The PICCOS clinical trial is investigating an innovative way of delivering chemotherapy for people living with cancer that has spread to the peritoneum, the thin layer of tissue lining the abdomen and covering the organs inside it.

Peritoneal cancer can either begin in the peritoneum itself, known as primary peritoneal cancer, or spread there from another organ, referred to as secondary peritoneal cancer. This type of spread is most commonly associated with colorectal, ovarian, stomach, and appendiceal cancers.

For many patients, standard chemotherapy remains an important treatment option. However, when chemotherapy stops working, the cancer progresses, or the disease returns, treatment choices can become more limited. PICCOS aims to explore whether a different way of delivering chemotherapy directly into the abdomen could improve outcomes and quality of life for some patients.

What Is PIPAC?

The trial focuses on a technique called Pressurised Intraperitoneal Aerosol Chemotherapy (PIPAC).

Unlike standard chemotherapy, which is usually delivered through a vein or as tablets, PIPAC delivers chemotherapy directly into the abdominal cavity as a fine pressurised aerosol during keyhole surgery under general anaesthetic.

Researchers hope this targeted approach may allow chemotherapy to spread more evenly across the peritoneal surfaces and penetrate tumour tissue more effectively, while potentially reducing exposure to the rest of the body.

Who Can Take Part?

PICCOS is open to adults aged 16 and over whose cancer has spread to the peritoneum from:

• Colorectal cancer
• Ovarian or fallopian tube cancer
• Gastric cancer
• Appendiceal cancer

The trial is also open to people with primary peritoneal cancer that has returned or progressed despite platinum-based chemotherapy.

To be considered for the trial, participants must also meet several medical criteria, including having visible peritoneal lesions on a CT scan and being well enough to undergo chemotherapy and keyhole surgery.

Anyone interested in taking part should speak with their oncologist, who can assess eligibility and advise whether a participating trial centre may be suitable.

How Does the Trial Work?

Participants who join the study will be randomly assigned to one of two groups.

One group will receive standard chemotherapy for their cancer type. Treatment schedules and medications will vary depending on the individual situation and will be discussed with the treating oncology team.

The second group will receive PIPAC treatment. Participants may undergo up to three PIPAC procedures, each performed approximately six weeks apart during laparoscopic surgery under general anaesthetic.

Before each procedure, participants will undergo routine assessments, including blood tests, physical examinations, and, in some cases, heart monitoring, to ensure they are fit for treatment. Follow-up calls and ongoing monitoring will also help researchers understand recovery, side effects, and overall well-being.

What Is the Trial Aiming to Learn?

The PICCOS study aims to better understand:

• How effective PIPAC is compared with standard chemotherapy
• What side effects may occur and how manageable they are
• How treatment affects quality of life, symptoms, and day-to-day functioning

Participants in both groups will undergo additional follow-up assessments, including CT scans, blood tests, and quality of life questionnaires, helping researchers build a clearer picture of the potential benefits and risks of this approach.

Clinical trials such as PICCOS are essential for advancing cancer care and exploring new treatment possibilities for patients facing difficult diagnoses. Through research and innovation, studies like this aim to improve future care and expand options for people living with peritoneal disease.

Author:

Rebecca Hamilton PICCOS Trial Team, Centre for Trials Research, Cardiff University