What is carcinomatosis?

What is Carcinomatosis?

Carcinomatosis is the widespread dissemination of cancer cells throughout a body cavity, most commonly the peritoneal cavity (peritoneal carcinomatosis), characterized by multiple tumor deposits on serosal surfaces arising from primary malignancies of the gastrointestinal tract, ovary, or other abdominal organs. 1, 2

Definition and Pathophysiology

• Carcinomatosis represents an advanced stage of cancer where malignant epithelial cells (carcinoma) have spread diffusely throughout a body cavity, distinguishing it from localized metastases 3, 2
• The term specifically refers to cancer arising from epithelial cells that have breached the basement membrane and disseminated beyond the primary organ 3
• Peritoneal carcinomatosis is the most common form, occurring when abdominal or pelvic cancers seed throughout the peritoneal cavity 1, 2

Common Primary Tumor Origins

• Gastrointestinal tract cancers (colorectal, gastric, pancreatic) are frequent sources of peritoneal carcinomatosis 4, 1
• Ovarian cancer commonly presents with peritoneal spread at diagnosis 4
• Gastric cancer can lead to disseminated carcinomatosis of the bone marrow, though this is rare 5
• Appendiceal cancers, particularly pseudomyxoma peritonei, represent a distinct subset with better prognosis 1

Clinical Presentation

• Patients typically present with ascites (fluid accumulation), abdominal distension, pain, and bowel obstruction 4, 2
• Constitutional symptoms include weight loss, cachexia, and fatigue 2
• The condition causes significant patient discomfort and impaired quality of life 2

Diagnostic Approach

• CT imaging of the chest, abdomen, and pelvis with contrast is the primary diagnostic modality 4
• The Peritoneal Cancer Index (PCI) quantifies the extent of peritoneal disease distribution, with PCI <20 indicating more limited disease 4
• MRI can provide additional information for treatment planning 4
• Histopathological confirmation distinguishes carcinomatosis from other conditions and identifies the primary tumor type 4

Prognostic Significance

• Historically considered a terminal condition with median survival measured in months 1, 2
• Prognosis varies significantly based on primary tumor histology, extent of disease (PCI score), and completeness of potential cytoreduction 4, 1
• Pseudomyxoma peritonei and selected colorectal peritoneal carcinomatosis cases have better outcomes with aggressive treatment 1
• Disseminated carcinomatosis of bone marrow from gastric cancer carries particularly poor prognosis (less than one year survival) 5

Modern Treatment Paradigm

• Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has transformed management for selected patients 4, 1
• Patient selection is critical: good performance status, limited peritoneal disease (PCI <20), minimal small bowel involvement, and no extraabdominal metastases are key criteria 4
• Complete cytoreduction with no visible residual disease is mandatory for long-term benefit 1, 2
• This approach should only be performed in specialized high-volume centers with expertise in peritoneal surface malignancies 4

Important Caveats

• Not all peritoneal carcinomatosis is amenable to aggressive surgical treatment—systemic chemotherapy alone remains standard for many patients 4
• The distinction between carcinomatosis (epithelial origin) and sarcomatosis (mesenchymal origin) is critical, as treatment approaches differ fundamentally 4, 6
• Leptomeningeal carcinomatosis represents spread to the central nervous system and presents with headache, confusion, and cranial nerve deficits 4