Impact of a novel biopsy instrument with a 25-mm side-notch needle on the detection of prostate cancer in transrectal biopsy

Objectives: To evaluate the impact of a novel biopsy instrument that extends the length of the side-notch on the detection of prostate cancer in transrectal needle biopsy. Methods: We collaborated with a biopsy needle manufacturer and developed a novel biopsy instrument (PRIMECUT II long-notch type) with a 25-mm side-notch length and 28-mm stroke length to take longer tissue cores. The sampled core length, cancer detection rate, pain and complications of 489 patients who underwent transrectal biopsy using the long-notch needle were compared with those of 469 patients who underwent biopsy using a normal instrument with a 19-mm side-notch length and 22-mm stroke length. Results: The mean length of tissue taken by the long-notch needle was significantly longer than that of tissue taken by the normal-notch needle (16.3 vs 22.4 mm, P < 0.001). The overall cancer detection rate was 42.0% for the normal-notch needle and 51.1% for the long-notch needle (P = 0.005). In patients with a prostate volume of 20–40 mL, the cancer detection rate for the long-notch needle was especially higher than that for the normal-notch needle (74.2% vs 47.5%, P < 0.001). Multivariate analysis showed that the long-notch needle improved cancer detection significantly (odds ratio 1.702, P < 0.001). There were no differences of pain during biopsy and complication between the two groups. Conclusions: The novel biopsy instrument with a 25-mm side-notch can take longer tissue samples safely and has a significantly higher rate of prostate cancer detection in transrectal biopsy.