Circulating tumor DNA in endometrial cancer: clinical significance and implications.

Circulating tumor DNA (ctDNA) is a promising non-invasive tool that has been demonstrated to be a clinically useful biomarker in several tumor types for risk stratification, prognosis, and early detection of recurrence. However, there are limited data on the clinical utility of ctDNA in endometrial cancer (EC) compared with other solid tumors. The evolution of EC management through the integration of molecular characterization into the treatment algorithm has intensified the need to develop more effective predictive biomarkers to optimize treatment and reduce clinical toxicities. Given its non-invasive nature and its ability to represent and complement tumor multiclonal spatial and temporal heterogeneity, ctDNA could act as a valid surrogate for tissue sampling. In addition to plasma ctDNA detection being associated with clinicopathologic features of tumor aggressiveness at pre-operative assessment, an association with reduced disease-free survival and overall survival has been observed in patients with detectable ctDNA. Moreover, the half-life of ctDNA is significantly shorter than CA125, and plasma levels are reported to be completely cleared from the blood within 1 week from surgical debulking. Therefore, ctDNA may serve as a dynamic biomarker for occult microscopic residual disease when assessed within the first 4 to 8 weeks after eradicative surgery. Few studies have reported high sensitivity of ctDNA in detecting disease recurrence at longitudinal follow-up, although there are limited data comparing ctDNA and traditional serum biomarkers (CA125 and HE4) in identifying recurrence. In the perspective of personalized oncology, ctDNA may potentially help improve adjuvant therapeutic management by escalating/de-escalating treatment based on ctDNA detection after surgery, during maintenance, or in the recurrent/metastatic setting, in addition to acting as a sensitive biomarker for early detection of recurrence. Several challenges hinder the use of ctDNA in EC, including the lack of standardized protocols, the low mutational burden, tumor heterogeneity, and background normal DNA, which limit assay sensitivity and specificity. In addition, the high cost of ctDNA analysis, particularly, next-generation sequencing, restricts its accessibility. Future trials should focus on cost-effective approaches to ensure sustainability and efficient resource allocation.