102 Quick summary: Israeli researchers have found that two simple biopsy measurements, the number of cancerous areas in the prostate and the length of the largest lesion, can predict aggressive prostate cancer more accurately than standard tools such as PSA levels, MRI score, and biopsy grade. Around 41% of patients in the study had more advanced disease after surgery than pre-operative assessments suggested, pointing to a significant gap in current risk stratification methods. Adding these measures to clinical decision-making could help doctors identify men who need surgery rather than active surveillance, reducing both undertreatment and overtreatment in a condition that affects large numbers of men worldwide. A new study from Israel has proposed a straightforward method to better identify men with prostate cancer who face a higher risk of aggressive disease before surgery. Researchers at Clalit-Soroka Medical Center suggest that counting the number of cancerous areas and measuring the length of the largest lesion in fusion biopsy samples can predict advanced cancer more effectively than some traditional tools. Prostate cancer is the most common malignant tumour among men. It develops in the prostate gland, a small organ located below the bladder that produces seminal fluid. Many cases progress slowly, allowing some men to live with the disease for years without symptoms. Diagnosis often follows raised prostate-specific antigen (PSA) levels or imaging tests. Certain cases turn aggressive and spread beyond the prostate, so distinguishing low-risk tumours suitable for monitoring from those needing prompt treatment is vital. The research, published in JU Open Plus, involved 131 men diagnosed with prostate cancer who had radical prostatectomy between 2020 and 2024. The team, led by Professor Nicola Mabjeesh, head of the Urology Department at Clalit-Soroka Medical Center, examined ways to enhance risk assessment beyond standard measures such as PSA levels, biopsy grade, and MRI score. They focused on two indicators: the number of prostate areas where cancer was detected, and the length of the largest cancer lesion found in fusion biopsy samples, a procedure combining MRI and ultrasound guidance. Professor Mabjeesh explained: “Today, prostate cancer is usually diagnosed following elevated PSA levels. In such cases, MRI is performed, followed by a targeted fusion biopsy when needed. Since we accompany patients from diagnosis through surgery, we were able to precisely examine the relationship between biopsy findings and what is ultimately found during surgery.” Results showed that around 41% of patients had more advanced disease after surgery than originally estimated. This included cancer that had spread beyond the prostate, reached the seminal vesicles, or involved surgical margins. Standard measures such as PSA, MRI score, and biopsy grade did not significantly predict which patients had more advanced disease, whereas both new indicators did, even after adjusting for other factors. The researchers identified practical cutoffs to guide clinical decisions. Patients with more than three cancer-positive areas, or a cancer lesion longer than 10 mm, had a higher likelihood of advanced disease at surgery. Prof. Mabjeesh said: “Today, in many cases, the decision whether to monitor or operate is based mainly on tumour grade. For example, when the disease is grade 1, the tendency is to choose active surveillance. We suggest adding another layer: if there are more than three affected areas, surgery should be considered rather than surveillance alone.” He added that the information may also help when choosing between surgery and radiation therapy, since it may indicate the disease is more extensive than it first appears. Asked whether some patients appeared low risk on paper but were actually higher risk, Professor Mabjeesh replied: “Absolutely. That is the central point of the study. There are patients who appear low risk based on PSA, tumour grade, or MRI, but in reality, they have broader cancer involvement.” Using these indicators could avoid overtreatment in roughly four out of 100 patients based on lesion count and around 10 out of 100 based on lesion length. The authors stressed this was a retrospective single-centre study with a relatively small patient group, and that larger multicentre studies are needed before widespread use. Professor Mabjeesh said: “The next step is larger-scale studies, preferably multicentre, that will test the criteria we identified and allow structured implementation in daily practice.” He added: “I believe this metric could eventually be included in future guidelines. In the past, we have already published work that entered European guidelines.”