Colorectal cancer in heart transplant recipients: A competing risk analysis

Background: Data on colorectal cancer (CRC) risk in heart transplant (HT) patients are limited, and screening recommendations specific to this population, especially patients under age 45, are lacking. We aimed to assess the incidence of post-HT CRC, with a focus on the effect of age. Methods: Using data from the TriNetX Research Network, we identified 4516 adults (≥18 years) who received HT between 1996 and 2024 in the United States, based on CPT codes for HT (33945) and combined lung-HT (33935). CRC was identified from ICD-10 CM codes (C18, C19, & C20). Because mortality was higher than CRC risk, we used a competing risks framework to estimate CRC incidence. Results: After a median follow-up of 3.6 years (25th–75th percentile, 1.4–6.7), 48 patients developed CRC. Median time from HT to CRC was 4.5 years (.7–8.0). The cumulative incidence of CRC was 1.73% (CI: 1.22%–2.45%) at 10 years, corresponding to 173/100,000 person-years. In comparison, the United States age-adjusted general population rate was 36.5/100,000 between 2016 and 2020. Age at HT was not significantly associated with CRC risk (p =.22); patients age < 45 at HT experienced similar risk as patients ≥45. The CRC risk difference between men and women was not significant (1.89% vs. 1.23% at 10 years; p =.74). All-cause mortality was 20.4% at 5 years and 38.8% at 10 years. Conclusions: In this HT cohort, CRC risk was markedly higher compared to the general population and did not differ by age, suggesting that HT recipients may require screening for CRC regardless of age.