Plasma Analysis for Response Assessment and to DIrect the manaGement of Metastatic Prostate Cancer

In the UK, prostate cancer is the most common cancer in men and with about 1 in 8 men diagnosed with prostate cancer in their lifetime. Up to a third of prostate cancer deaths occur when cancer spreads to other parts of the body known as metastatic prostate cancer, which is a major healthcare burden. Currently, physicians use a maximum of six cycles of Docetaxel and continue Androgen Receptor Signalling Inhibitor (ARSI) drugs until disease progression with long term androgen deprivation therapy (ADT). There is no early test to indicate if treatment is working for patients with metastatic prostate cancer. Currently Prostate Specific Antigen (PSA) is not sensitive enough to guide treatment alone. Studies in colorectal, lung and prostate cancers have started looking at substance called Plasma tumour deoxyribonucleic acid (ptDNA) and correlated presence of ptDNA will early relapse. Therefore, this study will investigate if the detection of ptDNA after initiating treatment is associated a worse clinical outcome. Our ultimate aim, is to identify which of the current treatment options will work best for patients in the future. This research may also identify new targets for the development of new drugs to test in clinical trials in the future. Assessments will include blood taken before and during treatment and at cancer progression. In selected centres, an optional Whole Body Magnetic Resonance Imaging (WBMRI) will be performed before and during treatment for those patients who are eligible. Patients will be followed up for a maximum of 10 years at the time they register onto the study. We expect recruitment duration to be 18 months.