Detection of circulating tumor cell DNA for monitoring advanced gastric cancer

Introduction: Circulating tumor DNA (ctDNA) for monitoring the effects of chemotherapy and predicting prognosis in advanced gastric cancer have not been thoroughly investigated. Methods: We performed next-generation sequencing (NGS) of ctDNA from 23 gastric cancer patients. Then the genetic information and clinical information were statistically analyzed. Results: In this study, the frequency of TP53 was significantly different between the effective and ineffective groups (P = 0.040), and the number of TP53 mutations was more frequent in the ineffective group. Missense mutation was a significant difference between the treatment effect groups (P = 0.026). The number of gene mutations and the change in copy number levels were related to therapeutic effect. Among the ineffective group, there was a significant difference in the number of gene mutations (P = 0.0006). We further divided the number of gene mutations into an increase group and a decrease group, and found that there was a significant difference between the effective and ineffective groups (P = 0.038). Finally, it was found that patients with high mutation abundance of gastric cancer had a shorter overall survival than patients with low mutation abundance (P<0.05). Conclusion: ctDNA can be used as an effective tool to monitor the efficacy of chemotherapy and predict prognosis in advanced gastric cancer.