Priming Radioimmunotherapy With External Beam Radiation in Patients With Relapsed Low-Grade Non-Hodgkin Lymphoma

Abstract

Background: The aim of this study was to evaluate the outcomes of priming salvage radioimmunotherapy (RIT) with a low dose of external beam radiotherapy (EBRT) in patients with relapsed low grade non-Hodgkin lymphoma (LG-NHL). Methods: Patients who received salvage RIT with or without 2 × 2 Gy EBRT between March 2009 and February 2013 were retrospectively reviewed at a single institution. Planning target volume (PTV) for EBRT was created by adding a 1-2 cm expansion to the gross tumor volume depending on the anatomical location. Kaplan−Meier method via log-rank was employed to analyze the endpoints freedom from progression (FFP) and overall survival (OS). Results: We identified 22 patients who received salvage RIT without chemotherapy with a median follow up of 34 months. Of these, 9 (41%) patients were treated with EBRT immediately prior to RIT, and 13 (59%) received salvage RIT alone. Median FFP was not reached in patients who underwent combination treatment, while it was 9 months for patients treated with RIT alone (p = 0.02). OS for all patients at 36 months was 80.3% with no significant difference between the two groups (p = 0.88). On univariate analysis, the addition of EBRT was associated with improved FFP [hazard ratio (HR) = 4.17; 95% confidence interval (CI), 1.24-19.1; p = 0.02)]. No long term toxicities were reported in both groups. Conclusions: RIT outcomes and effects were improved with addition of low-dose EBRT immediately prior to it, in the treatment of relapsed LG-NHL with no additional toxicity. This study is hypothesis-generating and the findings should be validated in prospective studies.

Combination of 177Lu‐lilotomab with rituximab significantly improves the therapeutic outcome in preclinical models of non‐Hodgkin's lymphoma

“…Treatment with high‐dose External Beam Radiation (EBR) upregulates antigens such as HER2, EGFR and CD20 in cancer cells, and an increase in the antigen expression is correlated with an increase in anti‐tumour activity of immunotherapies targeting these antigens . Patients treated with low‐dose EBR immediately prior to anti‐CD20 radioimmunotherapy (RIT) with ibritumomab tiuxetan conjugated to Yttrium‐90 had longer freedom from progression (FFP) than patients only treated with RIT with no additional toxicity . The authors hypothesised that the superior therapeutic effect of anti‐CD20 RIT after EBR was due to surface upregulation of CD20 after EBR.…”

“…15,18,19 Patients treated with low-dose EBR immediately prior to anti-CD20 radioimmunotherapy (RIT) with ibritumomab tiuxetan conjugated to Yttrium-90 had longer freedom from progression (FFP) than patients only treated with RIT with no additional toxicity. 20 The authors hypothesised that the superior therapeutic effect of anti-CD20 RIT after EBR was due to surface upregulation of CD20 after EBR. We wanted to study if the selectively delivered low-dose rate radiation from 177 Lu-lilotomab affected the CD20 expression of NHL cells and subsequently altered the efficacy of rituximab.…”