Using ctDNA Testing to Guide Organ-Preserving Treatment in Adults With Stage II-III Rectal Cancer

What this Trial Is About

Researchers are studying patients with stage II-III rectal adenocarcinoma to understand how circulating tumor DNA ctDNA levels in the blood relate to tumor response during and after treatment. The study aims to determine if the presence or absence of ctDNA measured by the Signatera test can indicate how rectal cancer responds to therapies, including total neoadjuvant therapy TNT. This research is observational and focuses on improving organ-preserving strategies in rectal cancer care. Participants will have blood samples collected before starting any neoadjuvant therapy, every two months during TNT, and then every three months for up to three years after completing TNT. Medical records will be reviewed, and tissue samples may be collected if archival tissue is not available. The study tracks several outcomes such as complete clinical response, ctDNA status, surgery rates, pathological response, watch-and-wait strategy use, disease-free survival, and overall survival. During the study, participants will undergo regular blood collection and medical record reviews to monitor ctDNA levels and clinical outcomes. The primary outcome is the rate of complete clinical response within three months after TNT. Secondary outcomes include ctDNA positivity, surgery rates, and survival measures followed for up to three years. This long-term observation will help characterize ctDNA patterns and their potential prognostic value in rectal cancer treatment.

Establishing a ctDNA Biomarker to Improve Organ Preserving Strategies in Patients With Rectal Cancer