The BBC reported this week on a new blood test which has been developed to help with prostate cancer treatment.
A study found a blood test could detect who men new drug treatment. Researchers analysed blood samples from nearly 50 men with advanced prostate cancer who were taking a new trial drug (olaparib).
They wanted to determine whether changes to tumour DNA in blood could show if olaparib treatment was working or not.
They found that
- Tumour DNA halved after four weeks of treatment in men who had the best progression-free survival.
- The development of new gene mutations in men who initially responded to olaparib, can indicate when the tumour was becoming resistant to the drug and the treatment was no longer working.
This work suggests that a blood test which looks at tumour DNA early enough in the course of olaparib treatment, may show for which men the treatment is working and which men would be better off trying an alternative treatment.
Who did this work?
This study was carried out by scientists at the UK Institute of Cancer Research, the Royal Marsden NHS Foundation Trust, the University of Michigan, and the Peter MacCallum Cancer Centre.
Funding was provided by several sources, including the Movember Foundation, the Prostate Cancer Foundation, Prostate Cancer UK, and Cancer Research UK.
About the olaparib study
- The study included only 50 men..
- All the men in the study had metastatic prostate cancer
- None of the men in the study had responded to previous hormone treatment and chemotherapy.
- All the men in the study were treated with the new drug olaparib.
Blood samples were collected from the trial participants at the start of the study, then after 1, 4, 8 and 16 weeks of treatment, and at the time when the disease had progressed.
The scientists analysed the circulating DNA in blood samples and looked at how the DNA changes were associated with specific responses.
There was a large (over 50%) reduction in circulating DNA concentration, measured by blood tests, which was associated with improved progression-free survival by four weeks and overall survival by eight weeks.
The scientists concluded that their findings support the role of a new blood test as a predictive, prognostic, response, and resistance biomarker in metastatic prostate cancer.
The findings also suggest that a decrease in circulating tumour DNA could suggest treatment is working.
Although these findings show promise, this study only looked at blood samples taken from a small sample of men. Therefore the study cannot say, at this stage, whether levels of circulating DNA have significance on disease outcome.
Towards the future
Although these findings need to be followed up by more studies of other men receiving olaparib for advanced prostate cancer. The results do suggest that if a test were developed, this could allow treatment to be changed at an early stage if blood results indicate treatment isn’t working.
This could hopefully help men with advanced stage disease have the best quality of life by making sure they only receive treatment likely to bring benefits.
The findings are a promising step forward in helping men with advanced prostate cancer receive the best treatment for them.
Circulating Free DNA to Guide Prostate Cancer Treatment with PARP Inhibition Cancer Discovery, June 19th 2017
New blood test could see personalised prostate cancer treatment. Guardian online, June 19 2017
Prostate cancer blood tests ‘helps target treatment’. BBC News, June 19 2017