PIPAC: Pressurized Intraperitoneal Aerosolized Chemotherapy

Editor’s note: This article is for educational purposes only and should not replace medical advice from an oncology team. Patients considering PIPAC should speak with a surgical oncologist, medical oncologist, or a cancer center experienced in peritoneal surface malignancies.

Pressurized intraperitoneal aerosolized chemotherapy, better known by the much friendlier acronym PIPAC, sounds like something NASA might use to clean a spaceship. In reality, it is an innovative cancer treatment approach designed for a very serious problem: cancer that has spread to the lining of the abdominal cavity, called the peritoneum.

Peritoneal metastases can happen with several cancers, including colorectal cancer, ovarian cancer, gastric cancer, appendix cancer, uterine cancer, pancreatic cancer, and peritoneal mesothelioma. The challenge is that the peritoneum is a broad, thin, slick lining that wraps around abdominal organs like a delicate internal wallpaper. When cancer spreads across that surface, it can be difficult for traditional intravenous chemotherapy to reach every tumor deposit effectively.

That is where PIPAC enters the conversation. Instead of sending chemotherapy through the bloodstream and hoping enough of it reaches the abdominal lining, PIPAC delivers chemotherapy directly into the abdomen as a pressurized mist during a minimally invasive laparoscopic procedure. Think of it as regional chemotherapy with better aimnot a magic wand, but a carefully engineered sprayer used in a highly controlled operating room setting.

What Is PIPAC?

PIPAC stands for pressurized intraperitoneal aerosolized chemotherapy. The name describes the treatment almost word for word:

• Pressurized means the medicine is delivered under pressure.
• Intraperitoneal means inside the abdominal cavity.
• Aerosolized means the chemotherapy is converted into a fine mist.
• Chemotherapy means cancer-fighting drugs are used to damage or kill cancer cells.

During PIPAC, a surgeon makes small incisions in the abdomen and uses laparoscopy, a minimally invasive surgical technique, to inspect the abdominal cavity. A special device then turns liquid chemotherapy into an aerosol and distributes it inside the abdomen under pressure. The goal is to improve drug distribution across peritoneal tumors while limiting the amount of chemotherapy circulating through the rest of the body.

PIPAC is most often discussed as a palliative treatment, meaning it is generally used to help control disease, reduce symptoms, improve quality of life, or possibly make other treatments more feasible. It is not usually described as a cure. That distinction matters. In cancer care, honest expectations are not pessimism; they are the seatbelt on the treatment journey.

Why Peritoneal Metastases Are So Hard to Treat

The peritoneum is the thin membrane that lines the abdominal wall and covers many abdominal organs. When cancer cells spread there, they may appear as small nodules, plaques, or widespread deposits. This condition is often called peritoneal carcinomatosis or peritoneal metastasis.

Peritoneal disease creates several treatment challenges. First, tumors may be scattered across a large surface area rather than forming one neat mass. Second, blood supply to some peritoneal tumor deposits may be limited, which can make standard systemic chemotherapy less efficient in that location. Third, symptoms such as abdominal swelling, bowel obstruction, nausea, pain, and fluid buildup known as ascites can interrupt regular cancer treatment.

For some patients, aggressive surgery called cytoreductive surgery, sometimes combined with HIPEC or hyperthermic intraperitoneal chemotherapy, may be an option. But not everyone is healthy enough for major surgery, and not every tumor pattern can be removed safely. PIPAC was developed partly to serve patients who need a regional treatment approach but are not candidates for large open abdominal surgery.

How the PIPAC Procedure Works

PIPAC is performed in an operating room under general anesthesia. The procedure is typically shorter and less invasive than cytoreductive surgery with HIPEC. While details vary by institution and clinical trial protocol, the general process follows a familiar pattern.

Step 1: Laparoscopic Access

The surgeon makes two or more small incisions in the abdomen. A laparoscope, which is a thin camera, is inserted so the surgical team can view the abdominal cavity. Carbon dioxide is used to gently inflate the abdomen, creating working space.

Step 2: Disease Assessment

The surgeon examines the peritoneal cavity and may estimate the amount of visible disease using tools such as the peritoneal cancer index. Biopsies may be taken before or after treatment to evaluate tumor response over time.

Step 3: Chemotherapy Aerosol Delivery

A nebulizer or specialized injector converts chemotherapy into a fine mist. This aerosol is released into the abdominal cavity under pressure. Commonly studied PIPAC drugs include oxaliplatin, cisplatin, doxorubicin, mitomycin, and nab-paclitaxel, depending on the cancer type and study design.

Step 4: Controlled Exposure Time

The aerosol remains in the abdomen for a set period, often around 30 minutes. During this time, the chemotherapy mist can distribute throughout the abdominal cavity and interact with tumor surfaces.

Step 5: Safe Evacuation and Recovery

After the exposure period, the aerosol is removed through a closed safety system to protect operating room staff. The small incisions are closed, and the patient is monitored during recovery. Many patients go home within a day or two, depending on the cancer center, their overall condition, and the treatment protocol.

