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

PRIMARY OBJECTIVE:

I. To estimate the percentage of participants that achieve complete clinical response.

SECONDARY OBJECTIVES:

I. To assess circulating tumor deoxyribonucleic acid (ctDNA) status among participants receiving total neoadjuvant therapy (TNT).

II. To assess molecular residual disease (MRD i.e., ctDNA status). III. To assess the rate of transabdominal surgery. IV. To assess the rate pathological complete response after surgery. V. To assess the rate of watch and -wait (W\&W) after TNT. VI. To assess disease-free survival (DFS). VII. To assess overall survival (OS).

EXPLORATORY OBJECTIVES:

I. To characterize ctDNA clearance or non-clearance patterns during TNT. II. To correlate ctDNA levels with a participant's pathological features. III. To preliminary assess the prognostic performance of ctDNA levels in relation to participant's clinical outcome.

OUTLINE:

Patients undergo collection of blood samples at baseline (before any neoadjuvant therapy), every 2 months while undergoing TNT, and then every 3 months for up to 3 years after completion of TNT. Patients' medical records are also reviewed. Patients may undergo collection of tissue sample if an archival tissue sample is not available.

• Positive circulating tumor deoxyribonucleic acid (ctDNA) [Срок оценки: From date of baseline measure of ctDNA (i.e., number of mutant molecules per mL) to date of until the date of first documented progression, up to 3 years.]
• Positive ctDNA after completing TNT [Срок оценки: From date of baseline measure of ctDNA (i.e., number of mutant molecules per mL) to date of until the date of first documented progression, up to 3 years]
• Rate of transabdominal surgery [Срок оценки: Up to 3 years following completion of TNT]
• Rate of pathological complete response (pCR) [Срок оценки: From start of treatment until completion of surgery, up to 3 years.]
• Rate of watch and wait strategy [Срок оценки: Up to 3 years following completion of TNT]
• Disease-free survival [Срок оценки: Time between the date of surgery (or W&W population, the date of completing TNT) and the date of local or metastatic recurrence or death from any cause, assessed up to 3 years following completion of TNT]
• Overall survival [Срок оценки: Time between the date of signed consent to the date of death from any cause, assessed up to 3 years following completion of TNT]