Stage I Colon Cancer

This multicenter prospective observational cohort study will enroll 392 patients with stage I-III colon adenocarcinoma who undergo curative resection and whose tumors harbor at least one prespecified oncogenic driver mutation (KRAS, NRAS, BRAF, or PIK3CA). Serial plasma circulating tumor DNA (ctDNA) testing for molecular residual disease (MRD) will be performed with a standardized 10-gene next-generation sequencing (NGS) panel at predefined time points during 3 years of postoperative follow-up. The primary objective is to evaluate the association between postoperative ctDNA-based MRD status and recurrence-free survival (RFS). Secondary objectives include evaluating overall survival (OS), the interval between first MRD detection and radiologically confirmed recurrence, and the association between longitudinal MRD changes and outcomes following adjuvant chemotherapy.

This is a Phase II open-label trial of neoadjuvant immunochemotherapy with Atezolizumab and CAPOX followed by surgery and potentially adjuvant chemotherapy for patients with localized resectable pMMR adenocarcinoma of the colon with a target accrual of 28 patients. The investigators will explore if appropriately timed neoadjuvant CAPOX with anti-PD-L1 mAb (Atezolizumab) can be administered safely and feasibly, and that this combination will lead to improved clinical response associated with enhanced numbers of immune cells in surgically resected colon tumors. Patients will receive 4 cycles of atezolizumab in combination with 4 cycles of CAPOX (atezolizumab will be administered prior to chemotherapy) before standard of care surgical resection. Following surgery, patients still considered to be at high-risk of recurrence (per SOC guidelines) will receive further adjuvant chemotherapy (mFOLFOX6 or CAPOX), based on the discretion of the treating oncologist/investigator. Circulating tumor DNA (ctDNA) dynamic change status will be analyzed through collection of blood samples throughout different stages of the patient's neoadjuvant treatment regimen (baseline, pre-neoadjuvant therapy, mid-neoadjuvant, post-neoadjuvant therapy, and during postoperative period) as a marker of early read on efficacy. The end of the study for each patient enrolled will be at the 6 month postoperative visit. On Study Protocol: Patients will be followed up for an efficacy follow-up phase during the first 6 months after surgery (week 2 \& months 3, 6 visits). All assessments beyond the 6 month visit will be performed under standard of care surveillance office visits. Off Study Protocol: Thereafter they will enter a survival follow-up phase per standard of care protocols. Patients will be seen every 6 months starting at month 12 until month 36. All collection of research-specific assessments including whole blood, stool collection and quality of life questionnaires will be optional beyond the 6 month postop visit (months 12-36).