'Prostatic evasive anterior tumours': the role of magnetic resonance imaging

To review our experience and delineate the role of magnetic resonance imaging (MRI) in identifying patients presenting with a raised prostate-specific antigen (PSA) level and clinical findings suggestive of anterior predominant tumours, which appear to be significant, particularly in those with a previous negative biopsy or low-volume disease undergoing active surveillance.

We retrospectively reviewed our database to identify patients with anteriorly predominant tumours on MRI whom had undergone prostate biopsy.

In all, 31 patients with anterior predominant tumours on MRI also had a positive biopsy (14 on active surveillance and 17 with previous negative biopsies). MRI was usually invoked by the presenting PSA level or PSA velocity. MRI had a positive predictive value for anterior tumours of 87% (27/31). The Gleason score distribution for the 27 men with cancer was 6 in 15; 3 + 4 in three, 4 + 3 in six and 8/9 in three. For prostatic cores, 44/85 (52%) samples from the anterior prostate had cancer. Thirteen patients had a radical prostatectomy (pT2 in three, pT3 in seven and pT4 in three); seven of the 13 had positive surgical margins and a third of them had a biochemical recurrence at the 1-year follow-up.

There is a subset of patients either having a negative biopsy or low-volume disease and who are on active surveillance who should be considered for MRI and further biopsy, as their pathology might be aggressive. An entity might be emerging with anterior predominant tumours that are impalpable, and we believe the term 'prostate evasive anterior tumour syndrome' to be appropriate. This requires further analysis in a large prospective database with consideration for triggers for MRI and targeted biopsies.