Researchers at the Charité hospital in Berlin have used state-of-the-art equipment to reduce prostate biopsies in men who were unlikely to develop harmful prostate cancers.
The criteria for early diagnosis of prostate cancer could change, limiting the use of biopsies to a select few patients, and relying on the results of a special MRI scan for all others (as is done in women under 40 for breast cancer).
A study published in the scientific journal JAMA Oncology by researchers at the Charité university hospital in Berlin, Germany, has shown that a sophisticated MRI scan is capable of predicting whether or not a patient needs a biopsy, with a high level of reliability. Based on data collected over an eight-year period, the findings show that the invasive procedure can be avoided in the vast majority of cases, relying on regular check-ups instead.
After the age of 50, men are often advised to have a prostate specific antigen (PSA) test. While elevated levels of this protein can be a sign of cancer, they can also indicate benign conditions, such as a simple inflammatory enlargement. If the blood test shows high PSA levels, a biopsy is recommended, which is considered essential in order to check the characteristics of the prostate tissue. However, this means taking 10-12 samples with a series of needles through the rectum or perineum – a painful procedure that causes unpleasant side effects over the following days and increases the risk of infection. Also, the sampling is done “blind”, which means there is a high chance of finding slow-growing cancers that would never have carried any risks anyway but that are still treated aggressively.
Charlie Hamm, lead author of the study published in JAMA Oncology explained: “These side effects of systematic biopsies urged us to find out if MRI is reliable and safe for biopsy decision-making in men with suspected prostate cancer, and if men without abnormal MRI findings can safely skip immediate biopsy and enter clinical follow-up.”
Sophisticated equipment for prostate cancer detection
The team monitored 593 patients aged 18 to 75, with suspected prostate cancer, for high levels of PSA and other markers. All the subjects had a multiparametric magnetic resonance imaging (mpMRI) scan at Charité. This type of MRI scan allows multiple parameters to be assessed at once, such as type of prostate tissue, blood flow in the area, diffusion of water molecules in the region and other factors that distinguish healthy tissue from diseased tissue.
“Tissue samples were taken only if the MRI showed suspicious findings in the prostate,” continued Dr Hamm. "Patients with normal MRI findings underwent regular urological check-ups for three years instead. That allowed us to see whether the ‘MRI pathway’ is safe.”
The researchers found that 96% of patients with a normal MRI result didn’t go on to develop an aggressive prostate cancer in the three years that followed. Harmful cancers were detected during further monitoring in only 4% of participants whose initial MRI results had been negative. The study continued for a further five years in the end, for a total duration of eight years.
So, according to the researchers, even if MRI scans don’t identify every single at-risk case, they make it possible to exclude the vast majority of cases that would otherwise have been investigated unnecessarily. What’s more, if combined with a system of regular check-ups (including further PSA tests and MRI scans and testing of any other parameters), an MRI scan may be sufficient as a method of early diagnosis.
Expert radiologists needed
The European Association of Urology (EAU) guidelines recommend that an MRI scan be performed before a prostate biopsy. However, the guidelines don’t clearly specify if and when biopsy should be “skipped”, say the researchers at Charité. The study published in JAMA Oncology now casts new light on the matter.
But there are two essential conditions: the results must be interpreted by expert radiologists with specific training in this type of test, and the healthcare system must organise a safety net, calling patients in for regular urological visits over a period of at least three years. The German oncologists say that if these two crucial aspects are observed, MRI could replace biopsy in the guidelines in the years to come, avoiding the need for pointless – and often harmful – investigations and treatments in a considerable number of people.
