Abstract P2-02-03: Impact of genetic testing for hereditary breast cancer on supplemental breast imaging and false positive biopsy rates among young breast cancer patients
Authors: Ro Vicky , Zhao Ziyi , Pan Samuel , Crew Katherine D. 
Published: March 2020

Abstract
Introduction Annual mammography screening is recommended for women diagnosed with breast cancer for the early detection of local recurrence and new breast primaries. Younger women have higher breast density, which lowers the sensitivity of mammography for early detection. The American Cancer Society recommends breast MRI as an adjunct to mammography for women with known hereditary breast cancer syndromes. However, there is insufficient evidence on the use of breast MRI or ultrasound as an adjunct to screening mammography among young women with a personal history of breast cancer. Our objective was to investigate factors associated with use of supplemental screening among young breast cancer patients and the impact of supplemental screening on detection of breast cancer recurrence and false positive biopsy rates. Methods We conducted a retrospective analysis of women diagnosed with stage 0-III breast cancer at age 50 years or younger at Columbia University Irving Medical Center in New York, NY between 2007 and 2017. Patients were excluded if they had stage IV disease at diagnosis, bilateral mastectomy, or no breast imaging available in the CUIMC electronic health record (EHR). All clinical data was extracted from the EHR and tumor registry, including receipt and results of genetic testing. Supplemental screening was defined as use of breast ultrasound or MRI in the absence of breast symptoms and in the setting of a normal mammogram. Breast cancer recurrence and false positive biopsy were defined as any breast biopsy which did or did not show ductal carcinoma in situ (DCIS) or invasive carcinoma, respectively. Univariate and multivariate analyses were performed to assess the association between demographic and clinical factors and our main outcomes of supplemental screening and false positive biopsy. Results Among 681 evaluable women, mean age at diagnosis was 44 years (SD, 4.9) with 41.6% white, 28.2% Hispanic, 12.6% black, 11.7% Asian, and 5.9% other race/ethnicity. About 62.7% had private insurance and 23.1% Medicaid, and 47% had undergone genetic testing, including 20 (2.9%) with pathogenic variants. Over half (51%) had supplemental screening with either breast MRI or ultrasound, 130 (19.1%) had a false positive biopsy, and 52 (7.6%) had a breast cancer recurrence, with about half (51.9%) screen-detected. In multivariate analysis, supplemental screening was less likely among black and Hispanic women compared to whites (odds [OR]=0.56, 95% confidence interval [CI]=0.33-0.97 and OR=0.46, 95% CI=0.30-0.72, respectively), those with Medicaid compared to private insurance (OR=0.46, 95% CI=0.30-0.71), and women with lower breast density (OR=0.63, 95% CI=0.43-0.92). False positive biopsies were more frequent among women who underwent supplemental screening compared to those who did not (26.4% vs. 11.4%, p&lt;0.001), however, screen-detected breast cancer recurrences were comparable (4.0% vs. 3.9%, p=0.209). Supplemental screening was associated with a greater than 2-fold increased risk of false positive biopsy (OR=2.77, 95% CI=1.78-4.32). Compared to young breast cancer patients who did not undergo genetic testing, women with pathogenic variants had a trend toward more supplemental screening (OR=2.28, 95% CI=0.82-6.36) and more false positive biopsies (OR=2.75, 95% CI=0.96-7.85). Conclusions Our findings suggest that decisions to engage in supplemental screening are influenced by insurance coverage and breast density. Furthermore, patients who receive supplemental screening were significantly more likely to have false positive biopsies, but had no difference in screen-detected breast cancer recurrences. Prospective studies are needed to better define optimal screening strategies for young breast cancer survivors.
Citation Format: Vicky Ro, Ziyi Zhao, Samuel Pan, Katherine D. Crew. Impact of genetic testing for hereditary breast cancer on supplemental breast imaging and false positive biopsy rates among young breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-02-03.