Introduction: Histologic transformation (HT) of indolent non-Hodgkin lymphomas is an event that results in considerable morbidity and mortality. The introduction of chemoimmunotherapy regimens has resulted in an improvement in the management of this disease, and consolidation of responses with autologous stem cell transplantation appears efficacious. Many patients are not eligible for high-dose therapy, however. Radioimmunotherapy (RIT) has demonstrated single-agent efficacy in HT and can be used safely as consolidation after chemoimmunotherapy. For these reasons, RIT consolidation after chemoimmunotherapy induction has been our standard treatment approach at the University of Rochester for patients with HT who were ineligible for autologous stem cell transplantation.
Patients and methods: A retrospective cohort study was performed to describe the clinical outcomes of these patients. Twenty-one patients were identified who received RIT consolidation. The Kaplan-Meier method was used to estimate the distributions of overall survival and progression-free survival. Comparisons were made between patients with pathologic HT and the combination of clinical HT and composite lymphoma using the log-rank test to compare survival curves.
Results: The median overall survival of the cohort was 84 months, and progression-free survival was 38 months. The major toxicity was myelosuppression, and 2 deaths were attributed to therapy. One case of therapy-related acute myeloid leukemia was noted.
Conclusion: In a population of patients ineligible for high-dose therapy with autologous stem cell support, consolidation of response to chemoimmunotherapy with RIT was well tolerated and should be considered in patients with disease responsive to induction therapy.
Keywords: (131)I-tositumomab; (90)Y-ibritumomab tiuxetan; indolent lymphoma; radioimmunoconjugate; transformed lymphoma.
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