Abstract PD10-01: Trends in genetic testing and results for women diagnosed with breast cancer or ovarian cancer, 2013-2017

Abstract

Abstract Background: Genetic testing is increasingly important for breast and ovarian cancer risk reduction and treatment. However, little is known about trends and disparities in receipt of testing in the community and test results after diagnosis. Methods: We linked records of all women with breast cancer or ovarian cancer diagnosed from 2013-2017 in Georgia and California and reported to Surveillance, Epidemiology and End Results (SEER) registries to genetic testing results from four laboratories that did most clinical testing in the studied regions (Ambry Genetics, GeneDx, Invitae, Myriad Genetics). We combined test results performed by all laboratories over 2012-2019 with SEER data. We measured use of any test, median number of genes tested, rates of variants of uncertain significance (VUS) and pathogenic variants (PVs). Results: A total of 25.2% of 187,535 breast cancer patients, and 34.3% of 14,689 ovarian cancer patients, had genetic testing. Testing increased annually by 2% while the median number of genes tested increased annually by 28%. Among tested patients diagnosed with breast cancer in 2017, 5.2% had BRCA1/2 PVs while 4.9% had PVs in genes associated with a recognized cancer syndrome (APC, CDH1, MLH1, MSH2, MSH6, NF1, PMS2, PTEN, RET and TP53) or with emerging evidence for an increased risk of breast cancer and/or ovarian cancer (ATM, BARD1, BRIP1, CHEK2, NBN, PALB2, RAD51C and RAD51D). Among tested patients diagnosed with ovarian cancer in 2017, 11.0% had BRCA1/2 PVs while 2.3% had PVs in a syndromic gene (APC, MLH1, MSH2, MSH6, NF1, PMS2, and TP53) or an emerging breast/ovarian cancer gene (ATM, BARD1, BRIP1, CHEK2, NBN, PALB2, RAD51C and RAD51D). PVs in other tested genes were rare (generally <1%). VUS rates increased from patients diagnosed in 2013 (11.2% breast, 11.2% ovarian) to 2017 (26.4% breast, 26.8% ovarian) and were higher in racial/ethnic minorities (47.8% Asian, 46.0% Black, 40% Hispanic versus 24.6% non-Hispanic Whites diagnosed with ovarian cancer in 2017; p<.001). Conclusions: A substantial gap persists in testing ovarian cancer patients (34.5% versus nearly 100% recommended) while testing more genes was associated with a substantial racial/ethnic gap in VUS. Most clinically relevant PVs occurred in the 17 genes (ovarian cancer patients) to 20 genes (breast cancer patients) reported above; testing only these genes may optimize the clinically salient PV-to-VUS ratio, particularly for racial/ethnic minorities. Citation Format: Allison W Kurian, Monica Morrow, Steven Katz. Trends in genetic testing and results for women diagnosed with breast cancer or ovarian cancer, 2013-2017 [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD10-01.