Percutaneous Ultrasound-Guided Core Needle Biopsy: Comparison of 16-Gauge versus 14-Gauge Needle and the Effect of Coaxial Guidance in 1065 Breast Biopsies - A Prospective Randomized Clinical Noninferiority Trial.

Purpose:  Ultrasound-guided core needle biopsy (CNB) is considered the standard assessment to diagnose sonographically visible suspicious breast mass lesions. Based on nonrandomized trials, the current German guidelines recommend at least three cylinders with ≤ 14-gauge needle biopsy. However, no recommendation is made as to how many specimens are needed with a smaller needle size, such as 16-gauge, or if biopsy with coaxial guidance improves diagnostic accuracy and quality. Therefore, in a prospective monocentric unblinded randomized controlled clinical noninferiority trial, the diagnostic accuracy of 16-gauge versus 14-gauge core needle biopsy, with and without coaxial guidance, was evaluated.

Materials And Methods:  1065 breast biopsies were included in order to analyze the number of core samples necessary to obtain an appropriate rate of diagnostic quality adequate for histological evaluation, and to achieve high diagnostic accuracy and diagnostic yield. Histological results were verified by surgery or long-term follow-up of at least two years up to five years.

Results:  In order to obtain an additive diagnostic accuracy of > 99 %, a minimum of two cylinders with 14-gauge biopsy were required. The diagnostic accuracy and the diagnostic quality of 14-gauge biopsy were not affected by the coaxial technique. When performing a 16-gauge biopsy, five cylinders were required to achieve an additive diagnostic accuracy of > 99 %. Without coaxial guidance, 16-gauge CNB required at least three samples, whereas five needle passes with coaxial-guided 16-gauge biopsy were needed.

Conclusion:  The diagnostic accuracy and quality of ultrasound-guided 16-gauge core needle biopsy were inferior to the 14-gauge needle size, regardless of the use of a coaxial technique.