Evaluation of the diagnostic and prognostic clinical values of circulating tumor DNA and cell-free DNA in pancreatic malignancies: a comprehensive meta-analysis.

Background: The diagnostic and prognostic clinical value of circulating tumor DNA (ctDNA) and cell-free DNA (cfDNA) in pancreatic malignancies are unclear. Herein, we aimed to perform a meta-analysis to evaluate ctDNA and cfDNA as potential diagnostic and prognostic biomarkers. Methods: PRISMA reporting guidelines were followed closely for conducting the current meta-analysis. The PubMed/Medline, Scopus, and Web of Science (WoS) databases were scanned in detail to identify eligible papers for the study. A quality assessment was performed in accordance with the REMARK criteria. The risk ratios (RRs) of the diagnostic accuracy of ctDNA compared to that of carbohydrate antigen 19.9 (CA 19.9) in all disease stages and the hazard ratios (HRs) of the prognostic role of ctDNA in overall survival (OS) were calculated with 95% confidence intervals (CIs). Results: A total of 18 papers were evaluated to assess the diagnostic accuracy and prognostic value of biomarkers related to pancreatic malignancies. The pooled analysis indicated that CA19.9 provides greater diagnostic accuracy across all disease stages than ctDNA or cfDNA (RR = 0.64, 95% CI: 0.50-0.82, p < 0.001). Additionally, in a secondary analysis focusing on prognosis, patients who were ctDNA-positive were found to have significantly worse OS (HR = 2.00, 95% CI: 1.51-2.66, p < 0.001). Conclusion: The findings of this meta-analysis demonstrated that CA19-9 still has greater diagnostic accuracy across all disease stages than KRAS mutations in ctDNA or cfDNA. Nonetheless, the presence of detectable levels of ctDNA was associated with worse patient outcomes regarding OS. There is a growing need for further research on this topic. Systematic review registration: https://doi.org/10.37766/inplasy2023.12.0092, identifier INPLASY2023120092.

A novel risk classification model integrating CEA, ctDNA, and pTN stage for stage 3 colon cancer: a post hoc analysis of the IDEA-France trial.

BACKGROUND: We assessed the added value of incorporating carcinoembryonic antigen (CEA) to circulating tumor DNA (ctDNA) and pathological TN (pTN) stage for risk classification in stage 3 colon cancer (CC). PATIENTS AND METHODS: We retrospectively analyzed postoperative CEA values in patients with CC from the IDEA-France phase 3 trial. The relation between disease-free survival (DFS) and CEA was modeled through restricted cubic splines. Prognostic value of CEA, ctDNA, and pTN was assessed with the Kaplan-Meier method. Multivariate analysis was used to identify prognostic and predictive factors for DFS. RESULTS: Among 696 patients (35%), CEA values were retrievable, and for 405 (20%) both CEA and ctDNA were available. An optimized CEA threshold of 2 ng/mL was identified, the 3-year DFS was 66.4% for patients above the threshold and 80.9% for those below (HR, 1.74; 95% CI, 1.33-2.28, P < .001). In multivariate analysis, CEA ≥ 2 ng/mL contributed significantly to model variability, becoming an independent prognostic factor for DFS (HR, 1.82; 95% CI,1.27-2.59), alongside ctDNA (HR, 1.88; 95% CI, 1.16-3.03) and pTN (HR, 1.78; 95% CI, 1.24-2.54). A novel integrated risk classification combining CEA, ctDNA, and pTN stage reclassified 19.8% of pT4/N2 patients as low risk and 2.5% of pT3/N1 patients as high risk. This new classification demonstrated the 3-year DFS of 80.8% for low-risk patients and 55.4% for high-risk patients (HR, 2.66, 95% CI, 1.84-3.86, P < .001). CONCLUSIONS: Postoperative CEA value is a prognostic factor for DFS in stage 3 CC, independently of ctDNA and pTN. It advocates for systematic reporting in future adjuvant trials. Integrating both biomarkers with pTN could refine risk classification in stage 3 CC.

Novel liquid biopsy CNV biomarkers in malignant melanoma.