What Cancers May Be Treated With PIPAC?

PIPAC is being studied or offered in selected centers for cancers that have spread to the peritoneal cavity. These may include:

• Colorectal cancer with peritoneal metastases
• Appendix cancer and pseudomyxoma peritonei
• Gastric or stomach cancer
• Ovarian cancer
• Uterine cancer
• Peritoneal mesothelioma
• Selected pancreatic or biliary tract cancers in clinical trials

Not every patient with these cancers is a candidate. PIPAC is most appropriate when the disease is mainly within the abdominal cavity and the patient can tolerate laparoscopy. If cancer has spread widely outside the abdomen, PIPAC alone may not address the full disease burden because it is a regional treatment, not a whole-body therapy.

PIPAC vs. HIPEC: What Is the Difference?

PIPAC and HIPEC both deliver chemotherapy into the abdomen, but they are not the same treatment.

HIPEC

HIPEC stands for hyperthermic intraperitoneal chemotherapy. It is usually performed after cytoreductive surgery, during which surgeons remove as much visible tumor as possible. Heated liquid chemotherapy is then circulated inside the abdomen. HIPEC is often part of a major operation and may require a longer hospital stay and recovery period.

PIPAC

PIPAC is delivered through laparoscopy and does not require surgical removal of tumor. Chemotherapy is aerosolized rather than circulated as heated liquid. PIPAC can often be repeated every several weeks, allowing doctors to reassess the abdomen, collect biopsies, and monitor response.

In simple terms, HIPEC is typically paired with a big tumor-removal operation, while PIPAC is a smaller laparoscopic procedure designed to deliver chemotherapy directly to peritoneal disease. Both have roles, but patient selection is everything. Cancer treatment is not a buffet where everyone gets the same plate.

Potential Benefits of PIPAC

The interest in pressurized intraperitoneal aerosolized chemotherapy comes from several potential advantages:

More Targeted Drug Delivery

PIPAC places chemotherapy directly into the abdominal cavity, close to the cancer deposits it is meant to treat. This regional approach may help deliver higher local exposure to tumor surfaces while using lower overall drug doses than standard systemic chemotherapy.

Improved Distribution

The combination of aerosolization and pressure is designed to help chemotherapy spread more evenly throughout the peritoneal cavity. This matters because peritoneal disease can hide in corners, folds, and surfaces that are not always easy to reach.

Lower Systemic Exposure

Because PIPAC uses regional delivery, less chemotherapy may circulate through the bloodstream compared with full-dose intravenous chemotherapy. That may reduce certain systemic side effects, although side effects can still occur.

Repeatable Treatment

PIPAC can often be repeated in cycles. This allows the oncology team to evaluate whether tumors are shrinking, stabilizing, or progressing. It also gives doctors a chance to collect tissue samples and adjust the broader treatment plan.

Possible Symptom Relief

For some patients, PIPAC may help manage abdominal symptoms related to peritoneal disease, such as ascites or tumor-related discomfort. Results vary, and symptom improvement should be discussed realistically with the care team.

Risks and Side Effects of PIPAC

PIPAC is minimally invasive, but “minimally invasive” does not mean “risk-free.” It is still surgery, still anesthesia, and still chemotherapy. Possible risks may include:

• Abdominal pain or cramping
• Nausea or vomiting
• Fatigue
• Temporary changes in appetite
• Bleeding or infection at incision sites
• Injury to abdominal organs
• Complications from anesthesia
• Kidney, liver, or blood count changes depending on the chemotherapy used
• Rare but serious complications such as bowel injury or obstruction

Some clinical studies suggest PIPAC can be feasible and well tolerated in carefully selected patients, but the treatment is still being studied. The best outcomes depend on expert patient selection, a trained surgical team, and close coordination between surgical oncology, medical oncology, pharmacy, nursing, anesthesia, and safety teams.

Who Might Be a Candidate for PIPAC?

A patient may be considered for PIPAC if they have cancer involving the peritoneum, are not a good candidate for cytoreductive surgery and HIPEC, and can safely undergo laparoscopy. Many clinical trial protocols also require adequate organ function, acceptable blood counts, and an ECOG performance status showing that the patient is well enough for treatment.

PIPAC may not be recommended if a patient has severe bowel obstruction, extensive scar tissue that prevents safe laparoscopic access, uncontrolled infection, poor overall health, or widespread cancer outside the abdomen that needs urgent systemic control. Each case is individual. In oncology, the small print mattersand unfortunately, the small print is often written by the cancer itself.

What Research Says So Far

Research on PIPAC has grown rapidly over the past decade, especially in Europe and Asia, and more U.S. centers have begun studying it through clinical trials. Current evidence suggests that PIPAC is technically feasible and may be safe in selected patients when performed by trained teams. Early U.S. phase I trials have evaluated PIPAC using drugs such as oxaliplatin for colorectal and appendix cancer, as well as cisplatin and doxorubicin for ovarian cancer with peritoneal metastases.

