A Prospective Study on Predicting Recurrence Risk of Postoperative High-risk GISTs in NED State Based on MRD Detection Via Liquid Biopsy

The goal of this single-center, prospective, observational cohort study is to learn whether tumor-informed minimal residual disease (MRD) testing in blood can predict recurrence in 66 patients with high-risk gastrointestinal stromal tumor (GIST) who are not currently receiving postoperative adjuvant therapy. The main questions it aims to answer are: Can changes in MRD during follow-up predict tumor recurrence? How closely do MRD results agree with contrast-enhanced computed tomography (CT) findings, and can MRD identify recurrence earlier than CT? Can tumor genomic features, changes in MRD, and clinicopathological features be combined to develop a model for predicting recurrence risk? Participants will have their surgical tumor tissue analyzed, provide blood samples for MRD testing, and undergo regular clinical follow-up and contrast-enhanced CT examinations for 3 years. Participants may choose to receive and discuss their MRD results. This study will not assign or change treatment based on MRD results. Recurrence and treatment decisions will remain based on routine clinical assessment, primarily contrast-enhanced CT and multidisciplinary review.

Inclusion Criteria: I. Inclusion Criteria for the Prospective Study on Postoperative Minimal Residual Disease (MRD) Surveillance in High-Risk Gastrointestinal Stromal Tumors (GIST) Without Adjuvant Therapy 1. Aged 18-75 years. 2. Patients suspected of having high-risk GIST based on preoperative imaging, or patients with biopsy-confirmed high-risk GIST who have not received preoperative neoadjuvant therapy. 3. Treatment-naive patients who have not previously received radiotherapy, chemotherapy, surgery, or any other anticancer treatment. 4. Adequate hepatic, renal, and other major organ function, with the patient considered medically fit to undergo surgery. 5. Postoperative pathological confirmation of gastrointestinal stromal tumor. 6. Tumor genotyping demonstrating a genotype associated with primary resistance to imatinib, such as a PDGFRA D842V mutation, or a clear decision by the patient to decline postoperative adjuvant imatinib therapy. 7. A definite contraindication to imatinib or another targeted therapy. 8. Patients who underwent R0 resection of the primary tumor, completed long-term postoperative adjuvant therapy, and discontinued treatment at least 3 months previously. 9. The patient and family members are able to understand the study protocol; the patient voluntarily agrees to participate and provides written informed consent. II. Inclusion Criteria for the Development of a Genomics-Based Recurrence Risk Prediction Model for High-Risk GIST and Identification of the Optimal Target Population for MRD Surveillance a. The inclusion criteria are identical to those of the prospective study on postoperative MRD surveillance in high-risk GIST without adjuvant therapy. Exclusion Criteria: I. Exclusion Criteria for the Prospective Study on Postoperative Minimal Residual Disease (MRD) Surveillance in High-Risk Gastrointestinal Stromal Tumors (GIST) Without Adjuvant Therapy 1. A history of another malignant tumor or the presence of another concurrent malignancy. 2. Emergency surgery required because of intestinal obstruction, perforation, bleeding, or a similar condition. 3. Pregnancy or breastfeeding. 4. A history of severe psychiatric illness. 5. Any contraindication to surgical treatment. 6. Failure to achieve R0 resection. 7. Low- or intermediate-risk disease according to postoperative pathological risk stratification. 8. Presence of distant metastasis. 9. Any other condition that, in the investigator's judgment, renders the patient unsuitable for enrollment. II. Exclusion Criteria for the Development of a Genomics-Based Recurrence Risk Prediction Model for High-Risk GIST and Identification of the Optimal Target Population for MRD Surveillance a. The exclusion criteria are identical to those of the prospective study on postoperative MRD surveillance in high-risk GIST without adjuvant therapy.