Malignant melanoma (MM) is known for its abundance of genetic alterations and a tendency for rapid metastasizing. Identification of novel plasma biomarkers may enhance non-invasive diagnostics and disease monitoring. Initially, we examined copy number variations (CNV) in CDK genes (CDKN2A, CDKN2B, CDK4) using MLPA (gDNA) and ddPCR (ctDNA) analysis. Subsequently, low-coverage whole genome sequencing (lcWGS) was used to identify the most common CNV in plasma samples, followed by ddPCR verification of chosen biomarkers. CNV alterations in CDK genes were identified in 33.3% of FFPE samples (Clark IV, V only). Detection of the same genes in MM plasma showed no significance, neither compared to healthy plasmas nor between pre- versus post-surgery plasma. Sequencing data showed the most common CNV occurring in 6q27, 4p16.1, 10p15.3, 10q22.3, 13q34, 18q23, 20q11.21-q13.12 and 22q13.33. CNV in four chosen genes (KIF25, E2F1, DIP2C and TFG) were verified by ddPCR using 2 models of interpretation. Model 1 was concordant with lcWGS results in 54% of samples, for model 2 it was 46%. Although CDK genes have not been proven to be suitable CNV liquid biopsy biomarkers, lcWGS defined the most frequently affected chromosomal regions by CNV. Among chosen genes, DIP2C demonstrated a potential for further analysis.

Minimal residual disease monitoring via ctDNA: a case report of Lynch syndrome with synchronous colorectal cancer and review of literature.

Background: The investigation of circulating tumor DNA (ctDNA) as a substitute for minimal residual disease (MRD) has been a central focus in various clinical trials, with findings highlighting its effectiveness as a sensitive marker for detecting recurrence. In 2018, a joint review by the American Society of Clinical Oncology and the College of American Pathologists acknowledged a lack of current evidence guiding clinical decisions regarding ctDNA. Nevertheless, there are a multitude of ongoing studies exploring the future applications of ctDNA and its role in clinical decision making for select patient populations. Case Description: The case presented involves a patient with Lynch syndrome who developed synchronous left-sided colorectal cancers (CRC). Each primary malignancy exhibited a distinct mutational profile, introducing complexity to the personalized tumor-informed assays used for quantifying ctDNA levels. Initial ctDNA levels were negative until the assay was calibrated to the transverse colon primary tumor. Unfortunately, surveillance imaging showed radiographic recurrence coinciding with positive ctDNA findings. Treatment with the anti-PD-1 inhibitor pembrolizumab was initiated, resulting in the clearance of ctDNA after just four cycles. As of now, there is no radiographic or biologic evidence indicating disease recurrence. Conclusions: This case study sheds light on the evolving landscape and current limitations of ctDNA as a surrogate for MRD. We describe a patient with synchronous CRC who had radiographic recurrence and a negative MRD assay. Current tumor-informed assays are limited in their capacity to detect a single tumor, and by nature can miss both synchronous and metachronous malignancies. Assays tailored to multiple tumors or utilizing tumor agnostic methods should be a part of clinical decision making in this patient population.

Circulating tumor DNA to guide diagnosis and treatment of localized and locally advanced non-small cell lung cancer.

Liquid biopsy is a minimally invasive method for biomarkers detection in body fluids, particularly in blood, which offers an elevated and growing number of clinical applications in oncology. As a result of the improvement in the techniques for DNA analysis, above all next-generation sequencing (NGS) assays, circulating tumor DNA (ctDNA) has become the most informing tumor-derived material for most types of cancer, including non-small cell lung cancer (NSCLC). Although ctDNA concentration is higher in patients with advanced tumors, it can be detected even in patients with early-stage disease. Therefore, numerous clinical applications of ctDNA in the management of early-stage lung cancer are emerging, such as lung cancer screening, the identification of minimal residual disease (MRD), and the prediction of relapse before radiologic progression. Moreover, a high number of clinical trials are ongoing to better define the impact of ctDNA evaluation in this setting. Aim of this review is to offer a comprehensive overview of the most relevant implementations in using ctDNA for the management of early-stage lung cancer, addressing available data, technical aspects, limitations, and future perspectives.

CDKN2A copy number alteration in bladder cancer: Integrative analysis in patient-derived xenografts and cancer patients.

