This study aims to evaluate the clinical performance of blood-based Minimal Residual Disease (MRD) testing using circulating tumor DNA (ctDNA) in patients with endometrial and cervical cancer. The researchers will investigate whether MRD detection can identify cancer recurrence earlier than current standard imaging or clinical methods (providing a "lead time"). Participants will undergo blood collection at specific time points, including at diagnosis, after surgery, and during regular follow-up visits. The study will also assess the correlation between MRD status and survival outcomes, such as Relapse-Free Survival (RFS) and Overall Survival (OS). The goal is to establish a foundation for personalized treatment strategies based on molecular monitoring.

Despite standard treatments, a significant number of patients with endometrial and cervical cancer experience recurrence. Current monitoring relies on imaging (CT/MRI) and tumor markers (CA-125, SCC-Ag), which often detect recurrence only after a visible tumor mass has formed. This prospective cohort study evaluates the utility of ctDNA-based MRD testing as a high-sensitivity biomarker for early detection.

Study Population and Workflow: A total of 600 participants (300 with endometrial cancer and 300 with cervical cancer) will be enrolled. The study involves the following procedures:

Tumor Tissue Collection: Formalin-fixed paraffin-embedded (FFPE) tissue from surgery or biopsy will be collected for genomic profiling.

Serial Blood Collection: Peripheral blood samples (approximately 20ml) will be collected at:

Baseline (before surgery or CCRT)

Post-operative (within 4 weeks after surgery)

Post-adjuvant therapy (within 4 weeks after completion of chemotherapy or CCRT)

Surveillance (every 3 months for the first 2 years, then every 6 months)

MRD Analysis: Deep sequencing of plasma cell-free DNA (cfDNA) will be performed to track tumor-specific variants.

Objectives: The primary objective is to calculate the "lead time," defined as the interval between the first MRD-positive result and clinical/radiological recurrence. Secondary objectives include evaluating the sensitivity and specificity of the MRD assay and its association with RFS and OS. By comparing MRD dynamics with conventional biomarkers, this study seeks to determine if molecular monitoring can provide a more accurate assessment of a patient's prognosis and risk of relapse.

Inclusion Criteria:

• Histologically confirmed endometrial cancer or cervical cancer.
• Scheduled for or completed standard treatment (Surgery, Adjuvant therapy, or CCRT).
• Provision of written informed consent for study participation and biospecimen collection

Exclusion Criteria:

• Synchronous other malignancies (cancer requiring treatment within the last 5 years).
• Persistent infection or bleeding tendency that makes repeated blood collection unsafe.
• Inability to follow-up or communicate (e.g., due to geographic or cognitive reasons).
• Any condition that the principal investigator deems inappropriate for the study.

The study population consists of female patients aged 19 to 79 who have been histologically diagnosed with either endometrial cancer or cervical cancer at Asan Medical Center. This cohort includes patients across various stages of the disease who are scheduled to undergo or have completed standard-of-care treatments, such as radical surgery, adjuvant chemotherapy, radiotherapy, or concurrent chemoradiotherapy (CCRT). The population is designed to represent a real-world clinical setting of gynecologic oncology patients to evaluate the effectiveness of MRD monitoring in predicting recurrence and survival outcomes.