Peritoneal Carcinomatosis: Aiding Clinicians by Quantifying Disease Burden (PCI)

Abstract

Peritoneal metastases are a relatively common location for metastases, particularly from tumors of the abdomen and pelvis. Manifestation of peritoneal disease has a wide spectrum including ascites, omental caking, omental nodularity or masses, and diffuse enhancement with nodular thickening of the parietal peritoneum of the pelvis. Mesenteric effacement, luminal narrowing, bowel wall thickening, hyperenhancement indicate small bowel disease Peritoneal cancer index (PCI) is a measure of disease spread of peritoneal carcinomatosis that can be evaluated radiographically by CT. PCI is scored across 13 abdominal regions with the composite score reflecting both tumor size and distribution producing a quantitative score. The abdomen and the pelvis are divided by lines into nine regions (regions 0-8). The small bowel is then divided into four regions. Regions 9 and 10 define upper and lower portions of the jejunum, and regions 11 and 12 define the upper and lower portions of the ileum. The lesion size (LS) of the largest implant is scored as lesion size 0 through 3 (LS-0 to LS-3). LS-0 means no implants. LS-1 refers to implants that are visible up to 0.5 cm in greatest diameter. LS-2 identifies nodules greater than 0.5 cm and up to 5 cm. LS-3 refers to implants 5 cm or greater. If an organ is coated by a mat of tumor (confluent disease) or if there is tissue adhesions, the region or site is also scored as LS-3. The lesion sizes are then summed for all regions. A numeric score from 0-39 indicates the extent of the disease. Preoperatively, the radiologist should review a CT scan of the thorax, abdomen, and pelvis after administration of oral and IV contrast material to initially exclude extraabdominal metastatic disease.