A trial looking at chemotherapy and cetuximab for advanced bowel cancer (E-SCOUT)

The researchers published their results in 2015. They found that chemotherapy and cetuximab is a useful treatment for advanced bowel cancer. People coped with treatment better after the dose of cetuximab was reduced. 

The researchers also found that it might be possible to use circulating tumour cells (CTCs) to decide who should have intensive treatment and who should not. 

48 people took part in this phase 2 trial. All patients had treatment with cetuximab, oxaliplatin, irinotecan and UFT. It was possible to measure the response to the treatment in 44 of the 48 people. Out of the 44:

• the cancer had completely disappeared (complete response) in 2 people
• the cancer had shrunk (partial response) in 29 people
• the cancer stayed the same (was stable) in 12 people 
• the cancer continued to grow in 1 person 

At the start of the trial everyone had bowel cancer that was inoperable. Following chemotherapy and cetuximab the cancer in 5 people had shrunk enough to allow an operation.

• 4 people had surgery to remove their bowel cancer
• 1 person had surgery to remove cancer that had spread to the liver (liver secondaries or metastases)

On average people taking part in the trial lived for about 22 months.

The researchers also looked at the side effects of the treatment. The most common side effects people had included: 

• a drop in white blood cells causing an increased risk of infection
• diarrhoea
• tiredness (fatigue)

The first 8 patients experienced severe diarrhoea. The doctors thought this was due to using cetuximab alongside the chemotherapy. So the dose of cetuximab was reduced for the rest of the patients taking part and fewer people reported diarrhoea as a problem.

The number of people who had numbness and tingling in the hands and feet (peripheral neuropathy) was low and no one experienced hair loss. The researchers think this was due to patients having irinotecan one month and oxaliplatin the next month.

Circulating tumour cells 
The researchers were able to measure circulating tumour cells (CTCs) in 42 people. The level of CTCs were categorised as low or high.

• 22 patients had a high level of CTCs
• 20 patients had a low level of CTCs

The researchers looked at the length of time that each group lived and compared these with the results of another trial for advanced bowel cancer called CAIR02. This CAIR02 trial followed patients who had less intensive treatment, but it still included chemotherapy and a monoclonal antibody. These patients were also categorised as having either a low level or high level of CTCs. 

For patients with low CTCs, no difference was found in survival between the E-SCOUT and CAIR02 trial. In the group with high CTCs, there was a difference in survival between people in the E-SCOUT trial and the other trial. Those patients with high levels of CTCs in E-SCOUT lived for longer than expected, suggesting they benefitted from intensive treatment using the 4 different drugs. 

Those in the group with low CTCs did not seem to gain an extra benefit from their treatment. This suggests that intensive treatment like this may not be useful and could be avoided, along with the side effects.

We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed ) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.