Bladder cancer (BlCa) is an extensively heterogeneous disease that leads to great variability in tumor evolution scenarios and lifelong patient surveillance, emphasizing the need for modern, minimally invasive precision medicine. Here, we explored the clinical significance of copy number alterations (CNAs) in BlCa. CNA profiling was performed in 15 patient-derived xenografts (PDXs) and validated in The Cancer Genome Atlas BlCa (TCGA-BLCA; n = 408) and Lindgren et al. (n = 143) cohorts. CDKN2A copy number loss was identified as the most frequent CNA in bladder tumors, associated with reduced CDKN2A expression, tumors of a papillary phenotype, and prolonged PDX survival. The study's screening cohort consisted of 243 BlCa patients, and CDKN2A copy number was assessed in genomic DNA and cell-free DNA (cfDNA) from 217 tumors and 189 pre-treatment serum samples, respectively. CDKN2A copy number loss was correlated with superior disease-free and progression-free survival of non-muscle-invasive BlCa (NMIBC) patients. Moreover, a higher CDKN2A index (CDKN2A/LEP ratio) in pre-treatment cfDNA was associated with advanced tumor stage and grade and short-term NMIBC progression to invasive disease, while multivariate models fitted for CDKN2A index in pre-treatment cfDNA offered superior risk stratification of T1/high-grade and EORTC high-risk patients, enhancing prediction of treatment outcome. CDKN2A copy number status could serve as a minimally invasive tool to improve risk stratification and support personalized prognosis in BlCa.

Tumor-informed deep sequencing of ctDNA detects minimal residual disease and predicts relapse in osteosarcoma.

Background: Current surveillance modalities of osteosarcoma relapse exhibit limited sensitivity and specificity. Although circulating tumor DNA (ctDNA) has been established as a biomarker of minimal residual disease (MRD) in many solid tumors, a sensitive ctDNA detection technique has not been thoroughly explored for longitudinal MRD detection in osteosarcoma. Methods: From August 2019 to June 2023, 59 patients diagnosed with osteosarcoma at the First Affiliated Hospital of Sun Yat-sen University were evaluated in this study. Tumor-informed MRD panels were developed through whole exome sequencing (WES) of tumor tissues. Longitudinal blood samples were collected during treatment and subjected to multiplex PCR-based next-generation sequencing (NGS). Kaplan-Meier curves and Log-rank tests were used to compare outcomes, and Cox regression analysis was performed to identify prognostic factors. Findings: WES analysis of 83 patients revealed substantial mutational heterogeneity, with non-recurrent mutated genes accounting for 58.1%. Tumor-informed MRD panels were successfully obtained for 85.5% of patients (71/83). Among 59 patients with successful MRD panel customization and available blood samples, 13 patients exhibited positive ctDNA detection after surgery. Patients with negative post-operative ctDNA had better event-free survival (EFS) compared to those with positive ctDNA, at 1-6 months after surgery, after adjuvant chemotherapy, and more than 6 months after surgery (p < 0.05). In both univariate and multivariate Cox regression analysis, ctDNA results emerged as a significant predictor of EFS (p < 0.05). ctDNA detection preceded positive imaging in 5 patients, with an average lead time of 92.6 days. Thirty-nine patients remained disease-free, with ctDNA results consistently negative or turning negative during follow-up. Interpretation: Our study underscores the applicability of tumor-informed deep sequencing of ctDNA in osteosarcoma MRD surveillance and, to our knowledge, represents the largest cohort to date. ctDNA detection is a significant prognostic factor, enabling the early identification of tumor relapse and progression compared to standard imaging, thus offering valuable insights in guiding osteosarcoma patient management. Funding: The Grants of National Natural Science Foundation of China (No. 82072964, 82072965, 82203798, 82203026), the Natural Science Foundation of Guangdong (No. 2023A1515012659, 2023A1515010302), and the Regional Combination Project of Basic and Applied Basic Research Foundation of Guangdong (No. 2020A1515110010).

Engineering of a DNA/γPNA Hybrid Nanoreporter for ctDNA Mutation Detection via γPNA Urinalysis.

Detection of circulating tumor DNA (ctDNA) mutations, which are molecular biomarkers present in bodily fluids of cancer patients, can be applied for tumor diagnosis and prognosis monitoring. However, current profiling of ctDNA mutations relies primarily on polymerase chain reaction (PCR) and DNA sequencing and these techniques require preanalytical processing of blood samples, which are time-consuming, expensive, and tedious procedures that increase the risk of sample contamination. To overcome these limitations, here the engineering of a DNA/γPNA (gamma peptide nucleic acid) hybrid nanoreporter is disclosed for ctDNA biosensing via in situ profiling and recording of tumor-specific DNA mutations. The low tolerance of γPNA to single mismatch in base pairing with DNA allows highly selective recognition and recording of ctDNA mutations in peripheral blood. Owing to their remarkable biostability, the detached γPNA strands triggered by mutant ctDNA will be enriched in kidneys and cleared into urine for urinalysis. It is demonstrated that the nanoreporter has high specificity for ctDNA mutation in peripheral blood, and urinalysis of cleared γPNA can provide valuable information for tumor progression and prognosis evaluation. This work demonstrates the potential of the nanoreporter for urinary monitoring of tumor and patient prognosis through in situ biosensing of ctDNA mutations.

