Jacky Luiten

Utility of diagnostic breast excision biopsies during two decades of screening mammography | 37 3 The available diagnostic biopsy procedures include fine needle aspiration (FNA) cytology, or histologic analysis, carried out by either core needle biopsy (14‐18 Gauge), vacuum assisted needle biopsy (9‐11 Gauge) or excision biopsy. In this study we focused on excision biopsies. Excision biopsies ‐ primary biopsy method or secondary to percutaneous core needle biopsies, in case of persistent uncertainty (secondary excision biopsies) ‐ were analyzed separately, assuming that the trends in use could differ. Screening and follow up data of all recalled women were collected in a database kept up to date by one of the screening radiologists (LD). Statistical analysis The main outcome of this study was the incidence of the use of excision biopsies, where we especially focused on the difference between primary and secondary excision biopsies and the proportion of benign and malignant excision biopsy outcomes. Statistical analyses were performed using SPSS, version 24.0 (SPSS, Inc., Chicago, USA). The mean differences with standard deviation (SD) were calculated for continuous variables. Trends over time and variations between subgroups were expressed using proportions and percentiles. 95% confidence intervals (95% CI) and chi‐square analyses were performed to compare proportional differences between categorical groups and Fischer Exact Test was employed when sample sizes were small, causing the expected values to be smaller than ten. P ‐values less than 0.05 were considered statistically significant. Results Excision biopsy over time An excision biopsy was carried out in 908 recalled women (4.9% of recalls), which decreased from 214 (39.9%; 1997‐1998) to 84 (2.3%; 2015‐2016; p <0.001). The overall excision biopsy rate was 1.1 per 1000 screened women. This rate initially decreased from 4.4 in 1997‐1998 to 0.4 per 1000 screens in 2005‐2006 ( p <0.001) and subsequently increased again to 0.6 per 1000 screens in 2015‐2016 ( p =0.04, Figure 3.1).