinations being studied, often similar to colorectal cancer regimens
  • Sometimes given before surgery to potentially shrink disease
• Watch and Wait (Active Surveillance)
  • Close monitoring with regular checkups, blood tests, and imaging scans
  • Delays treatment for small, slow-growing disease not causing symptoms
  • Treatment initiated when disease shows signs of progression or symptoms develop
  • Appropriate for carefully selected patients with minimal disease