Abscopal Regressions of Lymphoma After Involved-Site Radiation Therapy Confirmed by Positron Emission Tomography

Abstract

Purpose: Patients with abscopal regressions of lymphoma after palliative involved-site radiation therapy (ISRT), detected on sequential 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), were identified by audit. A retrospective analysis was subsequently conducted to estimate the frequency of abscopal regression in follicular lymphoma (FL). Methods and Materials: Potential cases were identified at multidisciplinary lymphoma meetings and fulfilled these criteria: (1) palliative ISRT given for histologically confirmed lymphoma, (2) >2 lesions visualized on FDG-PET, (3) >1 unirradiated lesion(s) outside ISRT volume, (4) no systemic therapy delivered <2 months before radiation therap..