A study looking at developing a test to see how well chemotherapy is working for breast cancer (Neo-DDRD)

Study design
This study was for women who had early stage breast cancer. This is breast cancer that hasn’t spread further than the breast. 

46 women took part. They either had a combination of chemotherapy called FEC or they had FEC followed by another chemotherapy drug called docetaxel. 

FEC included the drugs:

• fluorouracil (5FU)
• epirubicin 
• cyclophosphamide

Some women also had a targeted cancer drug called trastuzumab if suitable. 

The team looked at tissue samples. These were taken:

• at diagnosis 
• when chemotherapy started
• 3 months after starting chemotherapy 

The team analysed the samples using the DDRD (DDIR) test. The test looked at changes in the cells that could tell them how sensitive to chemotherapy the cancer cells would be. They also looked at tissue samples from surgery. This was to see how well chemotherapy had worked. 

Results
The team looked at the DDRD test results. This was the test that might predict how well chemotherapy would work. They found:

• 26 people had cancer that was DDRD positive. This means that chemotherapy is likely to work. 
• 20 people had cancer that was DDRD negative. This means that chemotherapy isn’t likely to work. 

The team also found that the results of the DDRD test were available within 14 days for nearly everyone who took part.

The team then checked how well treatment had actually worked. To do this, they examined tissue samples taken at surgery. The team compared the predictions with how well treatment did work, to see if there was a link. 

Of the 26 people who were DDRD positive, they found:

• 14 (54%) had cancer that went away completely or a little bit
• 12 (46%) had a moderate number of cancer cells or a lot of cancer cells left behind

Of the 20 people who were DDRD negative, they found:

• 4 (20%) had cancer that went away completely or a little bit
• 16 (80%) had a moderate number of cancer cells or a lot of cancer cells left behind

Conclusions
The study team think that the results show that the DDRD test may be useful to predict who chemotherapy will work best for. The test might also help to identify who could benefit most from a type of chemotherapy called an anthracycline. 

This was a small study. The team suggest that more work is done to confirm these findings.

More detailed information
There is more information about this research in the reference below. 

Please note, this article is not in plain English. It has been written for health care professionals and researchers.

Journal articles
Activation of a cGAS-STING-mediated immune response predicts response to neoadjuvant chemotherapy in early breast cancer
E Parkes and others 
British Journal of Cancer, 2022. 126, pages 247–258 

Where this information comes from    
We have based this summary on the information in the article above. This his has been reviewed by independent specialists (peer reviewed ) and published in a medical journal. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the article is free and available to view.