S3112 Revealing Prevalence and Mortality Risk of Gastrointestinal Malignancies After Solid Organ Transplantation: Insights From a National Data Registry

Introduction: Solid organ transplant recipients (SOTRs) are at increased risk for malignancies and gastrointestinal (GI) malignancy-related mortality in this population is not well characterized. We aimed to evaluate post-transplant GI malignancy-related mortality using a national electronic health record database. Methods: We performed a retrospective cohort study using the TriNetX Health Research Platform. Adult recipients of liver, kidney, heart, or lung transplants (2005-2025) without prior malignancy were included. GI cancers were identified using ICD codes. The primary outcome was mortality. Cox regression compared mortality by transplant type and GI malignancy. Results: Of 83,021 SOTRs, 2,445 developed GI malignancy. They were older (59.7 ± 12.6 vs 49.8 ± 16.7 years), more often male (66.6% vs 60.4%), and more frequently White (58.6% vs 49.6%) than those without malignancy (all P < 0.0001). Liver transplant recipients were disproportionately represented in the GI malignancy group (44.72% of cases; P < 0.0001). Nicotine dependence (13.9% vs 8.07%), and alcohol-related disorders (15.49% vs 7.86%) were more prevalent among those with GI malignancies (all P < 0.0001). Use of cyclosporine (12% vs 9%; P < 0.0001) and Sirolimus (15% vs 8%; P < 0.0001) was higher in the malignancy group. Mortality was 33% in the GI malignancy group vs 15% in the non-malignancy group (relative risk 2.20; P < 0.0001). Among SOTRs with GI malignancy, mortality was highest in renal transplant recipients, including esophageal (64%, hazard ratio [HR] 5.77), stomach (54.3%, HR 10.24), pancreatic (52%, HR 7.38), and colon cancers (39.5%, HR 3.79). Lung recipients also had worse outcomes, particularly with stomach (87%, HR 3.35), liver/bile duct (73.5%, HR 3.18), and colon cancers (57.4%, HR 2.66). In contrast, liver recipients had lower mortality, including for liver/bile duct cancers (21%, HR 1.14), possibly due to organ-specific surveillance or immunosuppressive regimens. Heart recipients had intermediate outcomes, with colon cancer mortality at 45.6% (HR 2.56). Conclusion: GI malignancies in SOTRs have markedly variable survival outcomes depending on cancer type and transplanted organ, with lung and renal recipients facing the highest mortality from stomach and colon cancers. Further research into transplant and malignancy-specific screening protocols and integrating these insights into post-transplant care pathways may enable earlier detection and improved survival in this high-risk population.