2213 RESULTS OF MRI TARGETED, VISUALLY REGISTERED, TRANS-RECTAL ULTRASOUND GUIDED PROSTATE BIOPSY

Abstract

INTRODUCTION AND OBJECTIVES: With increasing interest in MRI for the detection and localisation of prostate cancer, we examine the use of TRUSS biopsies visually targeted to MR abnormalities in our institution. METHODS: 100 consecutive men who underwent prostate MRI, followed by a standard and then visually targeted TRUSS biopsy were identified from the departmental TRUSS biopsy database. Total and clinically significant cancer detection rates were compared between standard and targeted cores. Clinical significance was set at 3mm of any cancer, or any Gleason pattern 4. RESULTS: 100 men (mean age 64, range 44 87; mean PSA 10.1, range 1.4 76.7) were identified between February 2010 and May 2011. 1112 standard cores were taken (mean 11, range 6 12 per patient) by experienced radiologists following a protocol determined by prostate volume. Additionally, 183 visually targeted biopsies were taken (mean 1.8, range 1-4 per patient) from areas of suspicion identified on MRI. 10 men had clinically significant cancers detected on standard biopsy that were missed by targeted biopsy. All were Gleason 3 4 with a mean maximum cancer core length of 5.9mm. 4 men with clinically significant cancers detected on targeted biopsy were missed by standard biopsy. 11 clinically insignificant cancers detected by standard biopsy were missed by targeted biopsy. The number of cores taken per cancer diagnosis (sampling efficiency) was 20 for standard cores or 4.5 for targeted cores. CONCLUSIONS: Targeted biopsies are of interest in the detection of clinically significant prostate cancer. We assessed the use of visually registered USS guided biopsies directed at MR abnormalities in this retrospective cohort. Of concern is 17 men with significant cancer on standard biopsy were classified as benign (10 men) or with insignificant disease (7 men) on targeted biopsy. This may be due to inherent flaws in visual registration. These rates may be improved by the introduction of computerised MRI to US registration techniques.