Treatment for Pseudomyxoma Peritonei
The optimal treatment for pseudomyxoma peritonei is complete cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC), which offers the best chance for cure and long-term survival. 1, 2
Preoperative Assessment
Before proceeding to surgery, obtain the following:
- CT scan of chest, abdomen, and pelvis to evaluate disease extent and determine feasibility of complete cytoreduction 1
- Consider diagnostic laparoscopy to directly assess whether complete cytoreduction is achievable, particularly in cases where imaging suggests extensive disease 1
- Evaluate tumor markers (CEA, CA 19-9, CA-125), as elevations correlate with worse prognosis and increased recurrence rates 3
Surgical Approach: Cytoreductive Surgery (CRS)
Complete macroscopic tumor excision is the goal, as this provides the best outcomes even in extensive disease with high Peritoneal Carcinomatosis Index (PCI) 2. The procedure typically includes:
- Mandatory appendectomy in all cases, as the appendix is the likely primary site 1
- Complete omentectomy (removal of all involved omentum) 1
- Bilateral parietal and diaphragmatic peritonectomies 2
- Right hemicolectomy 2
- Radical greater omentectomy with splenectomy 2
- Cholecystectomy and liver capsulectomy 2
- Pelvic peritonectomy with or without rectosigmoid resection 2
- Bilateral salpingo-oophorectomy with hysterectomy in females 2
Total operating time is approximately 10 hours for extensive disease 2. Unlike other peritoneal malignancies, very extensive PMP with high PCI may still be amenable to complete excision and cure 2.
Intraperitoneal Chemotherapy
Patients with low-volume residual disease after surgical cytoreduction should receive intraperitoneal therapy 1. HIPEC is administered during the same operative session as CRS 2, 3.
Even when complete tumor removal is not feasible, maximum tumor debulking combined with HIPEC can result in long-term survival 2.
Expected Outcomes
Survival varies significantly by histologic grade:
- Low-grade disease: 5-year survival ranges from 62.5% to 100% 3
- High-grade disease: 5-year survival ranges from 0% to 65% 3
Treatment-related morbidity ranges from 12% to 67.6%, and mortality ranges from 0% to 9% 3.
Management of Recurrent Disease
Recurrence occurs in approximately 32% of patients after complete cytoreduction, with 95.9% occurring within 5 years and 81.6% isolated to the peritoneal cavity 4.
For recurrent disease:
- Repeat CRS with or without HIPEC is the preferred approach for selected patients, offering 5-year overall survival of 80.3% compared to 44.8% with palliative management 4
- Repeat procedures have similar safety and efficacy to primary operations, with comparable perioperative morbidity and long-term survival 4
- Longer progression-free survival after primary treatment predicts better outcomes after treatment of recurrence 5
- Systemic chemotherapy alone for recurrence has poor outcomes, with all patients in one series dying of disease (median survival 14.8 months) 5
Avoid repeat curative surgery in patients over 65 years or those with high-grade carcinoma peritonei, as these are negative predictors of successful repeat intervention 4.
Key Clinical Pitfalls
- Do not rely solely on CT imaging: CT sensitivity for peritoneal metastases is only 28-51%, despite 97-99% specificity 6. Consider diagnostic laparoscopy when CT findings are equivocal.
- Do not attempt incomplete cytoreduction without HIPEC: While maximum debulking can provide benefit, the combination of complete CRS with HIPEC provides superior outcomes 2, 3.
- Do not dismiss extensive disease as unresectable: PMP has unique biology with slow progression, and even high PCI may be amenable to complete excision 2.