Consolidative radioimmunotherapy after chemoimmunotherapy in patients with histologic transformation of indolent non Hodgkin lymphoma

Abstract Introduction Histologic transformation 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 transplant appears efficacious. Many patients are not eligible for high dose therapy however. Radioimmunotherapy has demonstrated single-agent efficacy in histologic transformation and can be used safely as consolidation after chemoimmunotherapy. For these reasons, radioimmunotherapy consolidation after chemoimmunotherapy induction has been our standard treatment approach at the University of Rochester for patients with histologic transformation who were ineligible for autologous stem cell transplant. Patients and Methods A retrospective cohort study was performed to describe the clinical outcomes of these patients. Twenty-one patients were identified who received radioimmunotherapy consolidation. The Kaplan-Meier method was used to estimate the distributions of OS and PFS. 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. Discussion In a population of patients ineligible for high dose therapy with autologous stem cell support, consolidation of response to chemoimmunotherapy with radioimmunotherapy was well tolerated and should be considered in patients responsive to induction therapy.