Synthesis, characterisation, and in vitro antiparasitic activity of new flavanoidal tetrazinan-6'-ones and their binding study with calf thymus DNA using molecular modelling and spectroscopic techniques.

With the developing resistance to traditional antiparasitic medications, the purpose of this study was to efficiently develop a series of six noble flavanoidal tetrazinane-6'-one derivatives by a one-pot reaction pathway. FT-IR, 1HNMR, 13CNMR, and Mass spectra were employed for the structural elucidation of the synthesized compounds (7-12). Clinostomum complanatum, a parasite infection model that has been well-established, demonstrated that all the synthesized compounds are potent antiparasitic agents. DNA is the main target for various medicinal compounds. As a result, thestudy of how small molecules attach to DNA has received a lot of attention. In the present study, we have performed various biophysical techniques to determine the mode of binding of synthesized compounds (7-12) with calf thymus DNA (ct-DNA). It was observed from the UV-visible absorbance and fluorescence spectra that all synthesized compounds (7-12) form complexes with the ct-DNA. The value of binding constant (Kb) was obtained to be in the range of 4.36---24.50 × 103 M - 1 at 298 K. Competitive displacement assay with ethidium bromide (EB), CD spectral analysis, viscosity measurements, and in silico molecular docking confirmed that ligands (7-12) incorporate with ct-DNA through groove binding only. Molecular docking studies were performed for all synthesized compounds with the calf thymus DNA and it was found that all the newly synthesized compounds strongly bind with the chain B of DNA in the minor groove with the value of binding energy in the range of -8.54 to -9.04 kcal per mole and several hydrogen bonding interactions.

Association of personalized and tumor-informed ctDNA with patient survival outcomes in pancreatic adenocarcinoma.

INTRODUCTION: Personalized and tumor-informed circulating tumor DNA (ctDNA) testing is feasible and allows for molecular residual disease (MRD) identification in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: In this retrospective analysis of commercial cases from multiple US institutions, personalized, tumor-informed, whole-exome sequenced, and germline-controlled ctDNA levels were quantified and analyzed in patients with PDAC. Plasma samples (n = 1329) from 299 clinically validated patients were collected at diagnosis, perioperatively (MRD-window; within 2-12 weeks after surgery, before therapy), and during surveillance (>12 weeks post-surgery if no ACT or starting 4 weeks post-ACT) from November 2019 to March 2023. RESULTS: Of the initially diagnosed patients with stages I-III PDAC who went for resection, the median follow-up time from surgery was 13 months (range 0.1-214). Positive ctDNA detection rates were 29% (29/100) and 29.6% (45/152) during the MRD and surveillance windows, respectively. Positive ctDNA detection was significantly associated with shorter DFS within the MRD window (median DFS of 6.37 months for ctDNA-positive vs 33.31 months for ctDNA-negative patients; HR: 5.45, P < .0001) as well as during the surveillance period (median DFS: 11.40 months for ctDNA-positive vs NR for ctDNA-negative; HR: 12.38, P < .0001). Additionally, DFS was significantly better with KRAS wildtype status followed by KRASG12R (HR: 0.99, P = .97), KRASG12D (HR: 1.42, P = .194), and worse with KRASG12V (HR: 2.19, P = .002) status. In multivariate analysis, ctDNA detection at surveillance was found to be the most significant prognostic factor for recurrence (HR: 24.28, P < .001). CONCLUSIONS: Perioperative tumor-informed ctDNA detection in PDAC is feasible across all stages and is associated with patient survival outcomes.

Baseline circulating tumor DNA predicts long-term survival outcomes for patients with early breast cancer.

