Research on Colorectal Cancer Recurrence Monitoring and Individualized Treatment Based on MRD

Summary

This study aims to evaluate whether plasma molecular residual disease (MRD), assessed using circulating tumor DNA (ctDNA), can help optimize the duration of immunotherapy in patients with metastatic microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) colorectal cancer.

Patients with MSI-H/dMMR metastatic colorectal cancer can achieve durable responses to immune checkpoint inhibitors, but the optimal duration of treatment remains uncertain. Prolonged immunotherapy may increase treatment burden and the risk of immune-related adverse events. ctDNA-based MRD testing may provide a sensitive method for detecting residual tumor burden and identifying patients who may be able to safely stop treatment.

In this study, patients receiving immunotherapy will undergo serial plasma MRD testing. After completing 1 year of immunotherapy, patients with two consecutive negative MRD results will be randomly assigned to either continue immunotherapy or stop treatment and enter observation. Patients will then be followed every 3 months for 2 years with MRD testing and routine clinical assessments, including imaging and laboratory examinations.

The study will compare clinical outcomes between the two groups and evaluate whether serial plasma MRD monitoring can support a more individualized approach to the duration of immunotherapy in MSI-H/dMMR metastatic colorectal cancer.

Conditions

• Colorectal Cancer (MSI-H)
• Molecular Residual Disease

Interventions

OTHER

Discontinue NA Treatment

Patients with dMMR/MSI-H metastatic colorectal cancer who achieve an objective response after 1 year of immunotherapy and have two consecutive negative plasma MRD results will be randomized to discontinue immunotherapy. Patients will enter observation and undergo routine clinical and imaging assessments, with plasma MRD testing every 3 months until the study endpoint.

OTHER

Continued Immunotherapy

Patients with dMMR/MSI-H metastatic colorectal cancer who achieve an objective response after 1 year of immunotherapy and have two consecutive negative plasma MRD results will be randomized to continue immunotherapy for a total treatment duration of 2 years. Patients will undergo routine clinical and imaging assessments, with plasma MRD testing every 3 months until the study endpoint.

OTHER

Observation

Patients who achieve disease control for at least 6 months after immunotherapy will undergo plasma MRD testing and prospective follow-up. The study will not interfere with subsequent treatment decisions, including discontinuation or continuation of immunotherapy, surgery, or local treatment. Patients will undergo routine clinical follow-up and serial MRD monitoring according to the study schedule.

Sponsors & Collaborators

• Sun Yat-sen University

  lead OTHER

Principal Investigators

• Peirong Ding, M.D. · Sun Yat-Sen University Cancer Center

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-06-23

Primary Completion

2029-12-30

Completion

2034-12-30

Countries

• China

Study Locations