Improving glandular coverage during prostate biopsy using a long-core needle: technical performance of an end-cutting needle.

Abstract

OBJECTIVE: To compare the technical performance of a 33-mm core-length biopsy needle with that of the standard 18 mm needle, as many prostate cancers are isoechoic and in large prostates the tissue coverage with the 18 mm needle is inadequate. PATIENTS AND METHODS: A 33-mm core length BioPince VSL disposable needle (Amedic, Sweden) and a standard TruCut 18 mm needle (Medical Device Technology Inc., FL, USA) were used to take prostatic biopsies in two groups of 15 patients. The following variables were assessed for each group: mean core length, core quality, capsular coverage (one or both capsules within the specimen), and side-effects in the first week after biopsy (for the BioPince group, surveyed using a self-completed questionnaire). The results were compared with historical data from a group of 30 patients biopsied using the standard needle. RESULTS: For the BioPince and standard groups the mean (sd) core length was 19.4 (8.9) and 14.9 (5.1) mm, respectively. Four needles in the BioPince group failed to capture a sample, requiring needle replacement. The samples were fragmented in 15 of 90 (17%) and 41 of 90 (46%) biopsies in the BioPince and standard groups, respectively (P < 0.05). Specimens had both capsules present in five of 90 (6%) and four of 90 (4%), respectively. Within 7 days minor bleeding was the most common side-effect. Pain after biopsy was the only symptom showing a significant difference between the groups, at six of 15 and none (P = 0.001), respectively. The incidence of haematuria, haematospermia and rectal bleeding was similar in the two groups (P > 0.05), but fever more common (three vs none) in the BioPince group (P = 0.06). CONCLUSION: When set at a 33-mm stroke length, the BioPince needle increases the mean core length by 30%, with less fragmentation than a standard 18 mm needle. However, it has a significant failure rate for capture (27% needle replacement rate), slightly greater morbidity (pain and possibly fever) and shows no advantage in capsular coverage. Therefore, there are shortcomings with this end-cutting needle when used at 33 mm core length.