Analysis of ctDNA
tumor, stage II disease
DISEASE, TUMOR
The collected plasma samples at the pre-treatment period were analyzed in 38 patients. ctDNA was detected in 89.5% (34/38) of pre-treatment samples overall, including 21.1% (8/38) with stage II disease and 68.4% (26/38) with stage III disease (Fig. Associations between circulating tumor DNA (ctDNA) and responses to neoadjuvant treatment. The ctDNA detection rate decreased during neoadjuvant treatment, from 89.5% before treatment (T0) to 34.2% after neoadjuvant treatment (T2), then continued to decrease to 27.6% after surgery (T3). Specifically, neoadjuvant N and N/C reduced ctDNA positivity by 42.9% (T3) and 18.2% (T3), respectively (Fig. We next evaluated whether ctDNA clearance was associated with pCR rates. Among the patients with detectable ctDNA at T0 and underwent the corresponding T2 plasma measurements, 23 were ctDNA-negative at T2, with a ctDNA clearance rate of 67.6% (23/34) in the whole cohort. The percentage of patients with ctDNA clearance who received neoadjuvant N/C was significantly higher than those who received N (75.8% vs. 20%; odds ratio = 11.49, 95%CI 0.94–64.36, Circulating tumor DNA (ctDNA) and survival outcomes. 