Peritoneal Carcinomatosis

Peritoneal Carcinomatosis

Dimitri Alexander Petrov, MD

Table of Contents

Background
Presentation and Diagnosis
Peritoneal Cancer Index (PCI)
Management

Background

Definition: Malignancy of the Peritoneum Covered in Multiple Carcinomatous Masses (“Peritoneal Studding”)

The Most Common Malignant Process of the Peritoneal Cavity

Etiology

  • Primary Peritoneal Carcinomatosis: Originates within the Peritoneum
    • Mesothelioma is the Most Common Primary Cause
  • Secondary Peritoneal Carcinomatosis: Originates from Another Source

Secondary Sources

  • Stomach
  • Small Bowel
  • Colorectal
  • Appendix
  • Ovarian – The Most Common Source
  • Pancreas
  • Liver
  • Biliary Tract
  • Kidney
  • Breast – The Most Common Extra-Abdominal Source
  • Lung

Peritoneal Implants Most Often Locate at Sites of Relative Physiologic Fluid Stasis – Pelvic Peritoneal Reflections, Paracolic Gutters, Superior Sigmoid Mesocolon, Ileocolic Region, and Right Subdiaphragmatic Space

Pseudomyxoma Peritonei (PMP): Describes Diffuse Gelatinous Ascites with Mucinous Peritoneal Implants

  • Most Common Source: Mucinous Cystadenoma of Appendix

Peritoneal Carcinomatosis on Laparoscopy 1

Presentation and Diagnosis

Symptoms

  • Increasing Abdominal Girth – The Most Common Presenting Symptom
    • Ascites Caused by Increased Peritoneal Fluid Secretion and Impaired Reabsorption
  • Inguinal Hernia – The Second Most Common Presenting Symptom
  • Weight Loss
  • Abdominal Pain
  • Nausea and Vomiting
  • Bowel Obstruction
  • Diarrhea
  • Dyspnea

Diagnosis Can Be Made by Imaging (CT), Paracentesis with Fluid Analysis, Omental Biopsy, or Laparoscopy with Implant Biopsy

Radiographic Findings

  • Ascites
  • “Organ Scalloping” – Scattered Peritoneal Nodules
  • “Omental Caking” – Increased Density and Nodular Lesions
  • Mesenteric Infiltration
  • Stomach Wall Thickening
  • Sleeve-Like Growth Along the Bowel Serosa

Paracentesis is Generally Able to Achieve Diagnose and Avoid the Need for More Invasive Laparoscopic Biopsy

Paracentesis Orders

  • Cytology
  • Cell Count and Differential
  • Protein and Albumin
  • Glucose
  • Lactate Dehydrogenase
  • Culture

If Discovered Intraoperatively for Small Bowel Obstruction (SBO): Biopsy Peritoneal Implants, Biopsy Omentum, Collect Fluid for Cytology, and Abort Operation

CT Showing Organ Scalloping (Arrow) of Peritoneal Carcinomatosis 2

Peritoneal Cancer Index (PCI)

Peritoneal Cancer Index (PCI)

  • Grading Index Used for Research and to Objectively Describe the Extent of Tumor Burden
  • Score = Sum of the Largest Lesion Size (0-3) in Each of 13 Defined Regions
  • Scores Range from 0-39

Regions

  • Region 0: Central
  • Region 1: RUQ
  • Region 2: Epigastrium
  • Region 3: LUQ
  • Region 4: Left Flank
  • Region 5: LLQ
  • Region 6: Pelvis
  • Region 7: RLQ
  • Region 8: Right Flank
  • Region 9: Upper Jejunum
  • Region 10: Lower Jejunum
  • Region 11: Upper Ileum
  • Region 12: Lower Ileum

Lesion Size Score

  • 0 Points: No Tumor
  • 1 Point: ≤ 0.5 cm
  • 2 Points: ≤ 5.0 cm
  • 3 Points: > 5.0 cm

Peritoneal Cancer Index (PCI) Diagram 3

Management

Primary Treatment: Cytoreductive Surgery (CRS) and HIPEC

Managed Nonoperatively with Systemic Chemotherapy if Extraperitoneal Metastases or Other Contraindications are Present

Contraindications to CRS/HIPEC

  • Absolute Contraindications:
    • Extra-Abdominal Metastases
    • Unresectable or Not Amenable to Complete Cytoreduction
    • Multifocal Malignant Small Bowel Obstruction
    • Poor Performance Status – Heart Failure, COPD, Renal Failure, etc.
  • Relative Contraindications:
    • Disease Progression on Systemic Therapy
    • Short-Disease Free Interval (< 6 Months) – If Metachronous
    • Peritoneal Cancer Index (PCI) > 20
    • High-Grade Adenocarcinoma
    • Elderly (Age ≥ 65 Years)
    • Morbid Obesity (BMI ≥ 40)

Cytoreductive Surgery (CRS)

  • Definition: Surgery to Decrease the Tumor Burden
  • Resect All Bulky Tumor Implants and Leave No Residual Tumors > 2 mm
    • Chemotherapy (HIPEC) is Unable to Reliably Penetrate Tumors > 2 mm – No Survival Benefit without a Complete Cytoreduction
    • MNEMONIC: Nothing Over 2 mm to Move onto the 2nd Step
  • Abdominal Wall Masses Should Be Excised with the Associated Peritoneum

Completeness of Cytoreduction (CC) Score

  • A Scoring System Used to Grade How Complete Cytoreduction Was
  • Scores:
    • CC-0: No Disease
    • CC-1: ≤ 2.5 mm
    • CC-2: ≤ 2.5 cm
    • CC-3: > 2.5 cm
  • CC-0 and CC-1 are Considered “Complete Cytoreduction”
  • CC-2 and CC-3 are Considered “Incomplete Cytoreduction”
  • CC Score is a Significant Prognostic Indicator

HIPEC (Hyperthermic Intraperitoneal Chemotherapy)

  • Heated Chemotherapeutic Drugs are Infused into the Peritoneal Cavity
    • Avoids Systemic Circulation to Minimize Toxicity
    • Heating Increases Penetration and Cytotoxicity
    • Most Common Agents: Oxaliplatin, Cisplatin, Doxorubicin, and Mitomycin-C
  • Performed After Surgical Debulking During the Same Operation – Adhesions Later Create a Barrier Preventing Uniform Distribution
  • Requires No Residual Tumors > 2 mm for Chemotherapy to Penetrate
  • Often Described as a “Shake and Bake” During an Approximately 30-120 Minute Infusion

EPIC (Early Postoperative Intraperitoneal Chemotherapy)

  • Chemotherapy (Not Heated) is Given Via a Catheter or Subcutaneous Port
  • Administered on Postoperative Days #1-5 After Surgical Debulking
  • Able to Give Multiple Cycles with Longer Dwell Times
  • Greater Risk of Systemic Absorption/Toxicity – HIPEC is Typically Favored

Management of Malignant Bowel Obstruction: *See Small Bowel Obstruction (SBO)

References

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  2. Singh S, Devi YS, Bhalothia S, Gunasekaran V. Peritoneal Carcinomatosis: Pictorial Review of Computed Tomography Findings. International Journal of Advanced Research. 2016;4(7):735–748. (License: CC BY-4.0)
  3. Harmon RL, Sugarbaker PH. Prognostic indicators in peritoneal carcinomatosis from gastrointestinal cancer. Int Semin Surg Oncol. 2005 Feb 8;2(1):3. (License: CC BY-2.0)