Scientists are trialling a new blood test that may be available on the NHS in the future to help screen patients with aggressive prostate cancer.
Prostate cancer is the most common cancer among British men. It affects one in eight but many men have a low grade or benign form of the cancer which may not need treatment at all and/or can be left untreated for decades.
If a patient is suspected by their GP of having prostate cancer following a blood test to look for elevated levels of the protein PSA (prostate specific antigen), they should be referred for further investigations which (depending on the local trust to which the patient is referred) may involve an invasive biopsy of the prostate. A raised PSA does not, however, mean that prostate cancer is present. It may be elevated for other reasons, such as a urinary infection or prostatitis (swelling of the prostate). Therefore many men are subjected to an invasive prostate biopsy when cancer is not present at all. Alternatively, the result of the biopsy may be positive but the cancer may, in fact, be low grade and capable of being monitored without further invasive treatment. However, to avoid under-diagnosis, many men in this situation are advised to undergo radical surgery to remove the cancer (known as a prostatectomy) and suffer common side effects such as urinary incontinence and/or impotence. If it could be shown that the cancer was not aggressive, then those patients may have avoided the surgery and the side effects altogether.
Unlike breast cancer, there is not yet a formal screening programme to determine whether prostate cancer is present and, if so, whether it is an aggressive or benign form. The PSA blood test is useful in helping a GP decide whether further investigations are required, but it is not an appropriate screening tool for determining whether prostate cancer is present. The big question, therefore, is whether it is possible to identify those patients who have cancer which is not likely ever to proceed to treatment from those patients who have an aggressive form of cancer that needs treating urgently.
This may soon change. The new blood test that has been created searches for live cancer cells in the blood and is 90% accurate for determining whether the patient has an aggressive form of the cancer. If this is confirmed, then the patient will be referred for urgent treatment. If the blood test is negative, then the patient will likely be reviewed regularly to monitor any progression of their low-grade cancer and appropriate steps to treat the cancer can then be taken when it is shown to have progressed. Scientists from Queen Mary University of London behind the new test believe that it could help men to avoid unnecessary biopsies, over-diagnosis and over-treatment.
The blood test could be available in private practice within 18 months and, all being well, could be available to the NHS in three years. For now, however, the steps to diagnosis are clear. Any man with suspected prostate cancer following an elevated PSA blood test should be referred for further investigations. A high-quality MRI scan is the current gold standard for diagnosing prostate cancer in the UK, however this diagnostic tool is not available in all NHS trusts and some men will continue to undergo a biopsy of the prostate.
Arran Macleod, a solicitor in the clinical negligence team at Penningtons Manches Cooper LLP, welcomed this development, saying: “We act for many patients with prostate cancer. Some of our clients have undergone invasive treatment for their benign prostate cancer, suffering terrible side effects such as incontinence and impotence. Others have aggressive cancer that should have been diagnosed sooner than it was and suffer the tragic consequence of a shortened life expectancy.
“We consider it a positive step forward if this new blood test can act as a method for screening which patients have aggressive cancer that needs treatment from those with benign cancer that is not likely to progress and hope that it leads to a formal prostate cancer screening programme in the NHS. We will continue to monitor developments in this area with interest.”
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