What is carcinomatosis?

Carcinomatosis: Definition and Management

Carcinomatosis is defined as the widespread dissemination of cancer cells throughout a body cavity, most commonly the peritoneal cavity, representing advanced metastatic disease with significant implications for morbidity and mortality.

Definition and Pathophysiology

Carcinomatosis refers to the spread of tumor cells within a body cavity, with peritoneal carcinomatosis being the most common form. It represents a pattern of metastatic disease characterized by:

• Dissemination of cancer cells throughout the lining of a body cavity
• Most frequently affects the peritoneal cavity (peritoneal carcinomatosis)
• Can also occur in the pleural space or leptomeninges (leptomeningeal carcinomatosis)
• Represents advanced stage disease with significant impact on survival 1

Types of Carcinomatosis

Peritoneal Carcinomatosis

• Most common form, involving dissemination throughout the peritoneal cavity
• Second most common presentation of colon cancer distant metastasis 2
• Common in gastrointestinal cancers (colorectal, gastric) and gynecologic malignancies (ovarian) 2, 3
• Characterized by multiple tumor implants on peritoneal surfaces
• Often presents with ascites, abdominal distension, and bowel obstruction

Leptomeningeal Carcinomatosis

• Spread of tumor cells within the leptomeninges and subarachnoid space
• Occurs in approximately 10% of patients with metastatic cancer 4
• Most commonly from breast cancer, lung cancer, and melanoma
• Associated with brain metastases in 33-54% of breast cancer, 56-82% of lung cancer, and 87-96% of melanoma patients 4

Diagnostic Approach

Diagnosis of carcinomatosis requires a comprehensive evaluation:

• Imaging studies: CT scan of thorax, abdomen, and pelvis is mandatory; FDG-PET/CT recommended for evaluating disease extent 5
• Tissue biopsy with immunohistochemistry: Crucial for determining cancer type and origin 5
• Laboratory studies: Basic blood work, tumor markers (e.g., CA-125 for ovarian-like carcinomatosis)
• Additional imaging: Mammography in females, brain MRI if leptomeningeal disease is suspected 5

Treatment Options

Treatment depends on the primary tumor, extent of disease, and patient performance status:

For Peritoneal Carcinomatosis:

1. Cytoreductive Surgery (CRS) with HIPEC:

   • Recommended for selected patients with limited peritoneal disease
   • Best for those with good performance status, limited disease burden (Peritoneal Cancer Index <20)
   • Goal is complete removal of all visible tumor followed by heated chemotherapy
   • Can achieve median survival up to 42.9 months with complete cytoreduction 5

2. Systemic Chemotherapy:

   • Mainstay for patients with extensive disease or poor performance status
   • Regimen selection based on primary tumor type:
     • Platinum-based regimens for ovarian-like carcinomatosis
     • Oxaliplatin-based regimens (FOLFOX) for colorectal origin
     • Platinum plus etoposide for poorly differentiated neuroendocrine carcinomas 5

3. Palliative Management:

   • For symptom control in advanced disease
   • Addresses bowel obstruction, ascites, pain using medications like octreotide, antiemetics, opioids
   • May include interventional options such as endoscopic stent placement or percutaneous drainage 5

For Leptomeningeal Carcinomatosis:

• Treatment is highly individualized based on primary tumor and extent of disease
• Options include intrathecal chemotherapy, systemic therapy, and radiation therapy 4

Prognostic Factors

Poor prognostic factors include:

• Poor ECOG performance status
• Male sex
• Higher number of metastatically involved organs
• Presence of liver metastases
• Adenocarcinoma histology
• Elevated alkaline phosphatase and LDH 5

Treatment Response Evaluation

• Evaluate response after 2-3 chemotherapy cycles using appropriate imaging
• Completeness of cytoreduction is the most important prognostic factor for peritoneal carcinomatosis 5

Clinical Pitfalls and Considerations

1. Avoid delay in diagnosis: Carcinomatosis often presents with nonspecific symptoms; maintain high clinical suspicion in patients with known malignancy.

2. Patient selection for aggressive therapy: Not all patients benefit from CRS-HIPEC; careful selection based on performance status, disease extent, and primary tumor is critical.

3. Primary tumor identification: In cases of carcinomatosis of unknown primary, extensive workup is necessary to identify the origin, as treatment approaches differ significantly.

4. Balancing quality of life: Given the poor prognosis in many cases, treatment decisions must carefully weigh potential survival benefit against treatment-related morbidity.

5. Multidisciplinary approach: Management decisions should involve surgical oncology, medical oncology, radiology, and palliative care to optimize outcomes.