Disparities and barriers in germline testing among patients with early-onset gastrointestinal cancers.

35 Background: Early-onset gastrointestinal cancers (EOGIC) are strongly associated with hereditary predisposition, making germline testing essential for treatment and familial risk management. Disparities in germline testing persist. This study investigates disparities and barriers to germline testing in EOGIC. Methods: This IRB-approved retrospective analysis included 864 patients aged 18-49 with GI cancers at the University of Chicago (2018-2023). Data collected included race, gender, age, insurance, family cancer history, and subtype. Outcomes were physician referrals for germline testing and completion. Chi-square tests and logistic regression models assessed predictors of recommendations and completion. Results: Of 864 patients, 473 (54.7%) received germline testing recommendations, and 323 (37.4%) completed testing. Completion rates: 30.2% for no insurance, 29.1% for Medicare/Medicaid, and 40.3% for private insurance (p=0.032). Patients with family history of cancer were more likely to be recommended for testing (62.9% vs. 39.5%, p<0.001) and complete it (44.0% vs. 23.7%, p<0.001). In our cohort, no significant racial disparities were observed (p=0.712 and p=0.358). Females were more likely to receive recommendations (59.1%) and complete testing (41.2%) than males (50.9% referral, 34.0% completion, p=0.016 and p=0.029). Patients under 30 had the highest rates of testing recommendation (66.1%) and completion (46.4%), followed by 30-39 (61.7%, 44.4%) and 40-49 (51.2%, 34.0%), p=0.006 and p=0.009. By cancer subtype, colorectal cancer (CRC) patients had the highest referral (66.1%) and completion (45.9%) rates, while anal cancer had the lowest (13.2% referral, 5.3% completion, OR 0.08, p<0.0001). Gastric cancer (52.3% referral, 29.2% completion, OR 0.49, p=0.005) and esophageal cancer (36.9% referral, 20.0% completion, OR 0.31, p<0.0001) also had lower testing rates. Liver cancer (35.4% referral, 27.1% completion, OR 0.38, p<0.0001) and cholangiocarcinoma (45.5% referral, 22.7% completion, OR 0.28, p=0.016) showed similarly low rates. Conclusions: Disparities in germline testing were seen among uninsured patients, males, and those with public insurance. CRC had the highest testing rates, while anal, esophageal, liver, and cholangiocarcinoma had lower rates, likely due to lower suspicion of hereditary predisposition. Targeted interventions are needed to improve testing uptake and completion, especially among uninsured and underrepresented populations.