Post-transplant lymphoproliferative disorders: improved outcome after clinico-pathologically tailored treatment.

BACKGROUND AND OBJECTIVES: Clinical and pathologic variability of post-transplant lymphoproliferative disorders (PTLDs), their aggressive behavior and the recognized therapy-related toxicity make management of patients with these disorders difficult. Assessment of first-line treatment and identification of prognostic factors need to be better defined.

DESIGN AND METHODS: Data on 40 PTLDs which developed in adult solid organ recipients were analyzed in order to evaluate clinical and pathologic features, response to treatment and prognostic factors. Data were collected retrospectively between 1989 and 1996; since 1997 a prospective study has been activated.

RESULTS: The median time from transplant to PTLD was 56 months. Regarding histologic features, plasmacytic hyperplasia was diagnosed in 5 patients (12.5%), polymorphic lymphoproliferative disorders in 3 (7.5%), malignant lymphoma in 32 (80%). The diagnosis was made at autopsy in eight patients (20%). Late-onset PTLDs (>12 months from transplant) occurred in 33 patients (83%), EBV-negative forms in 12 (31%). Relevant differences have been observed between EBV-positive and EBV-negative forms. Twenty-nine patients completed their scheduled treatment and are evaluable for outcome. The cumulative probability of survival at 1 year is 57% (CI 37.6-73.4) and the median survival time of the entire group has not been reached at 54 months. Clinical stage, performance status, lactate dehydrogenase and number of sites are predictive factors for survival. The International Prognostic Index and the PTLD index are able to identify different risk groups.

INTERPRETATION AND CONCLUSIONS: Although rare, PTLDs are a significant cause of mortality in allograft recipients. Therapy tailored on histologic and clinical features of PTLD is feasible and is able to give long-lasting complete responses.