A Variable Length Biopsy Device Designed for Improved Prostate Cancer Detection vs the Standard Biopsy Device: Pathological Comparisons and Needle Length Requirements for Men Undergoing Transperineal Biopsy

Purpose: To investigate a novel prostate biopsy device capable of taking specimens between 1.5 and 5.5 cm in length and to determine the distances from apex to base in men undergoing transperineal biopsy. Materials and Methods: An actuator was developed capable of firing an 18-gauge true-cut biopsy needle with a specimen notch of 5.5 cm adjustable at 1 mm between 1.5 and 5.5 cm. The length of specimens retrieved vs the notch length was determined using fresh porcine kidneys and compared with a Bard device. The distance from prostate apex to base was determined in men undergoing transperineal biopsy using a proprietary software program. The program determined apex to base lengths throughout the gland. The number of needles required to span the prostate between ≤ 2.0 cm to > 5.0 cm was also determined. Results: The variable length device outperformed the Bard device at different lengths collecting an average of 88% vs 82% of the notch length (n = 576, P < .001). The mean biopsy needle length required for an average prostate volume of 48.2 cc was 3.4 cm. 79.6% of the biopsies taken with the Bard device would not have reached that distance. The new needle collected 5.8 mm 3 of tissue vs 3.8 mm 3 (1.5 times more) for the Bard device. Conclusions: The variable length biopsy device can sample the prostate to 5.5 cm in length with an average of 88% of the specimen collected. Eighty percent of men would need a biopsy needle longer than what is typically used in clinical practice.