Background: Circulating tumor DNA (ctDNA) is a potential biomarker not only capable of monitoring the treatment response during neoadjuvant therapy (NAT) or rescue therapy, but also identifying minimal residual disease (MRD) and detecting early relapses after primary treatment. However, it remains uncertain whether the detection of ctDNA at diagnosis, before any treatment, can predict the prognosis for patients with early breast cancer. The objective of our study was to evaluate the predictive value of baseline ctDNA for prognosis in patients with early breast cancer. Methods: A total of 90 patients with early breast cancer and 24 healthy women were recruited between August 2016 and October 2016. Peripheral blood samples were collected from patients at diagnosis, before any treatment. Blood samples were processed and subjected to targeted deep sequencing with a next-generation sequencing (NGS) panel of 1,021 cancer-related genes. The recurrence-free survival (RFS) and invasive disease-free survival (iDFS) were reported. Results: The 90 patients with breast cancer included 6 patients with ductal carcinoma in situ (DCIS) and 84 patients with invasive breast cancer. Within the cohort of patients with invasive breast cancer, ctDNA were detected in 57 patients, with a ctDNA detection rate of 67.9%. Meanwhile, no ctDNA was detected in DCIS patients. Among 84 patients with invasive breast cancer, patients with high-level ctDNA had a significantly lower RFS compared to patients with low-level ctDNA (log-rank P=0.0036). Conclusions: Our study suggested that ctDNA at diagnosis, before any treatment, could potentially serve as a biomarker to predict the prognosis for patients with early breast cancer. However, further follow-up and more studies with large sample sizes are required to confirm these findings.

Circulating tumour DNA detects somatic variants contributing to spatial and temporal intra-tumoural heterogeneity in head and neck squamous cell carcinoma.

Background: As circulating tumour DNA (ctDNA) liquid biopsy analysis is increasingly incorporated into modern oncological practice, establishing the impact of genomic intra-tumoural heterogeneity (ITH) upon data output is paramount. Despite advances in other cancer types the evidence base in head and neck squamous cell carcinoma (HNSCC) remains poor. We sought to investigate the utility of ctDNA to detect ITH in HNSCC. Methods: In a pilot cohort of 9 treatment-naïve HNSCC patients, DNA from two intra-tumoural sites (core and margin) was whole-exome sequenced. A 9-gene panel was designed to perform targeted sequencing on pre-treatment plasma cell-free DNA and selected post-treatment samples. Results: Rates of genomic ITH among the 9 patients was high. COSMIC variants from 19 TCGA HNSCC genes demonstrated an 86.9% heterogeneity rate (present in one tumour sub-site only). Across all patients, cell-free DNA (ctDNA) identified 12.9% (range 7.5-19.8%) of tumour-specific variants, of which 55.6% were specific to a single tumour sub-site only. CtDNA identified 79.0% (range: 55.6-90.9%) of high-frequency variants (tumour VAF>5%). Analysis of ctDNA in serial post-treatment blood samples in patients who suffered recurrence demonstrated dynamic changes in both tumour-specific and acquired variants that predicted recurrence ahead of clinical detection. Conclusion: We demonstrate that a ctDNA liquid biopsy identified spatial genomic ITH in HNSCC and reliably detected high-frequency driver mutations. Serial sampling allowed post-treatment surveillance and early identification of treatment failure.

Survival of Metastatic Human Papillomavirus (HPV)-Related Head and Neck Cancer Receiving Platinum-Based Triplet Induction Chemotherapy and Relevance of Circulating Tumor HPV DNA.

Objectives We aimed to examine the effectiveness of platinum-based triplet induction chemotherapy in metastatic squamous cell carcinoma of the head and neck (HNSCC) at diagnosis in terms of tumor human papillomavirus (HPV) status and the clinical relevance of circulating tumor HPV DNA (ctHPVDNA) during induction chemotherapy. Methods  Twenty-one patients were included. ctHPVDNA was longitudinally quantified using optimized digital PCR in a subset of patients. Results HPV-related HNSCC patients (N=7) had a significantly better response to induction chemotherapy than HPV-unrelated HNSCC patients (N=14) (complete or partial response rate, 100% vs. 36%, P = 0.007). Following induction chemotherapy, more HPV-related HNSCC patients than HPV-unrelated patients received radiotherapy (86% vs. 36%, P = 0.06). With a median follow-up of 26 months in surviving patients, the two-year overall survival was 86% in HPV-related HNSCC patients and 43% in HPV-unrelated HNSCC patients (P = 0.04). In two patients, ctHPVDNA levels drastically decreased after the first cycle of induction chemotherapy but turned to continuous increase after the second cycle, suggesting the acquisition of drug resistance by the end of the second cycle. Radiographic imaging after induction chemotherapy failed to identify the drug resistance. In one patient, ctHPVDNA decreased gradually but remained detectable after induction chemotherapy despite no radiographic residual disease. ctHPVDNA became undetectable during radiotherapy. Conclusion HPV-related HNSCC patients with distant metastasis at diagnosis should be treated definitively. The ctHPVDNA level reflects real-time disease activity. ctHPVDNA monitoring during induction chemotherapy could help the decision-making of the therapeutic strategy.

