Post-transplant lymphomas: a 20-year epidemiologic, clinical and pathologic study in a single center

Abstract

Background and objectives: to study the incidence, clinical presentation, pathologic features and outcome of post-transplant lymphomas (PTL) during the past 20 years. Design and methods: we undertook a descriptive study of all biopsy-proven cases of PTL diagnosed in our hospital from 1979 through 1999. The average annual incidence rate of PTL was analyzed at 5-year intervals from 1979 to 1999. Risk ratios were estimated by comparing the incidence of PTL among transplanted patients with that of lymphoma observed in the general population of the region. Survival analysis was performed at the univariate level using the Kaplan Meier technique and at the multivariate level by Cox hazard models. Results: seventeen of 1,860 transplanted patients developed a PTL (0.9%). The risk of PTL was calculated to be almost 8-fold higher than the risk of lymphoma in the general population. The risk was highest among those who had received a heart transplant (RR=35.6). The mean time between transplant and the diagnosis of PTL was 31 +/- 29 months. Of all PTL, 88% were of B-cell origin and 53% of the cases tested were Epstein-Barr virus (EBV)-positive. The median survival was 24 months. The majority of patients with allograft involvement died within the 2 months following diagnosis (hazard ratio 5.3; 95% CI 1.4-20.7). Interpretation and conclusions: organ transplantation is a major risk factor for the development of lymphoma, a disease with a particularly bad prognosis when it develops at the site of the allograft. Early diagnosis and more specific treatment may improve PTL survival.