Abstract 591P
Background
For endometrial cancer patients, liquid biopsy based on whole blood is less invasive than endometrial biopsy and has the potential to be serially collected for monitoring after hysterectomy. Thus, we analyzed serially obtained ctDNA from endometrial cancer patients undergoing staging operation.
Methods
Patients diagnosed with endometrial cancer since January 2021 were prospectively enrolled. Whole blood samples were collected prior to staging operation and every three months thereafter. Control samples were obtained from patients undergoing hysterectomy for benign indication. ctDNA was extracted and analyzed with a custom panel covering 100 endometrial cancer-related genes. Prepared libraries were sequenced using NovaSeq 6000 System (Illumina) and analyzed using PiSeq analysis (Dxome).
Results
A total of 91 patients, including 72 endometrial cancer and 19 control patients, contributed 154 samples for analysis. Endometrial cancer patients consisted of 43 patients with uterine confined disease (stage IA, 32%; IB, 17%; II, 5%) and 23 patients with advanced disease (stage III, 18%; IV or recurrent, 28%). The detection rate was higher in advanced (65%) compared to uterine confined disease (29%) (p-value=0.01). Stratified by clinical stage, sensitivity and specificity with respect to cancer detection were 61% and 94.6% for advanced disease and 23% and 94.7% for uterine confined disease, respectively. Genomic landscape analysis of 30 patients harboring pathogenic mutations at baseline highlighted frequently altered genes such as TP53 (43%), PTEN (37%), ARID1A (23%), PIK3CA (13%). Other interesting genes included MSH6 (7%), and CTNNB1 (3%). Analysis of 35 patients with serial samples showed that among 13 patients with detectable somatic mutation at baseline, negative conversion was found in 8 patients and persistent mutation in 5 patients.
Conclusions
Detection and monitoring by whole blood-based ctDNA is feasible in endometrial cancer patients, especially those with advanced stage disease who may benefit from heightened surveillance after surgery. Genomic mutations as well as their trend may help tailor adjuvant therapy. Updated analysis with additional patients will be shared at the conference.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.