Abstract B100: Improving access to hereditary cancer genetic testing in diverse populations: Outcomes in over 33,000 patients tested by genetics and non-genetics providers in Kaiser Permanente Southern California

Abstract Kaiser Permanente Southern California is an integrated health care organization serving over 4.7 million members in 14 medical centers. KPSC members are 42% Hispanic/Latino, 28 % Non-Hispanic White, 11% Asian/Pacific Islander, 8% Black/African American, and 12% Other/Unk. To facilitate detection of hereditary cancer syndromes among patients with personal and/or family histories of breast, colorectal, ovarian, pancreas and other cancers, we offered a 48-gene hereditary cancer multigene-panel test designed to detect all the most common hereditary cancer conditions. Patients seen by genetic counselors or geneticists (Gen providers) receive pre-test genetic counseling and include those with a family history of cancer with or without personal history of cancer. Our mainstreaming program allows non-genetics (non-Gen) providers including medical and surgical oncologists, gastroenterologists, and other specialists to order the test at the point of care (based on NCCN criteria) on their patients with cancer without pre-test genetic counseling. Providers place the order in the EMR system and patients receive an email/text message with information about the test, potential results, links to educational videos and a Genetics phone number for questions. When results are ready patients receive an automatic email/text notifying them and providing a link to their test report. Those with a positive test result receive post-test genetic counseling. Patients with negative or uncertain significance (VUS) results receive a message with a link to their test report, information about their result and the option to schedule a visit with genetics. From April 2021 to May 2024, we completed 33,173 tests: 13,076 (39%) ordered by non-Gen and 20,097 (61%) by Gen providers. The results distribution was similar in both groups: pathogenic/likely pathogenic (PV/LPV): 15% for Gen orders, 12% for non-Gen; VUS: 28% Gen, 30% non-Gen, and negative: 56% Gen, 58% Non-Gen. The patients tested closely reflected the diversity of our population, except for under-representation of Hisp/Latino patients and over-representation of Non-Hisp Whites: 14,400 (42%); Hisp/Latino 9,863 (29%); Asian/PI 4,279 (13%); AA/Black 3,209 (9%); and Oth/Unk 2,415 (7%). Eliminating single MUTYH variants the top 5 genes with the highest number and percentage of PV/LPV results for each of the race/ethnicity categories were as follows: AA/Black: BRCA2=60, BRCA1=38, ATM=36, MUTYH=18; Asian/PI: BRCA2=101, ATM=40, BRCA1=37, PMS2=24; Hisp/Latino: BRCA2=250, BRCA1=171, ATM=127, CHEK2=125; CDKN2A=113; Non Hisp White: CHEK2=346; BRCA2=304; ATM=200, BRCA1=196, FH=100; Oth/Unk: BRCA2=50, BRCA1=41, CHEK2=40, PALB2=30, ATM=20. Our results represent one of the largest and most diverse patient cohorts completing hereditary cancer testing from a single institution. They indicate that mainstreaming hereditary cancer testing can improve access for patients from under-represented groups and suggest differences in the frequency of deleterious variants in different hereditary cancer genes across race/ethnic groups. Citation Format: Monica Alvarado, Trevor Hoffman, Reina Haque, Hilary Kershberg, John Goff. Improving access to hereditary cancer genetic testing in diverse populations: Outcomes in over 33,000 patients tested by genetics and non-genetics providers in Kaiser Permanente Southern California [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B100.