Posttransplant Lymphoproliferative Disorder in Adults Receiving Kidney Transplantation in British Columbia: A Retrospective Cohort Analysis

BACKGROUND: Posttransplant lymphoproliferative disorder (PTLD) is a major complication following kidney transplantation. OBJECTIVE: We undertook this study to characterize PTLD in kidney transplant patients in British Columbia with regard to incidence, patient and graft survival, histological subtypes, treatment modalities, and management of immunosuppression. DESIGN: Retrospective cohort analysis. SETTING: British Columbia. PATIENTS: All adult patients who underwent kidney transplantation in British Columbia between January 1, 1996, and December 31, 2012, were included. Patients less than 18 years of age at the time of first transplant and multiple organ transplant recipients were excluded from analysis. MEASUREMENTS: Patients with lymphoproliferative disorders that occurred subsequent to kidney transplantation were considered to have developed PTLD. METHODS: Cases of PTLD were identified by cross-referencing data abstracted from the provincial transplant agency’s clinical database with the provincial cancer agency’s lymphoma registry. Patients were followed up for the development of PTLD until December 31, 2012, and for outcomes of death and graft failure until December 31, 2014. Data collection was completed via an electronic chart review. RESULTS: Of 2217 kidney transplant recipients, 37 (1.7%) developed PTLD. Nine cases were early-onset PTLD, occurring within 1 year of transplant; of these cases, 6 were known/presumed Epstein-Barr virus mismatch, compared with only 2 of 28 late-onset cases. Patient survival for early-onset PTLD was 100% at 2 years post diagnosis. Late-onset PTLD had survival rates of 71.4% and 67.9% at 1 and 2 years, respectively. PTLD was associated with significantly decreased patient survival (P = .031) and graft survival (uncensored for death, P = .017), with median graft survival of PTLD and non-PTLD patients being 9.5 and 16 years, respectively. Immunosuppressant therapy was reduced in the majority of patients; additional therapies included rituximab monotherapy, CHOP-R, radiation, and surgery. LIMITATIONS: Limitations to this study include its retrospective nature and the unknown adherence of patients to prescribed immunosuppressant regimens. In addition, cumulative doses of immunosuppression received and the degree of immunosuppression reduction for PTLD management were not effectively captured. CONCLUSIONS: The incidence of PTLD in British Columbia following kidney transplantation was low and consistent with rates reported in the literature. The incidence of late-onset PTLD and its association with reduced patient and graft survival warrant further analysis of patients’ long-term immunosuppression.