The peritoneal carcinomatosis index (PCI) is a crucial tool used by oncologists and surgeons to assess the extent of cancer spread in the peritoneal cavity. This assessment is particularly relevant in the context of certain types of cancer, such as ovarian cancer, stomach cancer, colorectal and appendiceal cancer and peritoneal mesothelioma, which have a tendency to spread along the peritoneum, the membrane that lines the abdominal cavity and the organs within it.
What is the Peritoneal Carcinomatosis Index (PCI)?
The PCI is a quantification tool that assesses the tumor burden of the peritoneum in peritoneal carcinomatosis. It was introduced by the French surgeon Paul H. Sugarbaker in the 1980s. This index helps to determine the patient’s prognosis and to plan the most appropriate treatment, which may include cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). For patients with high PCI or unresectable disease there are other options available such as pressurized intraperitoneal aerosolized chemotherapy (PIPAC).
How PCI is calculated
Assessment method
PCI is calculated by evaluating the size and location of tumors in different regions of the abdomen, divided into 12 regions, with a scale ranging from 0 to 39. A higher value indicates a greater extent of disease.
PCI assessment is usually performed during minimally invasive exploratory surgery (laparoscopy) or by advanced imaging techniques. The abdomen is divided into 13 regions:
1. mesogastrium (center of the abdomen).
2. Right hypochondrium.
3. Area between both hypochondrium.
4. Left hypochondrium.
5. Left iliac fossa.
6. Pelvis.
7. Right iliac fossa.
8. Right hypochondrium.
9. Small bowel region (divided into 4 quadrants).
PCI scoring
For each of these regions, a score is assigned based on the size of the observed tumor implants:
– 0: No visible tumor implants.
– 1: Tumor implants smaller than 0.5 cm.
– 2: Tumor implants between 0.5 cm and 5 cm.
– 3: Tumor implants larger than 5 cm or clusters of implants.
The sum of the scores of all regions gives the total PCI value, which can vary between 0 and 39.
Importance of PCI in cancer treatment
Treatment planning
Patients with a low to moderate PCI may be candidates for cytoreductive surgery, where an attempt is made to remove all visible tumor tissue. This surgery is often accompanied by HIPEC, a procedure in which heated chemotherapy is administered directly into the peritoneal cavity to kill residual cancer cells.
– In patients with peritoneal metastases of colorectal origin, with PCI above 16, cytoreduction surgery and HIPEC are not recommended because the prognostic impact does not outweigh the benefit of administering systemic chemotherapy alone.
– In patients with peritoneal metastases and synchronous liver metastases of colorectal origin, it is not recommended to treat patients with a PCI greater than 12 and more than three liver metastases. Although if the metastases are all in the same nodule, they can be treated.
– Patients with gastric cancer and a PCI greater than seven, cytoreduction surgery and HIPEC are also not recommended. The prognostic impact is not superior to the patient receiving palliative chemotherapy.
– Patients with unresectable disease or elevated PCI (greater than 16 in colorectal and greater than 7 in gastric cancer) are candidates for treatment with PIPAC.
“In other pathologies, what limits treatment is not the number of PCI, but the location of the tumors. It is crucial that all tumor implants are in organs that can be removed. Some areas, such as the small bowel, are unresectable if they are badly affected. A patient needs at least one meter of functional small bowel. Another unresectable area is the hepatic hilum; if the vascular structures in that area are affected, the disease is considered unresectable,” explains Dr. Delia Cortés Guiral, director of IVOQA.
Prognosis and survival
The prognosis depends on several factors, including the type of cancer, the PCI, the response to treatment and the patient’s general state of health. However, the use of PCI allows for better stratification of patients and more personalized treatment planning, which may improve overall outcomes, since in general patients with low PCI are more likely to have complete cytoreduction surgery and this fact is the major prognostic factor in patients with peritoneal involvement.
PCI in IVOQA
At present, treatments for peritoneal carcinomatosis remain limited and prognostically guarded.
Multimodal management combining systemic chemotherapy, complete cytoreductive surgery, combined with the administration of intraperitoneal chemotherapy (HIPEC), is an effective alternative for patients with disease of limited extent, and which does not involve areas known to be unresectable (such as very extensive involvement of the surface of the small bowel, hepatic hilum, etc.).
This surgery, with or without HIPEC, can be performed in our center by conventional open surgery. In addition, we offer for highly selected patients the possibility to perform this surgery by minimally invasive route (laparoscopy) and we also offer PIPAC and ePIPAC to patients with very high PCI or unresectable disease.
PCI not only helps determine the feasibility of procedures such as cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC), but also provides crucial guidance for patient prognosis. A low PCI is associated with better outcomes and longer survival, while a high PCI indicates more advanced disease and a less favorable prognosis.
For more information and personalized assessments, it is recommended to consult IVOQA specialists, who can provide guidance and treatment options based on the latest research and technologies available.
