What is the best management approach for Pseudomyxoma peritonei?

Management of Pseudomyxoma Peritonei

Complete cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is the gold standard treatment for pseudomyxoma peritonei when complete cytoreduction is achievable. 1

Preoperative Assessment and Patient Selection

Imaging and staging are critical before proceeding with definitive treatment:

• CT scan of the chest, abdomen, and pelvis is the imaging modality of choice to evaluate disease extent and determine resectability 1
• Diagnostic laparoscopy should be considered to directly assess the feasibility of complete cytoreduction, particularly in patients where imaging is equivocal 1
• Patients must have no distant extraperitoneal metastases as pseudomyxoma peritonei typically remains confined to the peritoneal cavity 2
• Good performance status is essential given the extensive nature of the surgical intervention 3, 4

Surgical Management: The Cornerstone of Treatment

The surgical approach must be aggressive and comprehensive:

• All involved omentum must be removed to achieve optimal cytoreduction 1
• Appendectomy should be performed in all cases as the appendix is the most common primary site of mucinous tumors causing pseudomyxoma peritonei 1
• Complete cytoreductive surgery aims to remove all macroscopic tumor, with residual disease not exceeding 2mm (CC0-CC1 cytoreduction) 3, 4
• The extent of peritoneal involvement should be documented using the Peritoneal Cancer Index (PCI), though even patients with extensive disease (PCI ≥21) can achieve acceptable outcomes with complete cytoreduction 3

Intraperitoneal Chemotherapy: Essential Adjunct

Following complete cytoreduction, intraperitoneal chemotherapy eliminates microscopic residual disease:

• Patients with low-volume residual disease after surgical cytoreduction should receive intraperitoneal therapy 1
• HIPEC using mitomycin C is the most commonly employed regimen, administered intraoperatively for 90 minutes 5, 6
• Oxaliplatin-based HIPEC is an alternative that has demonstrated excellent long-term outcomes with 5-year overall survival of 80% and disease-free survival of 68.5% 4
• Early postoperative intraperitoneal chemotherapy (EPIC) using mitomycin C and 5-fluorouracil is equally efficacious to HIPEC, with comparable 10-year overall survival of 69% 3

The choice between HIPEC and EPIC appears equivalent in efficacy, so institutional expertise should guide selection 3.

Adjuvant Systemic Therapy

Depending on histological grading, patients should receive adjuvant systemic chemotherapy:

• 5-fluorouracil and leucovorin therapy is administered based on pathological findings 5
• This is particularly important for patients with higher-grade histology (peritoneal mucinous carcinomatosis) 3

Prognostic Factors and Expected Outcomes

Understanding prognostic factors helps set realistic expectations:

• Histopathological differentiation is the most important prognostic factor, with disseminated peritoneal adenomucinosis having the best prognosis 3, 4
• Female gender is associated with improved overall survival 3
• Elevated CA19-9 levels and higher pathological grade significantly impact disease-free survival 4
• 10-year overall survival of 69% and disease-free survival of 47% can be achieved with complete CRS and intraperitoneal chemotherapy 3
• 3-year actuarial survival of 81% has been reported with aggressive cytoreduction and HIPEC 5

Even patients with aggressive histology and extensive intraperitoneal tumor growth can achieve acceptable survival with complete cytoreduction 3.

Perioperative Risks and Complications

This aggressive approach carries significant morbidity that must be discussed:

• Postoperative mortality ranges from 4-7.6% in specialized centers 5, 4
• Major morbidity occurs in 18-67.6% of patients, correlating with peritoneal index, pathological grade, and CA19-9 levels 5, 4
• Bone marrow suppression from mitomycin C toxicity occurs in approximately 48% of patients 5
• Complications are significantly higher with extensive peritoneal disease (higher PCI scores) 4

Critical Management Principles

Several key principles determine success:

• Treatment should only be performed in specialized centers with expertise in cytoreductive surgery and intraperitoneal chemotherapy 6
• Complete cytoreduction is mandatory - if complete cytoreduction cannot be achieved, the survival benefit is substantially diminished 4, 6
• Recurrence occurs in approximately 40% of patients at 10 years, requiring long-term surveillance 3
• Some patients require repeated surgeries over extended periods (potentially over a decade) for recurrent disease 2

When Surgery Is Not Feasible

For patients who cannot undergo complete cytoreduction:

• Palliative debulking may provide symptomatic relief but does not improve survival 6
• These patients should be referred to specialized centers for evaluation rather than undergoing incomplete procedures at non-specialized institutions 6