A nuclear imaging technique that makes prostate cancer cells visible on scans could significantly reduce the number of men undergoing unnecessary biopsies, according to results from the PRIMARY2 clinical trial presented at the European Association of Urology Congress 2026 in London.
The technique, known as PSMA PET/CT imaging, uses a tracer molecule that binds to prostate cancer cells. When scanned, these cells appear as bright spots, allowing clinicians to detect potentially aggressive tumours with greater precision. Researchers found that incorporating the scan into the diagnostic pathway after MRI could reduce the number of prostate biopsies by around 50 percent without missing clinically significant cancers.
A more targeted diagnostic pathway
Men with suspected prostate cancer typically undergo MRI to identify abnormal areas in the prostate. When results are suspicious or inconclusive, a biopsy is usually performed to confirm the presence of cancer. While routine, biopsies are invasive procedures that can cause discomfort and carry potential side effects.
The PRIMARY2 trial focused on patients at increased risk of prostate cancer, such as those with a strong family history, who had reassuring MRI results but would often still proceed to biopsy.
In the study, participants were randomly assigned to receive either a standard biopsy or a PSMA PET/CT scan. Patients with negative or low-risk findings on the scan did not undergo biopsy, while those with positive results proceeded to targeted tissue sampling. According to the researchers, this approach halved the number of biopsies performed while maintaining accurate detection of harmful cancers.
Improving precision and reducing overtreatment
For patients who still required biopsy, the scan helped identify specific suspicious areas, allowing clinicians to perform more targeted procedures. This may reduce complications and improve diagnostic accuracy. PSMA PET/CT imaging has already been used in many countries for diagnosing high-risk or recurrent prostate cancer, although access and cost still limit widespread adoption in parts of Europe and the UK. The technology is more widely available in Australia.
Dr. James Buteau, nuclear medicine physician at the Peter MacCallum Cancer Centre, said the technology could play a key role in addressing overdiagnosis in prostate cancer. “PSMA PET/CT scanning makes prostate cancer cells light up in a remarkable way, particularly in more aggressive cancers,” he said. “Incorporating this testing into clinical care could help to address the major challenge of prostate cancer overdiagnosis.”
Large international study
The PRIMARY2 trial is a Phase III study conducted across Australia, led by researchers from the Peter MacCallum Cancer Centre and St Vincent's Hospital Sydney. In total, 660 participants are being followed for two years to evaluate long-term outcomes.
According to Professor Louise Emmett, director of Theranostics and Nuclear Medicine at St Vincent’s Hospital Sydney and co-leader of the study, the approach may provide greater reassurance for patients. “Our findings show that PSMA PET/CT after MRI offers a ‘belt and braces’ approach that can determine which people have a clinically significant cancer, and which people are at low risk and don’t need a biopsy or further testing,” she said.
Independent experts also welcomed the results. Professor Derya Tilki, senior consultant urologist at the Martini-Klinik Prostate Cancer Center, noted that the study demonstrated the potential of PSMA PET/CT to reduce unnecessary biopsies without compromising the detection of clinically relevant disease. “These results support consideration of PSMA PET/CT in the diagnostic work-up of appropriately selected patients,” she said.
If confirmed in further follow-up analyses, the findings could help refine prostate cancer diagnostic pathways and reduce the burden of invasive procedures for patients.
