13 Peritoneal Regions

The 13 Peritoneal Regions are a standardized anatomical map dividing the abdominal cavity into thirteen zones used to score how much tumor is present in each area during peritoneal mesothelioma surgery. Surgeons assign a lesion size score (0 to 3) in each region and add them to produce the Peritoneal Cancer Index (PCI), a number from 0 to 39 that reflects total disease burden.

Origin

The system was developed in the early 1990s by Dr. Paul Sugarbaker at the Washington Cancer Institute as part of his work standardizing cytoreductive surgery and HIPEC (heated intraperitoneal chemotherapy) for peritoneal surface malignancies. It has since become the international standard for describing the extent of peritoneal disease.

Significance in Asbestos Context

For patients with peritoneal mesothelioma, a cancer of the abdominal lining caused by swallowed or inhaled asbestos fibers, the PCI score derived from these 13 regions is one of the most important numbers in their chart. It helps surgeons decide whether cytoreductive surgery with HIPEC is feasible, predicts how complete a tumor removal can be, and strongly influences prognosis. Patients should ask their oncologist or surgeon what their PCI score is, whether it was assigned by imaging (CT or MRI) or at the time of diagnostic laparoscopy, and how that score affects their eligibility for surgery at a specialized peritoneal mesothelioma center. The PCI also appears in operative reports and pathology summaries that may be reviewed by legal teams documenting the severity of disease.

Example Sentence

After her diagnostic laparoscopy, the surgeon told her that her PCI score across the 13 peritoneal regions was 18, which made her a candidate for cytoreductive surgery with HIPEC.

Related Terms

Peritoneal Mesothelioma, Peritoneal Cancer Index (PCI), Cytoreductive Surgery, HIPEC, Completeness of Cytoreduction Score, Diagnostic Laparoscopy

Notes

• Request a copy of any operative report or laparoscopy report that lists a PCI score, and confirm whether each of the 13 regions was individually scored. This level of detail matters for second opinions at specialized centers.
• If you are being evaluated for cytoreductive surgery and HIPEC, ask whether the surgeon performs a high volume of these procedures specifically for peritoneal mesothelioma; outcomes are strongly tied to center experience.
• Preserve all imaging (CT, MRI, PET) along with the radiology reports, because PCI estimates from imaging often underestimate the true disease burden found at surgery, and both numbers may be relevant to your medical and legal records.
• A higher PCI does not automatically rule out treatment. Some patients with diffuse disease still benefit from surgery, systemic chemotherapy, or immunotherapy, so ask about all options if you are told you are not a surgical candidate.