What is the recommended treatment plan for peritoneal adenocarcinoma?

Treatment of Peritoneal Adenocarcinoma

For patients with peritoneal adenocarcinoma, the recommended treatment approach is cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) for selected patients with limited disease burden (Peritoneal Cancer Index [PCI] ≤10), after initial systemic chemotherapy and multidisciplinary evaluation. 1, 2

Patient Selection and Initial Approach

Initial Assessment

• Diagnostic laparoscopy with peritoneal washing cytology is recommended for accurate staging 1
• CT scans of chest and abdomen for baseline assessment and to rule out extra-abdominal disease 2
• Determination of peritoneal cancer index (PCI) to quantify disease burden 1

Selection Criteria for Aggressive Treatment

• Limited peritoneal disease (PCI ≤10) 1
• Good performance status 2
• No extra-abdominal metastases 2
• Likelihood of complete cytoreduction 1

Treatment Algorithm

Step 1: Initial Systemic Therapy

• Administer systemic chemotherapy for a minimum of 3 months 1
• Re-staging after initial chemotherapy to assess response 1

Step 2: Multidisciplinary Evaluation

• For patients with low PCI (≤10), stable or improved disease, and no extraperitoneal metastases, proceed to multidisciplinary discussion 1
• Evaluate likelihood of complete cytoreduction 1

Step 3: Definitive Treatment

• For patients likely to achieve complete cytoreduction:

  • Gastrectomy (if gastric primary) with cytoreductive surgery and HIPEC 1
  • Complete removal of all visible nodules/plaques is essential 2

• For patients unlikely to achieve complete cytoreduction:

  • Continue systemic therapy 1
  • Consider clinical trial participation 1

• For patients with high PCI (>10) or disease progression:

  • Systemic therapy 1
  • Best supportive care 1
  • Clinical trial participation 1

Evidence for Treatment Approach

Outcomes with CRS and HIPEC

• Complete cytoreduction (CCR-0) is associated with median survival of 42.9 months 2
• Minimal residual disease (≤2.5mm) is associated with median survival of 17.4 months 2
• Gross residual disease has median survival of only 5 months 2

Clinical Trial Evidence

• The CYTO-CHIP study showed improved overall survival and recurrence-free survival with CRS+HIPEC compared to CRS alone for peritoneal metastases from gastric cancer 1
• A phase III trial demonstrated median survival of 11 months with CRS+HIPEC versus 6.5 months with surgery alone (p=0.046) 1
• However, the GASTRIPEC-I trial showed no significant difference in overall survival between CRS with and without HIPEC 1

Important Considerations

Treatment-Related Risks

• Surgical complications occur in approximately 38% of patients 3
• Treatment-related mortality is reported at 3-8% 2, 3
• Chemotherapy toxicity primarily manifests as leukocytopenia (52% of patients) 3

Origin-Specific Approaches

• For colorectal peritoneal metastases: CRS with HIPEC has shown benefit in selected cases 1, 2
• For gastric peritoneal metastases: Evidence is mixed, with some studies showing benefit and others showing no improvement in overall survival 1

Follow-up Recommendations

• Clinical visits every 3 months for the first 3 years, then every 6 months for 2 more years 1, 2
• CT scans of chest and abdomen every 6-12 months for high-risk patients 1, 2
• CEA testing for applicable cases 1

Pitfalls to Avoid

• Attempting CRS+HIPEC in patients with high PCI (>10), as outcomes are poor 1, 2
• Performing these procedures at inexperienced centers (should be done at specialized centers with expertise in peritoneal surface malignancies) 2
• Neglecting the importance of complete cytoreduction, which is the most significant factor affecting survival 2