An exploratory analysis of the PROMIS and PICTURE trials from Imperial College London has been published in European Urology Oncology. The study examined the significance of prostate cancer lesions that are not visible on MRI but occur alongside an MRI-detected lesion.

A total of 306 patients with one or two suspicious quadrants on MRI were included; 5-mm transperineal template mapping biopsy served as the reference standard. In 14 per cent of patients, an additional MRI-undetected lesion was present alongside the MRI-detected cancer. These were consistently of lower Grade Group and smaller size (median maximum cancer core length 2 mm versus 6 mm).

Of 127 patients considered eligible for focal therapy on the basis of MRI-targeted biopsy alone, whole gland biopsy would not have changed the treatment template in 91 per cent; in 8.7 per cent a larger ablation area would have been required, or eligibility would have lapsed. Adding systematic biopsy of the contralateral hemigland identified all of these cases – equivalent to twelve additional biopsies per corrected treatment plan.

The authors conclude that MRI-targeted biopsy alone was sufficient both for detecting Grade Group 2–5 and Grade Group 3–5 cancer and, in the majority of patients, for planning focal therapy. This gains relevance as urological practice moves towards MRI-targeted and peri-lesional biopsies alone.

At the same time, they emphasise the exploratory nature of the analysis; prospective validation is still required.

Accurate delineation and transfer of the MRI-visible lesion therefore gains further weight, in fusion biopsy as much as in subsequent treatment planning.

Read more in European Urology Oncology, doi:10.1016/j.euo.2026.05.018