A study looking at how the microbiome affects breast cancer treatment (NEO-MICROBE BREAST Study)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Breast cancer





This study is to see if gut bacteria (the microbiome Open a glossary item) affects how well chemotherapy works before surgery for breast cancer. 

The study is for women:

More about this trial

Chemotherapy before surgery is a common treatment for breast cancer. Chemotherapy works better in some people than others. Researchers are looking for ways to try and find out why this happens. 

The natural bacteria that live in your mouth and gut is the microbiome. There are lots of bacteria in our gut. We know that they are important for keeping us healthy. We also know that diet can change this gut bacteria. 

The researchers hope to identify certain patterns in the bacteria that link with how well chemotherapy works. To do this they will look at:

  • blood samples
  • poo samples 
  • a sample of your cancer tissue

They will also try to understand if the microbiome affects who might get bad side effects from chemotherapy. 
In this study researchers are looking for people with breast cancer who are having chemotherapy before surgery. They are also looking for people who don’t have cancer. 

The main aim of this study is to find out whether the gut microbiome can predict:

  • how well chemotherapy works
  • who gets bad side effects 

Please note, you won’t get any direct benefit if you take part in the study. It might help other people with breast cancer in the future. 

Who can enter

The following bullet points are a summary of the entry conditions for this study. Talk to your doctor or the study team if you are unsure about any of these. They will be able to advise you. 

Who can take part

You may be able to join this study if all of the following apply. You:

  • are born female
  • have invasive breast cancer
  • have cancer that is HER2 positive Open a glossary item or you have triple negative breast cancer 
  • are due to have chemotherapy before surgery 
  • had a tissue sample taken from the breast when you were diagnosed 
  • can understand English well and don’t need to use an interpreter
  • are at least 16 years old

The study team are looking for healthy volunteers who are:

  • born female
  • at least 16 years old

Who can’t take part

You cannot join this study if any of these apply. You:

  • have cancer that has spread elsewhere in the body
  • have had another cancer in the last 2 years and you had treatment to the whole body (systemic treatment Open a glossary item). For example you had chemotherapy.
  • have a problem with your digestive system Open a glossary item such as ulcerative colitis, Crohn’s disease, irritable bowel syndrome (IBS) that is severe or you take regular medication or you have long term problems with diarrhoea or being sick 
  • have had major surgery to your digestive system. This doesn’t include having surgery to remove gallstones or your appendix.
  • have had treatment that damps down the immune system Open a glossary item within 1 month of starting chemotherapy. You may be able to take part if you had low dose steroid treatment. 
  • have a problem with how your immune system works. This includes having HIV, hepatitis B or a hepatitis C infection
  • have had COVID-19 within the last 28 days 
  • are pregnant and or breastfeeding 
  • have any other medical condition that isn’t well controlled or there is any other reason your doctor thinks would affect you taking part

Trial design

This study is taking place in Glasgow, Lanarkshire and Forth Valley.

The team need:

  • 75 people who have breast cancer  
  • 25 people who don’t have cancer

Taking part in this study will not affect your planned cancer treatment. 

Study samples
You give a poo sample:

  • before you start chemotherapy 
  • after you finish chemotherapy but before surgery 

The team give you kits to collect the poo samples at home. The kits include instructions on how to collect and store the samples. The team arrange a suitable time with you to deliver a mini freezer and/or special cool bag to your home. You store the samples in the freezer or cool bag until they are collected. 

A volunteer driver from Beatson Cancer Charity, a taxi driver, or a researcher collects the samples. Or you can drop them off at a pre arranged location. 

You also give a blood sample before you start chemotherapy. Where possible you give the sample at the same time as a routine blood sample. 

The team ask your permission to get a sample of cancer tissue (biopsy) Open a glossary item from when you were diagnosed.

The healthy volunteers give one poo sample. Healthy volunteers do not give any blood samples or need to complete any diet questionnaires.

You complete some questionnaires about your diet. You do this: 

  • before you start chemotherapy
  • after your last dose of chemotherapy 

These take about 20 to 30 minutes to fill in. You can do this either in the clinic or at home. 

Checking how you are getting on with treatment 
The team ask you about possible side effects of chemotherapy and other specific medications that you may have taken. You do this either on the day ward or a member of the team will call you. This takes about  5 to 10 minutes.

They also check your medical notes when you finish chemotherapy and again after surgery. They want to see how well your treatment worked.

Hospital visits

There are no extra hospital visits if you take part in this study.

Side effects

You may have a small bruise where you have your blood test. 

Your doctor and nurses monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better.

We have information about:

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Iain Macpherson

Supported by

Beatson Cancer Charity
Chief Scientist Office (CSO)
Experimental Cancer Medicine Centres (ECMC).
NHS Greater Glasgow and Clyde
Royal College of Physicians & Surgeons of Glasgow – Aileen Lynn Bequest Fund

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Last reviewed:

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