Therapeutic options

In some cases, withdrawal of immunosuppression results in eradication of the lymphoma.[76,77] When this is unsuccessful or not feasible, a course of rituximab may be considered because it has shown durable remissions in approximately 60% of patients and a favorable toxicity profile.[76,78,79] If these measures fail, doxorubicin-based combination chemotherapy (R-CHOP) is recommended, although some patients can avoid cytotoxic therapy.[79,80] Localized presentations can be controlled with surgery or radiation therapy alone. These localized mass lesions, which may grow over a period of months, are often phenotypically polyclonal and tend to occur within weeks or a few months after transplant.[73] Multifocal, rapidly progressive disease occurs late after transplant (>1 year) and is usually phenotypically monoclonal and associated with EBV.[81] These patients may have durable remissions using standard chemotherapy regimens for aggressive lymphoma.[81-83] Instances of EBV-negative PTLD occur even later (median, 5 years posttransplant) and have a worse prognosis; R-CHOP can be given directly in this circumstance.[84] A sustained clinical response in patients with chemotherapy-refractory disease was attained using an immunotoxin (anti-CD22 B-cell surface antigen antibody linked with ricin, a plant toxin).[85] An anti-interleukin-6 monoclonal antibody is also under clinical evaluation.[86]