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
Authors: Alvarado Monica , Hoffman Trevor , Haque Reina , Kershberg Hilary , Goff John 
Published: September 2024

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.