ctDNA and Organ Preservation/Pathologic CR in Rectal Cancer

Inclusion Criteria

• •Participants with T3, T4, or node-positive non-metastatic rectal cancer.
• •Participants must have original tumor tissue (formalin-fixed, paraffin embedded specimens) available for analysis or be willing to undergo a baseline research biopsy.
• •Participants must be 18 years of age or older.
• •ECOG 0-2.
• •Participants must be eligible for at least 3 months of FOLFOX, FOLFIRINOX/FOLFOXIRI, or CAPOX
• •Participants must be eligible for long course chemoradiation to 40-54 Gy.
• •Participants must be able to understand and willing to sign a written informed consent document.