Scientists establish new blood test to better evaluate prostate cancer

An international study led by researchers at The Institute of Cancer Research will pave the way for a test to be used to better tailor treatments and hopefully extend the survival of men with aggressive forms of metastatic prostate cancer. 

The study, to be published tomorrow in Cancer Clinical Research has found that this analysis of Circulating Tumour Cells (CTC) can be utilised to study the prognosis of prostate cancer and is an independent indicator for overall survival of the disease.

Lead researcher Dr Johann de Bono at The Institute of Cancer Research and The Royal Marsden Hospital says: “CTC testing, used in conjunction with the existing prostate specific antigen (PSA) test, may allow doctors to more accurately evaluate the effect of treatment on a patient’s tumour.” “These studies are a very promising development, allowing cancer cells to be detected using a simple blood test and may eventually allow us to tailor cancer treatments to maximise the benefit for patients. Hopefully this will lead to improving the survival of patients with metastatic prostate cancer.” 

The PSA test has been widely adopted as the benchmark test for prostate cancer in the UK, but it is not always possible to identify a clear relationship between a raised PSA level and the status of the disease. Circulating tumour cells (CTCs) are cancer cells that have broken away from an existing tumour and have entered into the bloodstream. The presence of these cells in the blood provides valuable insights into disease progression. This study has shown that the monitoring and detection of CTCs can provide valuable information on the patient’s prognosis. Further studies are taking place to evaluate if the CTC test may be used to allow doctors to make treatment decisions more quickly and more reliably for the benefit of patients. 

The test has already been incorporated into several prostate cancer drug trials that are taking place at The Institute and The Royal Marsden. The test has been cleared by the FDA in the United States to determine the prognosis of patients with metastatic breast, colorectal or prostate cancer. The study was in partnership with the New-York based Memorial Sloan-Kettering Institute and involved 231 patients undergoing chemotherapy treatment. Sixty-five clinical centres in Europe and the U.S. took part in the study. The patients underwent monthly CTC monitoring to measure the level of circulating tumour cells in the blood. A count of more than 5 CTC per 7.5 ml of blood was seen as an indicator towards an “unfavourable” prognosis whereas a count of less than 5 CTC per 7.5ml was considered “favourable”. This was compared with the progression of the metastatic prostate cancer tumours.