Circulating Tumor DNA (ctDNA) Clearance May Predict Treatment Response in Neoadjuvant Colorectal Cancer Management

Area of Science:

• Oncology
• Molecular Diagnostics
• Cancer Biomarkers

Background:

• Circulating tumor DNA (ctDNA) is extracellular DNA from tumors.
• ctDNA is a proposed marker for residual disease and recurrence predictor in adjuvant therapy.
• Limited data exist on ctDNA utility in the neoadjuvant setting.

Purpose of the Study:

• To evaluate the utility of ctDNA in the neoadjuvant setting for colorectal cancer.
• To assess the association between ctDNA conversion and treatment response.
• To explore the impact of ctDNA dynamics on treatment duration decisions.

Main Methods:

• Retrospective study of Stage III and IV colorectal cancer patients.
• Patients received neoadjuvant treatment at a single institution.
• Analysis of ctDNA status (positive/negative) before and during neoadjuvant therapy.

Main Results:

• 17 patients converted from positive to negative ctDNA pre-surgery.
• 5 patients remained persistently ctDNA positive despite treatment.
• ctDNA conversion associated with favorable treatment effect scores; no difference in recurrence-free survival.
• No added benefit from extended neoadjuvant therapy post-ctDNA conversion.

Conclusions:

• ctDNA shows potential utility in monitoring neoadjuvant treatment response.
• Prospective trials are needed to validate ctDNA's role in guiding treatment duration.
• Further research can optimize the use of ctDNA in neoadjuvant cancer care.