Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a specialized, minimally invasive surgical technique designed to deliver chemotherapy directly into the abdominal cavity. This approach targets certain cancers that have spread to the peritoneal lining. PIPAC aims to concentrate the chemotherapy at the site of the cancer, potentially enhancing its effectiveness while reducing exposure to the rest of the body.
The PIPAC Surgical Procedure
PIPAC surgery is performed using a laparoscopic approach, which involves making small incisions, typically 5-12 millimeters, in the abdominal wall. Through these incisions, surgeons insert thin tubes called trocars to create ports for a camera and specialized instruments. The abdominal cavity is then gently inflated with carbon dioxide gas to create a working space and maintain pressure, usually around 12 mmHg.
Once the abdominal cavity is expanded, a device called a Capnopen is introduced. This nebulizer tool, adapted from automotive fuel injection technology, converts liquid chemotherapy drugs into a fine, pressurized aerosolized mist. The chemotherapy, often a low dose of agents like oxaliplatin, cisplatin, or doxorubicin, is then sprayed directly into the peritoneal cavity.
The aerosolized delivery under pressure allows the chemotherapy to spread more evenly throughout the abdominal cavity and penetrate deeper into cancerous tissues compared to liquid delivery methods. The mist remains in the abdomen under pressure for about 30 minutes to allow for absorption by the cancer cells. After this period, the gas and any remaining aerosol are safely removed from the body.
The entire PIPAC procedure typically takes 60 to 90 minutes. During the procedure, biopsies of the abdominal cavity are performed, and the peritoneal cancer index (PCI) may be evaluated. These assessments provide an objective analysis of the patient’s response to chemotherapy.
Conditions Treated by PIPAC
PIPAC is primarily considered for patients with peritoneal carcinomatosis, where cancer cells from a primary tumor have spread to the peritoneum. This treatment is often explored when systemic (whole-body) chemotherapy has become less effective or poorly tolerated, or when surgical removal of the cancer is not feasible due to the extent of the disease.
Cancers that frequently lead to peritoneal carcinomatosis and may be treated with PIPAC include ovarian cancer, especially platinum-resistant recurrent cases, and gastrointestinal cancers such as gastric, colorectal, and appendiceal cancers. Peritoneal mesothelioma, a rare cancer affecting the peritoneum directly, may also be considered.
PIPAC is generally used as a palliative treatment to manage symptoms, improve quality of life, and potentially extend life expectancy. It can help slow or stop cancer from spreading and may reduce symptoms like fluid buildup in the belly. In some instances, PIPAC may shrink tumors enough to make subsequent surgical removal possible for a small percentage of patients, potentially up to 15% in clinical trials.
Patient Experience and Recovery
Before undergoing a PIPAC procedure, patients may receive medication to prevent blood clots. The procedure is performed under general anesthesia.
Immediately following PIPAC surgery, patients typically experience a relatively short hospital stay, often one to two days. Some centers may even perform it in an outpatient setting if the patient meets specific criteria, such as adequate pain relief and no urination problems.
Common short-term effects after PIPAC are generally mild and may include slight abdominal pain, general discomfort, and mild nausea. These effects are usually manageable with pain medication and tend not to last long. Compared to traditional systemic chemotherapy, PIPAC often results in fewer side effects like hair loss, vomiting, or severe gastrointestinal issues because the chemotherapy is localized to the abdomen.
PIPAC treatments are typically repeated every six to eight weeks, and patients may undergo an average of three procedures before their disease is reassessed. This allows for multiple opportunities to monitor tumor response. Patients can often resume systemic chemotherapy within approximately 14 days after a PIPAC session, indicating a minimal impact on their overall functional reserves.