Researchers have examined whether a magnetic resonance imaging (MRI)-first approach is safe for prostate cancer detection over the long term, according to a recent study published by Hamm et al in JAMA Oncology.
Background
Several strategies may be deployed for the early detection of prostate cancer. The first step is often a prostate-specific antigen (PSA) test that measures the levels of this protein in the blood. PSA levels exceeding a certain threshold could indicate the presence of prostate cancer and typically necessitates taking a tissue sample for analysis. However, elevated levels can also result from noncancerous conditions. Traditionally, elevated PSA levels have led to a punch biopsy, where 10 to 12 tissue samples are taken systematically from the prostate. This procedure is associated with side effects for several days and can carry a 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.
The second option is to use MRI to search for signs of a tumor prior to deciding whether a biopsy is necessary. This strategy reserves biopsies only for cases in which abnormalities are detected.
“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,” said lead study author Charlie Hamm, MD, PhD, a physician in the Department of Radiology at the Charité–Universitätsmedizin Berlin and a junior digital clinician scientist at the Berlin Institute of Health at Charité.
Study Methods and Results
In the recent study, the researchers assessed the safety of the MRI-first strategy, in which normal MRI findings were followed by regular urologic checks, among nearly 600 patients with suspected prostate cancer. The participants underwent multiparametric MRI, which is capable of detecting multiple tissue-specific parameters such as 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 then interpreted the images. The study was completed after 8 years.
“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 3 years instead. That allowed us to see whether the MRI pathway is safe,” Dr. Hamm detailed.
The researchers discovered that the MRI-first approach may be sufficiently reliable and pose no additional risk among patients for at least 3 years. They found that 96% of the patients with a normal MRI result did not go on to develop aggressive prostate cancer within 3 years. Aggressive prostate cancer was detected during further monitoring in just 4% of the patients, 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 [suspicious] cancer findings,” emphasized Dr. Hamm. “Normal MRI findings alone do not offer 100% 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,” he continued.
Conclusions
“Our findings are an important step toward personalized care of [patients with] prostate cancer. By using MRI for biopsy decision-making, we can ensure that patients receive the right tests and treatments at the right time,” Dr. Hamm underscored.
The researchers indicated that the results of the study may also be relevant for physicians when it comes to supporting their patients in deciding when a biopsy is needed. 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. 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,” added Dr. Hamm.
Two other aspects may be crucial if the new findings are incorporated into practice in the near future, according to the researchers. A high-quality MRI scan must be performed and analyzed by experienced experts. This may require training more radiologists in the detailed and accurate interpretation of prostate MRI scans and using standardized methods. It may also be critical 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 concluded.
Disclosure: The research in this study was funded by the 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. For full disclosures of the study authors, visit jamanetwork.com.
