British scientists said the technique, which picks up circulating cancer cells in a patient’s blood, could be available on the NHS in as little as three years. Prostate cancer is the most common cancer among British men, with 47,000 diagnoses a year. Currently, men with possible signs of the disease are offered a test which looks for elevated levels of a protein called PSA.
If high levels are detected, a tissue biopsy of the prostate gland has to be taken to confirm disease. But no tumour will be found for around three quarters of men undergoing the invasive procedure. In many other cases, disease is found, with men undergoing gruelling treatment, despite the fact the tumour was growing so slowly that it would not have proved deadly. The new test is able to identify the most aggressive cases, which require treatment, with accuracy of more than 90 per cent, when combined with PSA results.
Scientists from Queen Mary University of London said it could help men avoid unnecessary and invasive biopsies, over-diagnosis and over-treatment. The test – called Parsortix – detects early cancer cells, or circulating tumour cells (CTCs), that have left the tumour and entered the bloodstream. This appears to be more accurate than measuring PSA proteins, which can be present in the blood for reasons other than cancer. The study, published in the Journal of Urology, looked at the use of the CTC test in 98 pre-biopsy patients and 155 newly diagnosed prostate cancer patients enrolled at St Bartholomew’s Hospital in London.
Researchers found that the presence of CTCs in pre-biopsy blood samples correctly determined which patients had cancer. The number and type of CTCs also helped indicate how aggressive the cancer was.
Lead researcher Professor Yong-Jie Lu, from Queen Mary University of London, said: “The current prostate cancer test often leads to unnecessary invasive biopsies and over-diagnosis and over-treatment of many men, causing significant harm to patients and a waste of valuable healthcare resources. There is clearly a need for better selection of patients to undergo the biopsy procedure. Testing for circulating tumour cells is efficient, non-invasive and potentially accurate, and we’ve now demonstrated its potential to improve the current standard of care.
“By combining the new CTC analysis with the current PSA test, we were able to detect prostate cancer with the highest level of accuracy ever seen in any biomarker test, which could spare many patients unnecessary biopsies. This could lead to a paradigm shift in the way we diagnose prostate cancer.”
Dr David Montgomery, director of research at Prostate Cancer UK said the findings were interesting, calling for larger trials. He said: “The study is small but seems to demonstrate that testing for these cells could help better predict which men are likely to have clinically significant prostate cancer and should go for further investigation.” He said it was crucial that in the short term, all men with suspected prostate cancer are offered specialist scans, before a diagnosis is made.