Using blood tests for circulating tumor DNA to guide treatment in gastric cancer

A Prospective Phase II Study of Dynamic Circulating Tumor DNA to Predict and Guide Systemic Treatment in Patients With Gastric Cancer

This will test whether regular blood tests that measure circulating tumor DNA can help guide systemic treatment for adults with gastric or gastroesophageal junction adenocarcinoma.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 600 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Fudan University (Academic / other)
• Drugs / interventions: chemotherapy, immunotherapy
• Locations: 1 site (Shanghai)
• Trial ID: NCT07517107 on ClinicalTrials.gov

What this trial studies

This is a prospective, open-label, single-center phase II study conducted at Fudan University Shanghai Cancer Center. Patients are enrolled into three cohorts based on treatment stage: neoadjuvant/conversion therapy, adjuvant therapy after curative surgery, or advanced/metastatic disease. Participants receive standard systemic therapy while undergoing serial blood sampling for circulating tumor DNA (ctDNA) analysis, and ctDNA trends may be used to inform treatment decisions alongside imaging and clinical assessment. Key endpoints include the relationship between ctDNA dynamics and treatment response, detection of minimal residual disease, and potential impact on treatment selection and outcomes.

Who should consider this trial

Good fit: Adults (≥18 years) with histologically confirmed gastric or gastroesophageal junction adenocarcinoma, ECOG 0-2, adequate organ function, and planned for neoadjuvant, adjuvant, or systemic therapy who can provide informed consent and serial blood samples are ideal candidates.

Not a fit: Patients whose tumors shed little or no ctDNA, those with severe organ dysfunction or very limited life expectancy, or those unable to attend the single-site visits are unlikely to benefit from this approach.

Why it matters

Potential benefit: If successful, this approach could detect response or recurrence earlier and help personalize systemic therapy to improve outcomes and avoid ineffective treatments.

How similar studies have performed: Prior work in other cancers and early reports in gastric cancer show ctDNA can detect minimal residual disease and predict relapse, but using ctDNA to directly guide treatment decisions remains largely experimental.

Eligibility criteria

Inclusion Criteria:

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Age ≥18 years. Histologically or cytologically confirmed gastric or gastroesophageal junction adenocarcinoma.

Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.

Adequate organ function within 7 days prior to enrollment, including:

Absolute neutrophil count ≥1.5 × 10⁹/L Platelet count ≥80 × 10⁹/L Hemoglobin ≥80 g/L Total bilirubin ≤1.5 × upper limit of normal (ULN) AST and ALT ≤2.5 × ULN (≤5 × ULN in case of liver metastases) Serum creatinine ≤1.5 × ULN or creatinine clearance ≥60 mL/min Serum albumin ≥30 g/L Estimated life expectancy ≥3 months. Willingness to provide blood samples for circulating tumor DNA (ctDNA) analysis.

Signed written informed consent prior to any study-related procedures.

Cohort-Specific Inclusion Criteria:

Neoadjuvant/Conversion Cohort:

8\. Planned to receive neoadjuvant or conversion systemic therapy followed by potential surgery.

9\. Locally advanced (T3-T4a and/or N+, M0) or oligometastatic disease (≤1 metastatic organ and ≤5 lesions) considered potentially resectable after systemic therapy.

10\. No prior systemic therapy for gastric cancer.

Adjuvant Cohort:

11\. Completion of curative-intent surgery for gastric cancer. 12. Pathological stage II-III disease without distant metastasis. 13. Planned to receive standard adjuvant chemotherapy (e.g., XELOX or SOX).

Advanced Disease Cohort:

14\. Unresectable or metastatic disease not amenable to curative surgery. 15. Planned to receive systemic therapy, including chemotherapy with or without immunotherapy, as first-line or later-line treatment.

16\. At least one measurable lesion according to RECIST v1.1.

Exclusion Criteria:

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History of another malignancy within 5 years, except for adequately treated carcinoma in situ of the cervix or non-melanoma skin cancer.

Uncontrolled central nervous system metastases or primary brain tumors.

Severe or uncontrolled comorbidities, including but not limited to:

Unstable cardiovascular disease (e.g., recent myocardial infarction, unstable angina, congestive heart failure) Severe infection Active disseminated intravascular coagulation Significant bleeding tendency Significant organ dysfunction that, in the investigator's judgment, would compromise patient safety.

Symptomatic pleural effusion or ascites requiring intervention. Any condition that, in the opinion of the investigator, would make the patient unsuitable for participation in the study.

Where this trial is running

Shanghai

• Fudan University Shanghai Cancer Center — Shanghai, China (Recruiting)

Study contacts

• Principal investigator: Weijian Guo — Fudan University
• Study coordinator: Weijian Guo

Conditions Gastric Cancer