They hope their work will allow doctors to switch patients to alternative treatments earlier than is currently possible, if these results are confirmed by further studies. The research could also hasten the development of cancer treatments by speeding up clinical trials, since doctors could tell much earlier whether a treatment is working.
The study was led in the UK by researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, and also involved several leading international institutions. It was funded by a range of organisations including a Medical Research Council biomarkers grant, the companies Janssen Diagnostics, the Prostate Cancer Foundation in the US, and Prostate Cancer UK.
As tumours grow and progress, they shed cancer cells into the bloodstream, some of which can seed new secondary tumours elsewhere in the body. So the researchers wanted to see whether a high number of circulating tumours cells was an indication of a growing tumour that wasn't responding to treatment, and could predict a lower chance of survival.