CORRELATION BETWEEN SERUM CIRCULATING TUMOR DNA LEVELS AND LYMPH NODE RATIO IN PATIENTS WITH COLORECTAL CANCER

Introduction Colorectal cancer (CRC) is the most prevalent malignancy worldwide. Colonoscopy is the gold standard for CRC screening and diagnosis, but it is costly and requires preparation and sedation. Therefore, the identification of biomarkers to aid in CRC diagnosis is a pressing need in clinical practice. Among these, circulating free DNA (cfDNA) stands out. The detection of cfDNA involves a blood sample, which potentially increases patient adherence. Beyond its diagnostic role, this tool can be used in staging, assessing treatment response, and early detection of recurrences.

Objective To evaluate the relationship between serum cfDNA levels and the lymph node ratio in patients with CRC.

Methods A longitudinal and prospective study with molecular analysis of cfDNA liquid biopsy from 25 patients with CRC. Clinical and epidemiological data were collected from medical records. Continuous data with normal distribution were presented as mean ± standard deviation and compared using covariance analysis adjusted for age and gender. Data with non-parametric distribution were presented as median and interquartile range. Categorical variables were compared using the chi-square test.

Results The sample included 25 patients, of which 9 were male and 14 were female. Male sex (Odds Ratio - OR 0.045) and diabetes (OR 0.0000155) tended to be protective factors. However, hypertension was associated with more advanced staging. A higher lymph node ratio predominated in the third tertile of cfDNA levels. The estimated coefficient was 94.423 with a p-value of 0.000712, indicating a positive, linear, and statistically significant relationship between the lymph node ratio and cfDNA levels. In the adjusted chi-square analysis, approximately 43.28% of the variance in cfDNA levels was explained by the lymph node ratio. In the normal model, there was a trend suggesting that Body Mass Index (BMI) influenced staging, and when cfDNA levels were added to the analysis, the impact of BMI was reinforced.

Conclusion In this study, cfDNA was not shown to be a predictive factor for invasion depth or staging in CRC patients, but there was a strong relationship between this serum marker and lymph node involvement. Furthermore, BMI was the variable that demonstrated a statistically significant association with cfDNA levels.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025