Implementation of universal germline testing in underserved patients with young onset gastrointestinal cancer.

10602 Background: Universal germline testing (UGT) in solid cancer patients increases the detection of pathogenic germline variants (PGVs) over guideline-based testing. There is a rising incidence of young onset (YO) gastrointestinal (GI) cancers (50 years and under). PGV rates in this population can be as high as 20%, highlighting the benefit of UGT. Underserved populations experience significant disparities in germline testing. The primary aim of this study is to evaluate rates of germline testing among patients with young onset (YO) GI cancers in a large safety net population and identify barriers and facilitators of testing in order to improve the process. Methods: In this retrospective study, we identified 202 patients ages 18-50 diagnosed with GI cancers between January 2019 and December 2022 at the Lyndon B. Johnson Hospital. Demographic and clinical data were collected and the rate, outcome and process of standard of care germline testing evaluated. Paired T-tests were used to identify factors associated with timeliness and completion of germline. Results: The majority of patients had colorectal (68%) followed by gastro-esophageal cancers (16%). Median age at diagnosis was 42 years. One third were diagnosed with stage IV disease. Half of all patients were recipients of financial assistance based on household income less than 150% of the Federal Poverty Level. Spanish was the primary language spoken by 58% of patients. Among all patients, 148 (73%) were referred to a genetics counselor with germline testing offered in 111 (55%) and completed in 99 (49%). PGVs were identified in 17% of patients tested while variants of uncertain significance were found in 19%. Patients with colon cancer (p<0.001), microsatellite instability on immunohistochemistry (p<0.001), and those with a first-degree relative with cancer (p<0.001) were more likely to complete genetic testing. The average time from initial oncology visit to genetics referral was 20 weeks while that from referral to genetics appointment was 22.5 weeks. The average time from genetics appointment to completion of testing was 14.5 weeks. Patients with private insurance had a significantly shorter time to genetics referral (p<0.05) while English-speakers had a longer time from referral to initial genetics appointment (p 0.019) and to completion of testing (p 0.044). Uninsured patients had significantly lengthier times to test completion (p 0.013). Conclusions: PGVs were detected in 17% of patients with YO GI cancers. Along the genetics services care delivery continuum, patient selection for genetic counselor referral, uptake of genetic testing and timeliness of testing were identified as key barriers to germline testing. Given the high detection rate and barriers to testing identified in this underserved population, we have designed a multilevel intervention aimed at optimizing the implementation of UGT in patients with YO GI cancers.