A study looking at DNA and tissue damage in men having radiotherapy for prostate cancer

Cancer type:

Prostate cancer

Status:

Results

Phase:

Other

This study was done to see if there was a link between DNA damage and side effects of radiotherapy for prostate cancer.

It was open for people to join between 2011 and 2017, and the team published the results in 2017.

More about this trial

Radiotherapy kills cancer cells by damaging the genetic code (DNA) inside the cell. But it can also damage healthy cells close to the area being treated.

Radiotherapy for prostate cancer can cause bowel or bladder related side effects, because they are so close to the prostate gland. It can cause short term side effects soon after treatment. It can also cause some long term side effects, months or years later.

Researchers wanted to find out more about DNA damage and repair after radiotherapy. They measured the amount of specific proteins that increase if the DNA in cells is damaged.

They also assessed the side effects people had after treatment. They wanted to see if there was a link between this and the DNA damage caused by radiotherapy.

The main aim of the study was to find out more about DNA damage caused by radiotherapy. And to see if this is linked to the side effects people have.

Summary of results

The research team found that the amount of DNA damage after radiotherapy could be linked to long term side effects of the bowel.

Study design
Everyone taking part in this study was due to have a type of radiotherapy called brachytherapy for prostate cancer.

The research team took blood samples before people had treatment, and then at:

1 hour, 4 hours and 24 hours
1 month and 3 months

The research team measured the amount of 2 proteins in the blood samples. These are called gamma H2AX (ɣH2AX) and 53BP1. They are released into the blood when DNA is damaged. So an increase in these proteins would suggest there has been DNA damage within cells.

The people taking part completed a quality of life questionnaire before treatment, and then at:

1 month, 3 months, 6 months and 9 months
1 year, 2 years and 3 years

These questionnaires asked about the side effects people were having.

Results
12 people with prostate cancer took part in this study. They all had brachytherapy radiotherapy.

The research team found that the amount of cell damage increased most quickly in the first 24 hours after treatment. But that it continued to rise, up to 4 weeks after treatment. This was a bit longer than they were expecting.

The team found that there was a link between:

the amount of gamma H2AX and 53BP1 proteins in blood samples 24 hours after treatment, and
the bowel related side effects people had 1 year and 2 years after treatment

They also found that people who had a higher dose of radiotherapy had more long term side effects.

The research team noted that only a small number of people took part in this study. They would need to do more research with a larger number of people to be sure of these results.

Conclusion
The research team concluded that there could be a link between the amount of DNA damage 24 hours after prostate brachytherapy, and long term bowel side effects. They suggest further work is done with more people to find out more about this.

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.