In a new study, researchers found a new and simple blood test could efficiently and accurately detect the presence of aggressive prostate cancer.
In combination with the current prostate specific antigen (PSA) test, the new test could help men avoid unnecessary and invasive biopsies, over-diagnosis and over-treatment.
The research was conducted by a team from the Queen Mary University of London.
Prostate cancer is the most common cancer in Western men, with 1.3 million new cases being diagnosed each year worldwide.
It is currently detected using a blood test that measures PSA levels.
Although it provides early diagnosis, the PSA blood test has low specificity (high false positives) with about 75% of all PSA positive results ending up with negative biopsies that do not find cancer.
When a high PSA level in the blood is detected, the patient undergoes a tissue biopsy of the prostate gland, which is invasive and carries a significant risk of bleeding and infection.
On biopsy, the majority of patients with elevated PSA levels are found not to have cancer.
Additionally, most diagnosed early-stage prostate cancers are not fatal if left untreated.
The current practice of the combined PSA test and biopsy for prostate cancer, therefore, results in unnecessary biopsies and over-diagnosis and over-treatment of many men.
The new prostate cancer test (the Parsortix system from ANGLE plc) detects early cancer cells or circulating tumor cells (CTCs), that have left the original tumor and entered the bloodstream prior to spreading around the body.
By measuring intact living cancer cells in the patient’s blood, rather than the PSA protein which may be present in the blood for reasons other than cancer, it potentially provides a more accurate test for prostate cancer.
In the study, the team 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.
They found that the presence of CTCs in pre-biopsy blood samples were indicative of the presence of aggressive prostate cancer, and efficiently and non-invasively predicted the later outcome of biopsy results.
When the CTC tests were used in combination with the current PSA test, it was able to predict the presence of aggressive prostate cancer in subsequent biopsies with over 90% accuracy, better than any previously reported biomarkers.
Additionally, the number and type of CTCs present in the blood were also indicative of the aggressiveness of cancer.
The team says focusing on more aggressive prostate cancer may reduce overtreatment and unnecessary biopsies for benign and non-aggressive conditions.
As this is a single center study, the results need to be further validated in other independent research centers before the CTC test is available either privately or on the NHS in the UK, which could take a further 3-5 years.
Clearance by the US Food and Drug Administration could also take 3-5 years.
The lead author of the study is Professor Yong-Jie Lu from the Queen Mary University of London.
The study is published in the Journal of Urology.
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