However, much of the available evidence remains early-stage. Phase I trials are primarily designed to evaluate safety, dosing, and feasibility, not to prove that a treatment improves survival compared with standard care. Some studies show encouraging signs of local tumor response or disease stabilization, but larger randomized trials are needed to determine which patients benefit most, which drug combinations work best, and how PIPAC should be integrated with systemic chemotherapy, immunotherapy, targeted therapy, surgery, or HIPEC.

The most responsible summary is this: PIPAC is promising, but still evolving. It is not a universal solution, and it should not be marketed as a guaranteed breakthrough. In medicine, “promising” is a good wordbut it is not the same as “proven for everyone.”

Questions Patients Should Ask About PIPAC

If you or a loved one is exploring PIPAC, bring a written list of questions to the oncology appointment. Good questions include:

• Is my cancer mainly limited to the peritoneal cavity?
• Am I a candidate for cytoreductive surgery or HIPEC?
• Is PIPAC available as standard care here or only through a clinical trial?
• What chemotherapy drug would be used?
• How many PIPAC cycles are planned?
• Will I continue systemic chemotherapy?
• What side effects should I expect?
• What signs would mean the treatment is working?
• What happens if PIPAC does not help?
• How experienced is this center with PIPAC?

These questions can help transform a confusing treatment discussion into a clearer plan. No patient should feel pressured into a procedure they do not understand. Cancer is stressful enough; the treatment vocabulary does not need to behave like a runaway spelling bee.

Experience-Based Insights: What the PIPAC Journey Can Feel Like

For many patients, the most emotional part of learning about PIPAC is not the science. It is the moment they hear, “You may not be a candidate for major surgery, but there may be another option.” That sentence can carry hope, fear, relief, and uncertainty all at once. PIPAC often enters the conversation after standard treatments have become difficult, less effective, or too toxic. By then, patients and families may already feel like they have collected enough medical vocabulary to fill a very depressing crossword puzzle.

One common experience is cautious optimism. Patients may appreciate that PIPAC is minimally invasive compared with open surgery. The idea of two small incisions, a shorter hospital stay, and a repeatable treatment can feel less intimidating than a long operation. At the same time, many people are surprised to learn that PIPAC is still frequently considered investigational or available through clinical trials in the United States. That can create a mix of hope and hesitation. Patients want innovation, but they also want evidence. Both instincts are wise.

Preparation for PIPAC often feels similar to preparing for other laparoscopic procedures. Patients may have blood tests, imaging, anesthesia evaluation, medication review, and detailed consent discussions. The care team may explain that the first laparoscopy is not only treatment but also an assessment. Sometimes, surgeons discover that PIPAC cannot be safely performed because of adhesions, bowel obstruction risk, or limited space in the abdomen. That possibility can be emotionally difficult, which is why honest pre-procedure counseling matters.

After the procedure, patients may experience soreness, bloating, fatigue, or nausea. Some feel surprisingly well within a few days, while others need more time. Recovery depends on overall health, cancer burden, nutrition, prior treatments, and whether the patient is also receiving systemic chemotherapy. Families often play a major role by tracking symptoms, managing appointments, organizing medications, and making sure the patient eats something more nourishing than crackers and heroic optimism.

The repeated-cycle nature of PIPAC can also affect emotions. Every treatment may bring new scans, biopsies, tumor-marker checks, and waiting periods. This creates a rhythm familiar to many cancer patients: treatment, recovery, scan anxiety, results, repeat. Some patients find comfort in having a plan. Others feel worn down by uncertainty. Supportive care, nutrition counseling, palliative care, social work, and mental health resources can be just as important as the procedure itself.

For caregivers, PIPAC can be both hopeful and confusing. Because it is specialized, families may need to travel to a cancer center, coordinate insurance questions, and understand trial eligibility. The best experience usually comes when the team communicates clearly: what PIPAC can do, what it cannot do, what side effects matter, and when to call urgently. Good care is not only advanced technology; it is also a nurse who explains the plan in plain English and a doctor who welcomes questions.

The practical takeaway is simple: PIPAC may offer a meaningful option for selected patients with peritoneal metastases, especially when standard choices are limited. But it works best as part of a larger treatment strategy, not as a stand-alone miracle. Patients should seek evaluation at experienced centers, ask about clinical trials, and make decisions with a team that understands both the science and the human side of advanced cancer care.

Conclusion

PIPAC, or pressurized intraperitoneal aerosolized chemotherapy, is one of the most interesting developments in regional cancer therapy for peritoneal metastases. By delivering chemotherapy directly into the abdomen as a pressurized mist, it aims to improve local drug distribution while reducing some of the burden associated with major surgery or full-dose systemic chemotherapy.

Still, PIPAC is not a cure-all. It is most often considered for carefully selected patients, frequently in a palliative or clinical-trial setting. The future of PIPAC will depend on stronger evidence, better patient selection, refined drug combinations, and thoughtful integration with systemic treatments. For now, it offers something valuable: another carefully studied path forward for patients facing one of the most difficult patterns of abdominal cancer spread.