Diagnostic and Treatment Approach for Suspected Peritoneal Carcinomatosis
For suspected peritoneal carcinomatosis, histopathological assessment is essential for diagnosis, followed by platinum-based chemotherapy for females with serous histologic type (similar to FIGO III ovarian cancer treatment), while cytoreductive surgery with HIPEC should be considered for selected patients with good performance status and limited disease burden. 1
Diagnostic Workup
Initial Assessment
- Thorough physical examination (including head/neck, rectal, pelvic, and breast examination)
- Basic blood and biochemistry tests
- Urinalysis and fecal occult blood test
- CT scan of thorax, abdomen, and pelvis (mandatory) 2
- Additional mammography in females 2
- FDG-PET/CT for single-site/oligometastatic cases 2
Histopathological Evaluation
Tissue biopsy with immunohistochemistry is crucial to categorize the carcinoma into:
- Well/moderately differentiated adenocarcinoma
- Poorly differentiated carcinoma
- Squamous cell carcinoma
- Undifferentiated neoplasm
- Carcinoma with neuroendocrine differentiation 2
Important Immunohistochemical Tests
- PSA in male patients
- Estrogen/progesterone receptors in females with axillary node metastases
- CK7 and CK20 to help identify possible primary site 1
- Additional molecular testing (NGS) may be performed routinely 2
Pitfall Alert: Up to 36% of peritoneal carcinomatosis cases with unknown primary may be occult appendiceal adenocarcinomas. Careful examination of the appendix during exploratory laparotomy is essential to avoid misdiagnosis. 3
Treatment Approach
For Female Patients with Peritoneal Carcinomatosis
- First-line treatment: Platinum-based chemotherapy similar to FIGO III ovarian cancer 2, 1
- Consider cytoreductive surgery (CRS) with optimal surgical debulking 1
- Evaluate for HIPEC eligibility based on:
- Good general health status
- Limited intraperitoneal tumor dissemination (PCI < 20)
- Limited small bowel involvement
- No extra-abdominal metastases 1
For Other Presentations
- Poorly differentiated carcinoma with predominantly nodal disease: Platinum-based combination chemotherapy 2, 1
- Poorly differentiated neuroendocrine carcinomas: Platinum plus etoposide combination 1
- Liver, bone, or multiple-site metastases of adenocarcinoma: Low-toxicity palliative chemotherapy or best supportive care 2, 1
Prognostic Factors and Risk Assessment
Positive Prognostic Factors
- Complete cytoreduction (R0 resection) 4, 5
- Small volume of ascites 4
- Perioperative intraperitoneal chemotherapy 4
- Second-look cytoreduction 4
Negative Prognostic Factors
- Poor ECOG performance status
- Male sex
- Higher number of metastatically involved organs
- Presence of liver metastases
- Adenocarcinoma histology
- Elevated alkaline phosphatase and LDH 2
Response Evaluation and Follow-up
- Evaluate treatment response after 2-3 chemotherapy cycles using appropriate imaging 2, 1
- No evidence supports routine follow-up of asymptomatic patients 2, 1
- Perform specific examinations as clinically indicated
Important Note: Long-term survival is possible with aggressive multimodal treatment. Studies show median survival of 21.8 months with CRS and HIPEC, with 5-year survival rates of approximately 19% 5, highlighting the importance of appropriate patient selection and treatment optimization.