Peritoneal carcinomatosis is an advanced stage of cancer involving the peritoneum, the thin membrane lining the abdominal cavity and covering the organs within it. When cancer spreads to this lining, it is known as peritoneal surface malignancy. Prognosis has improved due to specialized measurement tools and aggressive, combined treatment strategies. These advancements allow medical teams to accurately assess the extent of the disease and determine which patients may benefit from complex procedures.
Understanding Peritoneal Carcinomatosis
The peritoneum acts as a protective barrier within the abdomen. Peritoneal carcinomatosis develops when cancer cells detach from a primary tumor, often located elsewhere in the abdomen, and implant on the peritoneal surfaces. This form of cancer is considered a secondary or metastatic disease, indicating an advanced stage.
Primary cancers leading to this spread include those originating in the appendix, colon, rectum, stomach, and ovaries. Once the cancer cells settle on the peritoneal lining, they form multiple small tumor nodules across the surface. This spread can lead to complications like a buildup of fluid in the abdomen, known as ascites, which causes bloating and discomfort.
As the disease progresses, the growing tumor nodules can press on or wrap around the intestines, leading to blockages or obstruction. Since the disease is confined to the abdominal cavity, it is treated differently than cancers that have spread throughout the body via the bloodstream. The severity of the disease varies depending on the number and size of these tumor implants.
Measuring Disease Extent
The Peritoneal Carcinomatosis Index (PCI) is a standardized scoring system developed by Dr. Paul Sugarbaker. It measures the extent and distribution of cancer spread within the abdomen to determine prognosis and guide treatment planning. The total PCI score ranges from 0 to 39, where higher numbers indicate a greater tumor burden.
To calculate the PCI, the abdominal cavity is systematically divided into 13 regions. These regions include nine sections of the abdominopelvic area and four sections of the small bowel. During surgical exploration, the surgeon examines each of the 13 regions individually.
For each region, a score from 0 to 3 is assigned based on the size of the largest tumor nodule. A score of 0 means no tumor is visible. Implants smaller than 0.5 centimeters receive a score of 1; nodules between 0.5 centimeters and 5 centimeters are scored as 2. Implants larger than 5 centimeters, or those merged into a confluent mass, receive a score of 3.
The scores from all 13 regions are added together to determine the final PCI score. This score is a powerful tool because it helps predict the likelihood of a successful complete surgical removal of the tumor. Certain cancer types have established PCI cut-off points, making the PCI a direct determinant of eligibility for complex procedures.
Comprehensive Treatment Approaches
Patients with low to moderate PCI scores may be candidates for a highly specialized, two-part procedure combining Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). This aggressive treatment offers the best chance for long-term survival. It requires a multidisciplinary team and is performed at select medical centers.
Cytoreductive Surgery (CRS)
CRS is the first phase, aiming to remove all visible evidence of the cancer. This involves carefully stripping tumors from the peritoneal lining, a process often called peritonectomy procedures. The surgeon examines the abdomen quadrant by quadrant, removing affected organs (such as portions of the colon, spleen, or omentum) to ensure all macroscopic disease is gone.
Hyperthermic Intraperitoneal Chemotherapy (HIPEC)
Immediately following CRS, the second phase, HIPEC, is performed. This involves circulating a heated chemotherapy solution directly into the abdominal cavity. Tubes and temperature probes warm the solution to about 41 to 43 degrees Celsius, slightly above normal body temperature.
The chemotherapy is circulated for a specific duration, often around 90 minutes. Heating the drug is twofold: the elevated temperature helps kill cancer cells, and it increases the penetration and effectiveness of the chemotherapy agent. This direct application targets remaining microscopic cancer cells while limiting systemic side effects.
The Peritoneal Carcinomatosis Index, or PCI, is the quantitative scoring system surgeons use to measure the extent and distribution of cancer spread within the abdomen. Developed by Dr. Paul Sugarbaker, the PCI provides a standardized numerical value that helps determine a patient’s prognosis and guides treatment planning. The total PCI score can range from 0 to 39, with higher numbers indicating a greater tumor burden and more advanced disease.
To calculate the PCI, the entire abdominal cavity is systematically divided into 13 distinct regions. These regions include nine sections of the abdominopelvic area and four specific sections of the small bowel. During a surgical exploration or staging laparoscopy, the surgeon examines each of the 13 regions individually.
For each region, a score from 0 to 3 is assigned based on the size of the largest tumor nodule found. A score of 0 signifies no tumor is visible, while a score of 1 is given for implants smaller than 0.5 centimeters. Nodules between 0.5 centimeters and 5 centimeters are scored as 2, and any implants larger than 5 centimeters, or those that have merged into a confluent mass, receive a score of 3.
The scores from all 13 regions are then added together to determine the final PCI score. This score is a powerful tool because it helps predict the likelihood of a successful complete surgical removal of the tumor. For instance, certain cancer types have established PCI cut-off points, above which aggressive surgical treatment is not typically recommended, making the PCI a direct determinant of eligibility for complex procedures.
Comprehensive Treatment Approaches
For patients with peritoneal carcinomatosis who have a low to moderate PCI score, a highly specialized, two-part procedure offers the best chance for long-term survival. This treatment combines an aggressive operation called Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). It is a major surgical effort that requires a multidisciplinary team and is typically only performed at select medical centers.
Cytoreductive Surgery is the first phase, where the goal is to remove all visible evidence of the cancer. This extensive operation involves carefully stripping tumors from the peritoneal lining, a process often referred to as peritonectomy procedures. The surgeon meticulously examines the abdomen quadrant by quadrant, removing any affected organs or parts of organs, such as portions of the colon, the spleen, or the omentum, to ensure all macroscopic disease is gone.
Immediately following the completion of CRS, the second phase, HIPEC, is performed in the operating room. Hyperthermic Intraperitoneal Chemotherapy involves circulating a heated chemotherapy solution directly into the abdominal cavity. Tubes and temperature probes are placed into the abdomen, and the solution is warmed to a temperature of about 41 to 43 degrees Celsius, which is slightly above normal body temperature.
The chemotherapy is circulated for a specific duration, which is often around 90 minutes, to treat the entire area. The rationale for heating the drug is twofold: the elevated temperature itself helps kill cancer cells, and the heat increases the penetration and effectiveness of the chemotherapy agent. This direct, topical application targets any remaining microscopic cancer cells that the surgeon could not see, while limiting the drug’s systemic side effects on the rest of the body.