Peritoneal washing is a medical procedure involving the collection of fluid from the peritoneal cavity, which is located within the abdomen. This cavity is a space between two layers of a thin membrane called the peritoneum. The peritoneum lines the abdominal walls and covers organs such as the intestines, liver, and stomach, providing protection and support. During the procedure, a sterile saltwater solution is introduced into this space and then collected for laboratory analysis. This process aims to retrieve cells that may be present in the peritoneal fluid.
Why Peritoneal Washing Is Performed
Doctors primarily perform peritoneal washing to detect cancer cells and determine the extent of cancer spread, known as staging. This procedure is commonly used for gynecological cancers, such as ovarian and uterine cancers, and certain gastrointestinal cancers like stomach and pancreatic cancer. Identifying cancer cells in the peritoneal fluid, even if not visible during surgery, helps medical teams understand if the disease has spread beyond the primary tumor site. A positive washing can indicate microscopic spread of cancer that might not be visible otherwise. This information is important for guiding treatment decisions and predicting a patient’s prognosis, as results are included in the staging system for ovarian and fallopian tube cancers.
Peritoneal washing can also be performed during “second-look” surgeries to assess treatment effectiveness or monitor for remaining cancer cells. In some cases, it helps rule out hidden cancers in patients undergoing surgery for conditions thought to be benign, such as endometriosis. While primarily focused on cancer, peritoneal washing can sometimes assist in detecting infections or inflammation within the peritoneal cavity.
The Peritoneal Washing Procedure
Patients typically undergo peritoneal washing during a larger surgical procedure, such as a laparoscopy or open surgery to remove tumors or explore the abdominal area. Before the main operation, patients receive anesthesia for comfort.
The surgeon introduces a sterile saline solution into the peritoneal cavity, usually ranging from 50 to 200 milliliters. This fluid is instilled into various areas, including the pelvis, the right and left paracolic gutters, and beneath the diaphragm. After washing these areas, the solution and any suspended cells are aspirated and collected.
Patients do not typically require specific preparation for the washing beyond what is needed for the primary surgery, such as fasting or adjusting medication. Post-procedure care focuses on recovery from the main surgical intervention, as the washing carries minimal specific risks.
Understanding Peritoneal Washing Results
After collection, the fluid from a peritoneal washing is sent to a laboratory for cytopathology, which involves examining the cells under a microscope. This analysis focuses on identifying any abnormal or malignant (cancerous) cells.
Results are typically reported as “positive,” “negative,” “atypical,” or “suspicious.” A “positive” result indicates malignant cells, meaning cancer has spread to the peritoneal cavity. Conversely, a “negative” result suggests no cancer cells were found. “Atypical” results indicate cells that are not clearly cancerous but are not normal, while “suspicious” suggests a high likelihood of malignancy. For cancer staging, often only an unequivocally positive diagnosis is used, with anything less typically treated as negative.