Liquid biopsy using cfDNA to predict radiation therapy response in solid tumors.

Area of Science:

• Oncology
• Genomics

Background:

• Radiation therapy (RT) is a cornerstone treatment for solid tumors.
• Monitoring treatment response and detecting minimal residual disease (MRD) are critical for patient outcomes.
• Cell-free DNA (cfDNA) analysis offers a non-invasive approach for molecular monitoring.

Purpose of the Study:

• To explore the feasibility of using cfDNA I-scores to monitor treatment response in patients undergoing RT for solid tumors.
• To assess the utility of cfDNA I-scores in detecting chromosomal instabilities as a marker of treatment efficacy.

Main Methods:

• Enrolled 23 patients with lung, esophageal, and head and neck cancers treated with RT.
• Collected serial cfDNA samples pre-RT, 1 week post-RT (P1W), and 1 month post-RT (P1M).
• Performed low-depth whole-genome sequencing and calculated I-scores to quantify genome-wide copy number instability.

Main Results:

• Elevated pretreatment I-scores (>5.09) were observed in 73.9% of patients.
• A significant positive correlation was found between gross tumor volume and baseline I-score (p=0.047).
• Median I-scores decreased significantly from baseline (5.27) to P1M (4.79) (p=0.002), but not to P1W (5.13).

Conclusions:

• Demonstrated the feasibility of cfDNA I-score for detecting minimal residual disease post-RT in lung, esophageal, and head and neck cancers.
• Suggests cfDNA I-score as a potential biomarker for monitoring RT response.
• Further studies are warranted to optimize I-score measurement for predicting radiation response.