What is pressurized intraperitoneal aerosol chemotherapy?

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is an experimental treatment for cancers that have spread to the lining of the abdominal cavity, known as the peritoneum. The term "intraperitoneal" means the treatment is delivered directly inside the abdominal cavity, where the cancer is located. For now, PIPAC is considered palliative, meaning that it's used to help manage symptoms, not to cure the cancer.

PIPAC is the delivery of chemotherapy as a pressurized mist directly into the abdomen during a minimally invasive surgery called laparoscopy. The pressure helps the medicine absorb into the cancer tissue and spread more evenly. Unlike other treatments, PIPAC does not include surgical removal of the cancer. PIPAC is repeated about every six weeks, while you remain on whole-body, also called systemic, chemotherapy.

PIPAC was first used to relieve symptoms in people whose cancer no longer responded to other treatments. Today, doctors are also studying whether it can help extend life in people with cancer or prevent cancer from returning.

When is PIPAC used?

Healthcare professionals consider PIPAC for people with advanced peritoneal cancer when surgery to cure the cancer is not possible or when the cancer has gotten worse while traditional therapies are in use. PIPAC is less toxic than systemic chemotherapy and less invasive than open surgery.

PIPAC may be used to:

• Slow or stop the cancer from spreading.
• Shrink tumors so they are small enough to surgically remove. Up to 15% of people who received PIPAC in clinical trials were later able to have surgery to remove tumors.
• Relieve symptoms such as fluid buildup in the belly, called ascites.
• Reduce hospital stays and side effects. Compared with systemic chemotherapy alone, PIPAC in addition to systemic chemotherapy results in fewer and shorter hospitalizations, longer overall survival, and better quality of life.

What cancers does PIPAC treat?

PIPAC treats cancers that start in other organs but spread to the peritoneum. These are called peritoneal metastases. PIPAC is most commonly used to treat peritoneal metastases cancers such as:

• Colon or rectal cancer.
• Appendix cancer.
• Stomach cancer.
• Ovarian cancer.

How is PIPAC done?

PIPAC is done during a short surgery called laparoscopy. First, a small camera and special instruments are put into the abdomen through tiny cuts. Then, chemotherapy medicine is turned into a fine, aerosolized mist and sprayed inside the abdominal cavity using a high-pressure device.

During the procedure, the belly is gently inflated with a combination of carbon dioxide gas and chemotherapy medicine to create space and pressure. This helps the chemotherapy medicine spread evenly and go deeper into cancer tissue. The mist stays in the belly under pressure for about 30 minutes, then the gas is safely removed using a closed air waste evacuation system. The entire procedure takes about an hour and typically does not require a hospital stay. PIPAC can usually be repeated every 6 to 8 weeks.

What are the side effects of PIPAC?

Because PIPAC uses far lower doses than standard chemotherapy treatment, it's generally well tolerated. Most side effects are mild and temporary. They may include:

• Abdominal pain or cramping.
• Upset stomach or vomiting.
• Bloating.
• Temporary loss of appetite.
• Changes in bowel habits, such as constipation or diarrhea.

Serious side effects are rare but can include:

• Infection related to surgery.
• Surgical complications, such as bowel or organ injury.
• Scar tissue formation inside the abdomen, which may slow down or block the intestines as food moves through the body.

Most people go home the same day and recover within a week.

What is the success rate of PIPAC?

Success rates for PIPAC vary, as it's used for different cancers and in different situations. The chance of benefit is highest when PIPAC is repeated and the cancer is limited to the abdomen. Outcomes include:

• Slowed or stopped cancer progression in about 50% to 75% of people with colon, rectal or ovarian cancer.
• Improved quality of life for most people who have PIPAC.
• Longer survival for people with colon, rectal or appendix cancers, compared with survival after systemic chemotherapy in some studies.
• Better control of symptoms, such as abdominal fluid buildup, called ascites, in some people.

More studies are ongoing to better understand how well PIPAC works across different cancers and identify which people are likely to benefit the most.

Is cytoreductive surgery done before or after PIPAC?

Cytoreductive surgery (CRS) is a procedure to remove all visible cancer from the peritoneum and other organs in the abdomen. CRS also is known as debulking surgery.

People who have already had CRS can receive PIPAC. Sometimes, PIPAC can help shrink cancer enough that CRS becomes possible, even if healthcare professionals first thought the cancer was too widespread to remove.

PIPAC and HIPEC: What's the difference?

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) and hyperthermic intraperitoneal chemotherapy (HIPEC) are both treatments that deliver chemotherapy directly into the abdominal cavity. However, the procedures have some key differences, including:

• Surgery requirements:
  • HIPEC is usually given right after cytoreductive surgery (CRS), which is a major procedure. CRS is done to remove as much cancer as possible.
  • PIPAC is given during a short, minimally invasive laparoscopic procedure and does not require cancer removal.
• Chemotherapy delivery:
  • HIPEC uses heated liquid chemotherapy that is poured into the abdominal cavity.
  • PIPAC uses a pressurized chemotherapy mist that spreads more evenly and penetrates deeper into cancer tissue.
• Treatment schedule:
  • HIPEC is usually done once.
  • PIPAC can be repeated every 6 to 8 weeks.
• Side effects and recovery:
  • HIPEC is more invasive and has a longer recovery time because it is combined with CRS.
  • PIPAC has fewer side effects and a quicker recovery time.
• Outcomes:
  • HIPEC offers a potential cure.
  • PIPAC is considered palliative, meaning that it's used to help manage symptoms, not to cure the cancer.

Where are PIPAC procedures performed in the United States?

PIPAC is still a new treatment in the U.S. and is currently available only at a small number of specialized cancer centers. These centers have taken part in early U.S. clinical trials studying PIPAC for cancers such as those of the colon, rectum, appendix, stomach and ovaries.

Since PIPAC is still being studied, most procedures are done as part of clinical trials. Talk with your healthcare team to see whether a trial is available near you or whether you can get a referral.

Are there clinical trials for PIPAC?

Yes. There are several ongoing clinical trials for PIPAC in the United States and internationally. These trials are testing how safe and effective PIPAC is for different cancers that have spread to the abdominal cavity.

Some trials are testing PIPAC alone, while others are combining it with systemic chemotherapy. A few studies are exploring the use of PIPAC before or after surgery to prevent cancer from coming back.

Does insurance cover PIPAC?

PIPAC is mainly offered through clinical trials, which often are not covered by insurance. Instead, the cost of the procedure and related care is often covered by the study sponsor or the hospital running the trial.

However, some people may be able to get some coverage for parts of their care, such as lab tests, imaging or hospital stays, depending on their insurance and the trial setups. If you're interested in PIPAC, it's important to:

• Ask the research team whether the trial sponsor or hospital covers costs.
• Contact your insurance company to ask what is and isn't covered.
• Request financial counseling from the hospital, if needed.

Coverage may change as more evidence becomes available and if PIPAC becomes an approved standard treatment in the future.

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July 19, 2025 See more In-depth