PIPAC – a clinical trial looking into a new type of treatment for advanced bowel cancer

Consultant Colorectal Surgeon Jamie Murphy tells us about a clinical trial looking at a new type of treatment – PIPAC – for patients who have bowel cancer that has spread to the peritoneum. Dr Murphy gives us an overview of what this new treatment is, who it's suitable for and how people can take part in the clinical trial.

What is PIPAC?

PIPAC stands for Pressurised IntraPeritoneal Aerosolised Chemotherapy. We are studying PIPAC as part of a clinical trial to see if it can shrink secondary cancers growing on the inside lining of the abdominal cavity (known as the peritoneum). These tumours are known as peritoneal metastases.

PIPAC is a type of chemotherapy given directly into a patient's abdomen (tummy) during an operation. After PIPAC is given it stays inside the abdomen for 30 minutes, with the whole operation taking around two hours.

PIPAC operations are repeated every 6-8 weeks. There are only a small number of studies about PIPAC currently available, but we expect each patient will have two-three PIPAC operations on average. It's not usually a treatment used on its own, so most patients continue to take their normal chemotherapy too. Practically this usually means that patients have two cycles of normal chemotherapy between each PIPAC operation.

What is HIPEC and how is PIPAC different?

HIPEC stands for Hyperthermic Intraperitoneal Chemotherapy. PIPAC and HIPEC operations have different purposes – PIPAC is not a replacement for HIPEC surgery. The aim of a HIPEC operation is to remove as much of the cancer as possible and then destroy any cancers cells that can't be seen with the naked eye by putting hot chemotherapy inside the abdomen.

Not all patients can have a HIPEC operation. One of the main reasons for this is some patients have too many tumours in their peritoneum. This is where PIPAC comes into play – the aim of the PIPAC operation is to get control of the cancer by shrinking the number and size of the tumours in the peritoneum. For some patients these tumours may shrink enough to mean that a HIPEC operation becomes possible in the future.

Who can take part in trial?

Our trial is recruiting two groups of patients. The first group are those who have only ever been treated using one type of chemotherapy drug (referred to as 'first line chemotherapy'). These drugs must have stopped the tumours in the peritoneum from growing for six months or more.

The second group of patients are those who have switched to a second type of chemotherapy drug (known as 'second line chemotherapy'). Patients in this group can be considered for PIPAC surgery at anytime during their treatment.

At the moment patients can only have this type of treatment as part of a clinical trial. As part of the trial, currently the only hospitals in the UK offering PIPAC are Imperial College London and University Hospital of Wales. Our team and colleagues in Cardiff are the first to introduce PIPAC to the UK. Patients who wish to be considered for PIPAC need to be referred by their GP or Oncologist to: jamie.murphy2@nhs.net (Imperial) or kathryn.hearne@wales.nhs.uk (Wales). Imperial College London and University Hospital of Wales are also trying to help set up PIPAC centres around the UK.

Why can't all bowel cancer patients have this treatment?

PIPAC won't work for everyone. For example, patients who have had major surgery may have too much scar tissue inside for the treatment to be possible. Other patients might have a large number of secondary cancers outside the abdomen – PIPAC doesn't treat these cancers so it's unlikely to improve their quality of life or life expectancy. These potential issues do vary widely between different patients and do not always prevent PIPAC being performed successfully. Your doctor will be able to tell you if PIPAC might be suitable for you.

What does taking part in the trial involve?

Patients who take part in the trial will need to have several operations for PIPAC chemotherapy to be delivered. Patients will also be asked to complete quality of life questionnaires during treatment to assess any side effects and the impact PIPAC is having on their symptoms. Extra CT scans are also needed to see how well it's working.

What are the benefits and the risks?

The potential benefit of PIPAC is that it may shrink the size and number of tumours in the peritoneum, but at the moment there's not enough research to tell for sure how effective PIPAC is for bowel cancer.

We don't think that PIPAC and normal chemotherapy alone will be able to cure people of their peritoneal metastases. The research so far suggests it could mean tumours in the peritoneum might shrink – for some patients this might then mean they can then have HIPEC treatment.

Like all treatments there are risks with PIPAC – although rare, these could include potentially having to have a larger operation or having a reaction to the chemotherapy drug. Before you have PIPAC treatment your doctor will explain all the potential risks with you. Because of the uncertain benefits and the potential risks of PIPAC, we have introduced it to the UK in the form of a trial to study this treatment in more detail.

When will this treatment be widely available in the NHS?

All new treatments in the UK have to be assessed by the National Institute for Health and Care Excellence (NICE) before they can be offered to patients. PIPAC has not yet been assessed by NICE. It will be several years before there is enough evidence assessing how effective PIPAC is in bowel cancer patients. Only then will it be decided if PIPAC should be more widely available in the UK outside trials like ours.

• Find out more about the PIPAC trial
• Find out more about clinical trials
• Read more about bowel cancer that has spread to the peritoneum.