What is the management of pseudomyxoma peritonei?

Management of Pseudomyxoma Peritonei

The optimal treatment for pseudomyxoma peritonei (PMP) is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for patients with limited disease burden (Peritoneal Cancer Index ≤10) after initial systemic chemotherapy and multidisciplinary evaluation. 1

Diagnosis and Staging

• Diagnostic laparoscopy with peritoneal washing cytology is essential for accurate staging
• Determination of Peritoneal Cancer Index (PCI) is crucial to quantify disease burden
• CT imaging is the primary modality for initial assessment and follow-up
• Patients may present with:
  • Abdominal distention
  • Abdominal pain
  • Loss of appetite
  • Shortness of breath due to extensive ascites 2

Patient Selection Criteria

Optimal candidates for CRS+HIPEC include:

• Limited disease burden (PCI ≤10)
• Good performance status
• No extra-abdominal metastases
• Likelihood of achieving complete cytoreduction 1

Treatment Algorithm

1. Initial Approach:

   • Administer systemic chemotherapy for at least 3 months
   • Re-stage to assess response

2. For Resectable Disease:

   • Complete cytoreductive surgery (CRS) to remove all visible disease
   • HIPEC administered during the same procedure
   • Completeness of cytoreduction is the most significant factor affecting survival 1

3. For Unresectable/High-Grade Disease:

   • Palliative debulking surgery to relieve symptoms
   • Combination chemotherapy with neo-angiogenesis inhibitors (e.g., trifluridine/tipiracil with bevacizumab) 3
   • Consider whole abdominopelvic radiotherapy (WAPRT) using intensity-modulated arc therapy for intestinal obstruction 4

Surgical Considerations

The surgical approach typically involves:

• Bilateral parietal and diaphragmatic peritonectomies
• Right hemicolectomy (as appendix is common primary site)
• Radical greater omentectomy with splenectomy
• Cholecystectomy and liver capsulectomy
• Pelvic peritonectomy with or without rectosigmoid resection
• Bilateral salpingo-oophorectomy with hysterectomy in females 5

Treatment Outcomes

• Complete cytoreduction (CCR-0) is associated with median survival of 42.9 months
• Minimal residual disease (≤2.5mm) is associated with median survival of 17.4 months
• Gross residual disease is associated with median survival of only 5 months 1
• Treatment-related mortality with CRS+HIPEC is approximately 8% 1

Follow-up Protocol

• Clinical visits every 3 months for the first 3 years
• Then every 6 months for 2 more years
• CT scans of chest and abdomen every 6-12 months for high-risk patients 1

Special Considerations

• PMP has a unique feature of slow disease progression, which may be asymptomatic until advanced stages
• Even extensive disease with high PCI may still be amenable to complete excision and potential cure 5
• In cases where complete tumor removal is not feasible, maximum tumor debulking can still result in long-term survival
• Patients should be referred to specialized centers with expertise in treating peritoneal surface malignancies 6
• The role of HIPEC remains somewhat controversial, with some studies questioning its added benefit over CRS alone 1

Recurrent Disease Management

• Selected patients may benefit from repeated CRS with or without HIPEC
• However, each repeated debulking procedure becomes less effective with increased morbidity
• For patients with intestinal obstruction due to recurrent disease, WAPRT may provide palliative relief 4

By following this comprehensive approach to PMP management, patients can achieve the best possible outcomes for this rare but potentially curable peritoneal malignancy.