Evaluating the impact of Medicaid expansion on outcomes for patients with gastric cancer in Louisiana.

11069 Background: Prior to June 2016, Louisiana's Medicaid program did not extend coverage to adults, regardless of income. With the expansion, up to 138% of the Federal Poverty Level (FPL) became eligible for enrollment, allowing 784,310 adults to enroll in the state's Medicaid program as of June 2023. Medicaid expansion (ME) effects on gastric cancer treatments and outcomes have not been fully understood. This study seeks to investigate the impact of Medicaid expansion (ME) on gastric cancer outcomes, such as changes in presentation, treatment patterns, time-to-treatment, and survival in Louisiana patients. Methods: Patients with primary invasive gastric cancer were identified using the Louisiana Tumor Registry. Patients diagnosed with gastric cancer were stratified into pre-expansion (2012–2015) and post-expansion (2017–2020) periods. Patients under 18 years old, unknown gastrectomy status, and those with unknown insurance or socioeconomic data were excluded from the study. Results: A total of 2,554 patients diagnosed with primary invasive gastric cancer were analyzed, predominantly male (63.7%) and urban residents (85.3%). Post-ME, the uninsured rate decreased significantly from 5.5% to 2.2% (p<0.001), with the largest reductions observed in younger adults (12.4% to 4.1%; p<0.001), Black patients (7.2% to 1.7%; p<0.001), rural residents (5.7% to 2.3%; p<0.001), and individuals from high-poverty neighborhoods (3rd quartile: 5.6% to 2.6%; p=0.028; 4th quartile: 6.1% to 2.6%; p=0.004). For treatment patterns, chemotherapy use increased for local/regional disease (50.4% post-expansion vs. 47.6% pre-expansion; p=0.038), while gastrectomy rates remained stable (60.3% vs. 56.4%; p=0.119). The median time to treatment increased significantly for local/regional disease (38 days post-expansion vs. 29 days pre-expansion; p=0.031) and metastatic disease (33 days post-expansion vs. 30 days pre-expansion; p=0.184). Survival outcomes showed significant improvement for local/regional disease post-expansion, with 12-month survival increasing from 67.2% to 76.2% (p<0.001) and 24-month survival improving from 52.8% to 59.7% (p=0.008). For metastatic disease, 12-month survival improved modestly (30.5% vs. 25.9%; p=0.111), while 24-month survival remained unchanged (12.6% vs. 12.7%; p=0.968). Conclusions: Overall, Medicaid expansion reduced uninsured rates and improved access to chemotherapy and survival for local/regional gastric cancer. However, it had a limited impact on late-stage presentation and survival disparities across racial groups. Addressing systemic barriers and optimizing healthcare delivery remains critical to achieving equitable outcomes for gastric cancer patients.