There are several strategies for the early detection of prostate cancer. The first step is often a blood test for prostate-specific antigen (PSA). If PSA levels exceed a certain threshold, the next step typically involves taking a tissue sample for analysis. Another option is to use magnetic resonance imaging (MRI) to search for signs of a tumor before deciding whether a biopsy is necessary, reserving biopsies only for cases where abnormalities are detected. Researchers at Charité — Universitätsmedizin Berlin conducted a study to determine whether this MRI-first approach is safe over the long term. Their findings show that this strategy poses no additional risk to patients for at least three years. The study has now been published in the journal JAMA Oncology.
The conventional approach to diagnosing prostate cancer includes clinical examination and prostate-specific antigen (PSA) testing. PSA testing measures the levels of this protein in the blood, which can be elevated in prostate cancer. However, elevated levels can also result from non-cancerous conditions. Traditionally, elevated PSA levels have led to a punch biopsy, where ten to 12 tissue samples are taken systematically from the prostate — a procedure that is associated with unpleasant side effects for several days afterward and carries a certain risk of infection. Additionally, PSA-driven “blind” biopsies often result in overdiagnosis of slow-growing, clinically insignificant cancers while risking the oversight of aggressive cancers.
“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,” says Dr. Charlie Hamm, the first author of the publication and a physician at the Department of Radiology at Charité who is also a Junior Digital Clinician Scientist at the Berlin Institute of Health at Charité (BIH).
No need for a biopsy with negative MRI findings
This approach, in which normal MRI findings are followed by regular urological checks, did in fact prove to be sufficiently reliable: The study found that 96 percent of patients with a normal MRI result would not go on to develop aggressive prostate cancer within three years. Aggressive prostate cancer was detected during further monitoring in just four percent of participants whose initial MRI findings had been negative.
“That means the cancer risk is very low when MRI scans of the prostate do not show any cancer suspicious findings,” says Dr. Hamm. “Normal MRI findings alone do not offer one hundred percent certainty, but with regular monitoring, potential cancer can still be detected early enough. For many patients, that means they can avoid the discomfort of a biopsy at first and do not need to worry about having cancer that will remain undetected.”
Monitoring is sufficient for early detection of cancer
The team included and monitored nearly 600 patients with suspected prostate cancer in their study. The subjects underwent multiparametric magnetic resonance imaging (mpMRI) at Charité. This type of MRI detects multiple tissue-specific parameters, including the signal intensity of the prostate tissue, the blood flow or perfusion, and the diffusion of water molecules in the tissue. A team of experienced radiologists interpreted the images. “Tissue samples were taken only if the MRI showed suspicious findings in the prostate. 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,” Dr. Hamm says, explaining the study design.
High-quality MRI findings and safety net are essential
The study has now been completed after eight years. “Our findings are an important step toward personalized care of prostate cancer patients. By using MRI for biopsy decision-making, we can ensure that patients receive the right tests and treatments at the right time,” Dr. Hamm says.
The results are also relevant for doctors when it comes to supporting their patients in deciding when a biopsy is really needed. The European Association of Urology (EAU) guidelines already recommend that an MRI should be performed before a prostate biopsy. However, it was previously unclear how safe it would be to skip the biopsy altogether in cases of negative MRI results. “Our results now show that the MRI pathway is safe and effective, including in a decentralized outpatient care network,” Dr. Hamm comments. “We hope the study will serve as impetus to further enhance the standing of MRI as an aid to deciding for or against a biopsy in the German guidelines, and elsewhere.”
However, the study’s authors say two other aspects are crucial if the new findings are to be incorporated into practice in the near term. First, a high-quality MRI scan must be performed and analyzed by experienced experts; that means training more radiologists in the detailed and accurate interpretation of prostate MRI scans and using standardized methods. Second, it is important to create a safety net for patients who do not undergo immediate biopsy. “That means clear guidelines for PSA testing, follow-up MRIs, and criteria for when a biopsy might be needed later on,” Dr. Hamm points out.
About the study
The study was performed in close cooperation between urologists in private practice in Berlin and the Department of Radiology at Charité. The external physicians were involved in the conceptual design of the study and in recruitment, patient monitoring, and treatment. Sources of funding for the study include local cancer association Berliner Krebsgesellschaft e.V., radiology association Berliner Röntgengesellschaft — Röntgenvereinigung zu Berlin und Brandenburg e.V., and urology association Berliner Urologische Gesellschaft e.V.
