Utility of circulating tumor DNA for detection and monitoring of endometrial cancer recurrence and progression

Abstract

ABSTRACTDespite the increasing incidence of endometrial cancer (EC) worldwide and the poor overall survival of patients who recur, no reliable biomarker exists for detecting and monitoring EC recurrence and progression during routine follow-up. Circulating tumor DNA (ctDNA) is a sensitive method for monitoring cancer activity and stratifying patients that are likely to respond to therapy. As a pilot study, we investigated the utility of ctDNA for detecting and monitoring EC recurrence and progression in 13 patients using targeted next-generation sequencing (tNGS) and personalized ctDNA assays. Using tNGS, at least 1 somatic mutation at a variant allele frequency (VAF) >20% was detected in 69% (9/13) of patient tumors. The four patients with no detectable tumor mutations at >20% VAF were whole exome sequenced, with all four harboring mutations in genes not analyzed by tNGS. Analysis of matched and longitudinal plasma DNA revealed earlier detection of EC recurrence and progression and dynamic kinetics of ctDNA levels reflecting treatment response. We also detected acquired high microsatellite instability (MSI-H) in ctDNA from one patient whose primary tumor was MSI stable. Our study suggests that ctDNA analysis, and in particular MSI analysis in ctDNA could become a useful biomarker for early detection and monitoring of EC recurrence and progression.