Predictors of Clip Migration Status and Distance Following Stereotactic Breast Biopsy

Purpose: Stereotactic vacuum-assisted biopsy (ST VAB) is a minimally invasive diagnostic tool to evaluate abnormal findings identified on breast mammography. Upon biopsy completion, a clip marker is deployed in the cavity for site identification. Thus, clip migration poses clinical challenges that undermine the purpose of biopsy markers. This study aimed to investigate factors contributing to clip migration in ST VAB.

Methods/Materials: A retrospective review of patients who underwent ST VAB within an integrated healthcare system from 2022 to 2025 was performed. Prebiopsy, intraprocedural, and post-biopsy mammograms were reviewed to assess for clip migration. Multivariable Generalized Estimating Equations (GEE) models identified predictors of migration status and distance, accounting for clustering by radiologist–technician teams. GEE logistic regression models evaluated whether clip migration occurred, and among those with migration, GEE linear regression models assessed log-transformed migration distance. Statistical significance was set at p < 0.05.

Results: Of the 769 biopsies analyzed, clip migration was observed in 202 (26.3%; range, 0.5–6.0 cm). There were statistically increased clip migrations in biopsies for microcalcifications (p = 0.019), at posterior depth (p = 0.010), within the upper outer quadrant (p = 0.042), and at closer proximity to the skin (p = 0.023). No significant association was seen with patient age, breast density, biopsy approach, clip marker type, and number of cores taken. However, among subjects that did demonstrate clip migration, greater migration distance was associated with asymmetry or architectural distortion (p = 0.024), Hydromark clips (p = 0.008), and within the upper outer quadrant (p < 0.001).

Conclusions: Clip marker placement after ST VAB is crucial for accurate site identification, and clip migration can pose significant clinical challenges. Our study suggest that the biopsied lesion characteristics, location, and clip type influence the likelihood and magnitude of clip migration following ST VAB. Understanding the interaction of these modifiable factors with different breast morphologies may help reduce clip migration.