This is a Prospective，Single-center，Single-arm，Open-label exploratory clinical trial evaluating the efficacy and safety of Conversion Surgery for Apatinib plus SOX for patients with unresectable gastric cancer.

Gastric cancer is the second most common cause of cancer-related deaths worldwide, and surgical resection during the early stage has improved treatment outcomes.However, many patients are diagnosed with unresectable advanced or metastatic stage disease losing the radical surgery opportunity. Systemic chemotherapy is the leading treatment that prolongs survival times for such patients.

Approximate 20 patients with unresectable gastric cancer will be enrolled in this study,the investigators will evaluate the efficacy and security of Apatinib + SOX(oxaliplatin+S-1) for unresectable gastric cancer.

Inclusion Criteria:

1. Histologically proved gastric adenocarcinoma;

2. At least a unresectable factor before operation via CT, MRI, or PET-CT: difficult resection of locally advanced gastric cancer(T4b); hepatic metastasis (H1; at most five lesions, total diameter ≤8 cm); Peritoneal metastasis(CY1, P1) ;

3. Definitely diagnosed as unresectable gastric cancer via exploratory laparoscopy or laparotomy;

4. ECOG performance status 0-2;

5. Age 18-70 years old, Life expectancy estimated than 3 months;

6. For results of blood routine test and biochemical tests:

   1. Hgb ≥ 80g/L,
   2. WBC ≥ 4000/mm3,
   3. ANC ≥ 1.5×109/L,
   4. platelets ≥ 80×109/L
   5. ALT and AST ≤ 2.5 x upper normal limit (UNL), and ≤ 5 x UNL（Hematogenous metastases）,
   6. Serum Total bilirubin ≤ 1.5 X UNL,
   7. Serum Creatine ≤ 1.5 x UNL ；

7. Good cardiac function before the recruitment, no seizure of myocardial infarction in past half years, and controllable hypertension and other coronary heart disease;

8. Not concomitant with other uncontrollable benign disease before the recruitment(e.g. the infection in the kidney, lung and liver);

9. informed consent.

Exclusion Criteria:

1. Subjects with poor-controlled arterial hypertension (systolic blood pressure> 140 mmHg and diastolic blood pressure > 90 mm Hg) despite standard medical management; Coronary heart disease greater than Class I; I-level arrhythmia (including QT interval prolongation, for man ≥ 450 ms, for woman ≥ 470 ms) together with Class I cardiac dysfunction; Patients with positive urinary protein;
2. Factors that could have an effect on oral medication (such as inability to swallow, chronic diarrhea and intestinal obstruction);
3. Subjects with high gastrointestinal bleeding risk, including the following conditions: local active ulcer lesions with positive fecal occult blood test (++); history of black stool, or vomiting blood in the past 2 months;
4. Contraindications include allergy to apatinib and/or its accessories, active bleeding, intestinal perforation, intestinal obstruction, within 30 days after surgery, drugs with poor-controlled hypertension, Class Ⅲ-Ⅳ cardiac dysfunction （NYHA standard）, severe hepatic and renal dysfunction（level 4）if apatinib use is considered;
5. Abnormal Coagulation (INR>1.5, APTT>1.5 UNL), with tendency of bleed;
6. Pregnant or lactating women;
7. Any other condition that might place the patient at undue risk or preclude a patient from completing the study;
8. Treatment with prior radiotherapy, chemotherapy, Targeted therapy or immunotherapy;
9. Other conditions regimented at investigators' discretion.