Investigating Multigene Methylation Dynamics in Treatment Response Surveillance for Gastric Cancer

Tumor Markers (including CEA, AFP, CA125, CA19-9, CA72-4, etc.)

Tumor Markers (including CEA, AFP, CA125, CA19-9, CA72-4, etc.) results will be extracted from historical medical records, with test dates typically ranging from baseline (within 3 months pre-enrollment) to follow-up intervals aligned with standard clinical practice (e.g., every 3-6 months post-treatment). These time points may not synchronize with the methylation assessment schedule.

Time frame: Group one: Preoperative, 1 week, 1 month, 3 months, 6 months, 1 year, 1.5 years, 2 years, 3 years, 4 years, and 5 years postoperatively.

Imaging Examinations (including contrast-enhanced CT, PET/CT, ultrasound, X-ray, magnetic resonance imaging, etc.)

Imaging examinations (including contrast-enhanced CT, PET/CT, ultrasound, X-ray, magnetic resonance imaging, etc.) results will be collected from patient records. Imaging time points are determined by clinical needs (e.g., pre-treatment staging, 3-month post-treatment follow-up), with intervals independent of the methylation analysis schedule. The minimum interval between imaging and methylation sampling will be recorded.

Time frame: Group one: Preoperative, 1 week, 1 month, 3 months, 6 months, 1 year, 1.5 years, 2 years, 3 years, 4 years, and 5 years postoperatively.

Endoscope

Endoscoping results will be collected from patient records. Imaging time points are determined by clinical needs (e.g., pre-treatment staging, 3-month post-treatment follow-up), with intervals independent of the methylation analysis schedule. The minimum interval between imaging and methylation sampling will be recorded.

Time frame: Group one: Preoperative, 1 week, 1 month, 3 months, 6 months, 1 year, 1.5 years, 2 years, 3 years, 4 years, and 5 years postoperatively.

Tumor Markers (including CEA, AFP, CA125, CA19-9, CA72-4, etc.)

Tumor Markers (including CEA, AFP, CA125, CA19-9, CA72-4, etc.) results will be extracted from historical medical records, with test dates typically ranging from baseline (within 3 months pre-enrollment) to follow-up intervals aligned with standard clinical practice (e.g., every 3-6 months post-treatment). These time points may not synchronize with the methylation assessment schedule.

Time frame: Group two: pre-neoadjuvant therapy baseline, 1 week following neoadjuvant therapy, and postoperatively at 1 week, 1 month, 3 months, 6 months, 1 year, 18 months (1.5 years), 2 years, 3 years, 4 years, and 5 years

Imaging Examinations (including contrast-enhanced CT, PET/CT, ultrasound, X-ray, magnetic resonance imaging, etc.)

Imaging examinations (including contrast-enhanced CT, PET/CT, ultrasound, X-ray, magnetic resonance imaging, etc.) results will be collected from patient records. Imaging time points are determined by clinical needs (e.g., pre-treatment staging, 3-month post-treatment follow-up), with intervals independent of the methylation analysis schedule. The minimum interval between imaging and methylation sampling will be recorded.

Time frame: Group two: pre-neoadjuvant therapy baseline, 1 week following neoadjuvant therapy, and postoperatively at 1 week, 1 month, 3 months, 6 months, 1 year, 18 months (1.5 years), 2 years, 3 years, 4 years, and 5 years

Endoscope

Endoscoping results will be collected from patient records. Imaging time points are determined by clinical needs (e.g., pre-treatment staging, 3-month post-treatment follow-up), with intervals independent of the methylation analysis schedule. The minimum interval between imaging and methylation sampling will be recorded.

Time frame: Group two: pre-neoadjuvant therapy baseline, 1 week following neoadjuvant therapy, and postoperatively at 1 week, 1 month, 3 months, 6 months, 1 year, 18 months (1.5 years), 2 years, 3 years, 4 years, and 5 years