Phase Ib dose-escalation trial of taselisib (GDC-0032) in combination with HER2-directed therapies in patients with advanced HER2+ breast cancer.

BACKGROUND: In most patients with advanced human epidermal growth factor receptor-2-positive (HER2+) breast cancer, anti-HER2 therapies fail due to the development of acquired resistance, potentially mediated through phosphoinositide-3-kinase (PI3K) signaling. We investigated adding taselisib, an α-selective potent oral inhibitor of PI3K, to different HER2-directed regimens in order to improve disease control. PATIENTS AND METHODS: Patients (n = 68) with advanced HER2+ breast cancer were enrolled to this open-label, dose-escalation phase Ib study. The primary endpoint was defining the maximal tolerated dose (MTD) for the various taselisib-containing combinations. The secondary endpoint was safety. Exploratory endpoints included circulating tumor DNA analysis. The study included four cohorts: (A) taselisib + trastuzumab emtansine (T-DM1), (C) taselisib + trastuzumab and pertuzumab (TP), (D) taselisib + TP + paclitaxel, and (E) taselisib + TP + fulvestrant. RESULTS: Following dose escalation, the taselisib MTD was defined as 4 mg once daily. Treatment was associated with significant toxicities, as 34 out of 68 patients experienced grade ≥3 adverse events (AEs) attributed to taselisib, the most common all-grade AEs being diarrhea, fatigue, and oral mucositis. At a median follow-up of 43.8 months, median progression-free survival (PFS) for the MTD-treated population in cohorts A, C, and E was 6.3 [95% confidence interval (CI) 3.2-not applicable (NA)] months, 1.7 (95% CI 1.4-NA) months, and 10.6 (95% CI 8.3-NA) months, respectively. The median PFS for patients in cohort A with prior T-DM1 use was 10.4 (95% CI 2.7-NA) months. CONCLUSIONS: PIK3CA targeting with taselisib in combination with HER2-targeted therapies was associated with both promising efficacy and substantial toxicities.

Plasma circulating tumor DNA unveils the efficacy of PD-1 inhibitors and chemotherapy in advanced gastric cancer.

Programmed Death Receptor 1 (PD-1) inhibitors, when combined with chemotherapy, have exhibited notable effectiveness in enhancing the survival outcomes of patients afflicted with advanced gastric cancer. However, it is important to acknowledge that not all patients derive substantial benefits from this therapeutic approach, highlighting the crucial necessity of identifying efficacious biomarkers to inform immunotherapy interventions. In this study, we sought to investigate the predictive utility of circulating tumor DNA (ctDNA) as a biomarker in a cohort of 30 patients diagnosed with advanced gastric cancer, all of whom underwent first-line treatment involving PD-1 inhibitor administration alongside chemotherapy. We procured peripheral blood samples both at baseline and following the completion of two treatment cycles. Additionally, baseline tissue specimens were collected for the purpose of genomic alteration assessment, employing both 47-gene and 737-gene next-generation sequencing panels for plasma and tumor tissue, respectively. We delineated a ctDNA response as the eradication of maximum variant allele frequencies relative to baseline levels. Notably, the objective response rate among individuals exhibiting a ctDNA response proved significantly superior in comparison to non-responders (P = 0.0073). Furthermore, patients who manifested a ctDNA response experienced markedly prolonged progression-free survival (PFS) and overall survival (OS) when juxtaposed with those devoid of a ctDNA response (median PFS: 15.6 vs. 6.0 months, P = 0.003; median OS: not reached [NR] vs. 9.0 months, P = 0.011). In summation, patients with advanced gastric cancer receiving first-line treatment with PD-1 inhibitors and chemotherapy, dynamic changes in ctDNA can serve as a potential biomarker for predicting treatment efficacy and long-term outcomes.