Abstract P6-02-11: When needles are needed
Authors: von Euler-Chelpin M , Vejborg I , Lænkholm A-V , Guleria S , Peterkin A , Lynge E 
Published: May 2016

Abstract
Background
Women with positive screening mammograms but negative at assessment (false-positive) are referred back to routine screening assuming that they have an average risk of breast cancer. However in a long-term follow-up of women with false-positive screening mammography we found that these women had in fact an excess risk of breast cancer later in life; RR=1.67(von Euler-Chelpin et al, JNCI 2012). This finding has later been supported by Castells et al.(Cancer Epidemiol, 2013). Furthermore, we studied the breast cancer cases in false-positive women and found that 26% of the cases were misclassified and were in fact true positives. However, even correction for misclassification, the false-positive women in our study remained at an excess breast cancer risk. At the same time, it was clear that, in the later periods of our study, when more modern techniques were used, the rate of misclassification decreased (von Euler-Chelpin et al, Cancer Epidemiol., 2014).
Over time there have been changes both in the imaging and biopsy techniques. We used data from an organised screening programme in Denmark. Since its start in 1991, needle biopsies have been performed on all palpable solid lesions and on all uncertain, suspicious or malignant findings. In the very beginning fine needle aspiration cytology (FNAC) was used, later to be replaced by needle core biopsies in the majority of cases. Since 2002, suspicious micro-calcifications and impalpable mammographic findings not found by ultrasound have been examined using stereotactic needle core biopsy and later with vacuum-assisted breast biopsy as a replacement for surgical biopsy.
To have a needle breast biopsy taken is a psychological burden on the woman. To minimize the harms and maximize the benefits is at the core of developing medical care. We therefore mapped the use of needle biopsies over time in a long-standing, organised screening programme.
Method: We used data from the population-based screening mammography program in Copenhagen, Denmark. The programme has a database including personal records on demographic data, date of invitation, data of screening, and test results,1998-2013. Data from the Mammography Register were linked to the Danish Pathology Register (for biopsy procedures).
Results: A total of 208 500 screens were included in the study. The rate of recall for assessment ranged between 1.7-3.2% of screened women with a mean of 2.4. The false-positive rate ranged between 1.0-2.5% with a mean of 1.6%. In 1998, 56% of all recalled women had a biopsy taken, which by 2013 had risen to 74% (using two-year smoothing). In proportion of all screens, the biopsy rate was 1.9% in 1998/99 which then fell to 0.7% in 2005/06 and the rose again 2.0% in 2012/13. In 1998, 59% of the biopsies were fine-needle aspiration cytology (FNAC) which by 2013 was only used in 11% of the cases, and replaced by core biopsies, ultrasound or stereotactic guided.
Conclusion
While the recall rate, as well as the false-positive rate, has been fairly stable during the study period the use of needle core biopsies has had a u-shaped development and has intensified in the later years.
Citation Format: von Euler-Chelpin M, Vejborg I, Lænkholm A-V, Guleria S, Peterkin A, Lynge E. When needles are needed. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-02-11.