Can prostate cancer be diagnosed with near certainty on MRI?

We hypothesised that it was possible for radiologists to identify scans as positive for tumour with near certainty on MRI alone.

880 consecutive patients attended our clinic for suspected prostate cancer and underwent enhanced multiparametric MRI (with a mean PIQUAL 1 score of 3.6/5). Of these, 251 were scored Likert 4-5/5 on MRI and were the study group. 4 experienced radiologists retrospectively scored the 251 scans, knowing PSA and age, to one of three levels of certainty: '99% sure', '90% sure' and '< 90% sure'. If their scores were different then a consensus opinion was achieved by discussion. Histology was by targeted transperineal biopsy. Significant tumour was considered Gleason Grade Group (GG) 2 and above.

In consensus, 79 patients (9% of those presenting to the one stop clinic and 30% of patients scoring 4-5/5 on the MRI read at the time) were scored positive with a '99% sure' level of certainty. Of these, 69 were biopsied and all (100%) had significant tumour, with 72% Gleason GG3 or higher. 45 patients were scored positive to the '90% sure' level. Of these 41 underwent biopsy and 40 (98%) had significant tumour (the one negative patient had GG1 tumour). In the '< 90% sure group, 42% had significant tumour, of which only 7% was GG3 tumour or higher.

There is a group of patients in whom prostate cancer is close to certain based on MRI findings. In future this may enable treatment without the need for biopsy.