The goal of this study is to evaluate the consistency between in vitro tumor organoid drug sensitivity and the therapeutic efficacy of in vivo drug treatment.

Participants are required to provide one of fresh tumor tissues (including ascites, pleural effusion, biopsy tissues, palliative surgery specimens, etc.) for the purpose of culturing tumor organoids.

Inclusion Criteria:

1. Age ≥ 18 and ≤ 75 years old.

2. Metastatic pancreatic cancer with progression after second-line or higher treatment, metastatic gastric cancer with progression after third-line or higher treatment, or metastatic pancreatic or gastric cancer patients who cannot tolerate standard treatment regimens.

3. Able to provide fresh tumor tissue specimens for organoid culture, including: ascites, pleural effusion, tumor biopsy tissues, tumor surgical specimens, etc.

4. Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) score of 0-2.

5. Adequate organ function, including the following:

   • Bone marrow: Absolute neutrophil count (ANC) in peripheral blood ≥ 1.5 x 10^9/L, platelets ≥ 100 x 10^9/L, hemoglobin ≥ 80 g/L.
   • Liver: Total bilirubin ≤ 1.5 times the upper limit of normal (ULN), aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT) ≤ 3 times ULN. If liver metastases are present, aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT) ≤ 5 times ULN.
   • Kidney: Creatinine clearance ≥ 45 mL/min (using the standard Cockcroft-Gault formula) or ≤ 1.5 times ULN.

6. At least one measurable or evaluable lesion.

7. For women: Must be sterilized, postmenopausal, or using highly effective contraception during treatment and for 3 months after treatment; must not be pregnant or breastfeeding during treatment.

8. Patient compliance and geographic proximity to ensure adequate follow-up.

Exclusion Criteria:

1. Any unstable systemic disease (including systemic active infections requiring treatment, liver disease, kidney disease, or metabolic diseases, acute cerebral infarction or cerebral hemorrhage, etc.) that, in the investigator's judgment, may impair patient safety or the patient's ability to complete the study due to severe comorbidities.
2. Significant cardiovascular events: Congestive heart failure > NYHA class 2; unstable angina, active coronary artery disease (CAD) (myocardial infarction more than 1 year before the study is allowed); severe arrhythmias requiring treatment (use of beta-blockers or digoxin is allowed) or uncontrolled hypertension, etc.
3. Significant history of neurological or psychiatric disorders, including epilepsy, dementia, etc.
4. Pregnant or breastfeeding women; those of childbearing potential who are unwilling or unable to use effective contraception.
5. Other situations that the investigator judges may affect the conduct and determination of the clinical research results.