A Prospective Study of Clonal Evolution in Follicular Lymphoma: Circulating Tumor DNA Correlates with Overall Tumor Burden and Fluctuates over Time without Therapy

Background: Follicular lymphoma (FL) shows marked variation in clinical course including spontaneous regression and histologic transformation (HT). Watchful waiting (W&W) is routinely applied to pts with newly diagnosed FL, but monitoring strategies are not standardized. Pts with progression within 1-2y of diagnosis have worse outcomes, but the biologic basis is unclear and biologic-based classifiers are not routinely applied at diagnosis. Circulating tumor DNA (ctDNA) is a highly tumor-specific biomarker that is prognostic in aggressive B-cell lymphomas, but its ability to serially monitor FL remains undefined. We applied a next-generation sequencing assay to identify tumor clonotypes for serial monitoring of peripheral blood in pts with untreated FL as part of an ongoing prospective clinical trial [NCT03190928].