A trial of chemotherapy and bevacizumab before surgery for rectal cancer (BACCHUS)

Cancer type:

Bowel (colorectal) cancer

Rectal cancer

Status:

Results

Phase:

Phase 3

This trial was for people whose rectal cancer had grown into surrounding tissue but hadn’t spread elsewhere in the body.

Cancer Research UK supported this trial.

This trial was open for people to join between 2013 and 2015. The team published the results in 2018.

More about this trial

Cancer that starts in the back passage (rectum) is rectal cancer. You might have radiotherapy to treat it. Or you might have a combination of chemotherapy and radiotherapy (chemoradiotherapy) before surgery.

Doctors can’t give as much chemotherapy with radiotherapy as they could if you have chemotherapy on its own. This is because of the side effects.

Researchers thought that having a targeted drug Open a glossary item instead of radiotherapy might be better at stopping the cancer coming back. In this trial they looked at a targeted drug called bevacizumab. It blocks a protein and stops the cancer from growing blood vessels. This starves the cancer and it can't grow.

The 2 combinations of chemotherapy used in the trial were:

FOLFOX
FOLFOXIRI – also known as FOLFIRINOX

These are standard treatments Open a glossary item .

The main aims of the trial were to:

see how well treatment worked to shrink the cancer before surgery
learn more about the side effects

Summary of results

The trial team said it was difficult to draw firm conclusions from these results as the trial had to close early.

The team found that the treatments didn’t shrink the cancer as much as they hoped. But the side effects of treatment were manageable.

Trial design
This was a phase 2 trial. The team had hoped to find about 60 people to take part. But only 20 people joined. This was because it was difficult to find enough people to join the trial.

They were put into 1 of 2 groups at random:

10 had fluorouracil (5FU), folinic acid and oxaliplatin (FOLFOX) and bevacizumab
10 had 5FU, folinic acid, oxaliplatin and irinotecan (FOLFOXIRI) and bevacizumab

bacchus.png

They had treatment once every 2 weeks for up to 12 weeks.

17 people completed their treatment. And 18 went on to have their surgery as planned to remove their rectal cancer. They had surgery between 6 and 8 weeks after finishing treatment.

Results
The researchers analysed the results of the people who took part. They looked at how well treatment had worked. To do this they examined the tissue removed during surgery to see whose cancer had gone away completely. A specialist doctor called a pathologist Open a glossary item did this analysis.

They found that cancer had gone away completely in 2 people who had FOLFOXIRI and bevacizumab. But this didn’t happen to anyone who had FOLFOX and bevacizumab.

At 2 years they looked at the number of people living. This is overall survival.
They found this was:

all of the people who had FOLFOXIRI and bevacizumab
most of the people (80%) who had FOLFOX and bevacizumab

They also looked at the number of people living whose cancer hadn’t started to grow again. This is progression free survival. They found this was:

all of the people who had FOLFOXIRI and bevacizumab
more than half of the people (60%) who had FOLFOX and bevacizumab

Side effects
This was a small trial. A few people who had FOLFOX and bevacizumab had severe side effects. These included:

heart problems
tummy pain
constipation or diarrhoea
being sick
an increased risk of infection
kidney problems
high blood pressure

A few people who had FOLFOXIRI and bevacizumab had severe side effects. These included:

a drop in the number of blood cells in the bone marrow
tummy pain
tiredness (fatigue)
infection or an increased risk of infection
a drop in the level of salt in the blood
high or low blood pressure

The team found that treatment didn’t increase the number of complications from surgery. Only 1 person developed a wound infection.

Conclusion
It was difficult to reach definite conclusions about treatment as the trial had to close early. This was because it was difficult to find enough people to take part.

Despite this the researchers think that the combination of FOLFOXIRI and bevacizumab could be promising. They hope to test this combination of treatment in future trials.

All trial results help doctors and researchers understand more about different cancers and the best way to treat them.

Where this information comes from
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) 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.