Abstract 1025: Risk of diffuse large B-cell lymphoma in solid organ transplant recipients

Abstract

Abstract Introduction: Solid organ transplants, while potentially life-saving treatments, are associated with increased risk of non-Hodgkin lymphomas (NHL) due to chronic immunosuppression, viral infection, and other factors. Given the etiologic heterogeneity of NHL subtypes, we conducted the first comprehensive evaluation among solid organ transplant recipients of factors that may specifically impact risk for diffuse large B-cell lymphoma (DLBCL), a common and highly aggressive NHL subtype that has been closely associated with immune perturbation. Materials and Methods: Data from the Scientific Registry of Transplant Recipients (SRTR) were linked to 14 population-based U.S. cancer registries by probabilistic matching and manual review to identify a cohort of 178,522 transplant recipients for follow-up and ascertainment of incident DLBCL. We calculated standardized incidence ratios (SIR = observed/expected cases) to compare the relative risk of DLBCL in transplant recipients with that expected in the general population. Differences between SIRs among patient groups were evaluated in multivariable Poisson regression models. Results: We identified 948 cases of DLBCL in the cohort, accounting for more than half of the 1,617 NHLs diagnosed, compared with 70.0 cases expected in the general population (SIR = 13.5, 95% CI = 12.7-14.4). Kidney was the most commonly transplanted organ in the cohort (59%, SIR = 11.0, 95% CI =10.0-12.1), but the SIR for DLBCL was highest after lung (SIR = 39.5, 95% CI = 31.7-48.7) and pancreas or kidney-pancreas transplants (SIR = 32.6, 95% CI = 24.6-42.5; Phomogeneity <0.01). The very high SIR in recipients aged 0-19 at transplantation (SIR = 378.9, 95% CI 318.3-447.6) dropped rapidly with advancing age (Ptrend<0.01) but was still markedly elevated among recipients aged ≥65 at transplantation (SIR = 5.8, 95% CI 4.6-7.3). Females had higher SIRs for DLBCL than males (15.8 vs. 12.6; Phomogeneity = 0.02). DLBCL risks were particularly striking for recipients who were Epstein-Barr virus (EBV) seronegative at time of transplant (SIR = 43.7, 95% CI = 34.7-54.3) compared with EBV seropositive recipients (SIR = 9.3, 95% CI = 7.6-11.1; Phomogeneity <0.01). This difference was even more pronounced for DLBCLs occurring within 2 years of transplantation (SIR = 78.8 vs. 11.8 in EBV seronegative vs. seropositive recipients). Conclusion: The risk of DLBCL, a common and aggressive subtype of NHL, was found to be greatly increased in solid organ transplant recipients compared with the general population. Particularly high SIRs were observed for the youngest recipients, as well as recipients who were EBV seronegative at time of transplant, highlighting the importance of primary EBV infection following transplant. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1025. doi:1538-7445.AM2012-1025