The purpose of this study is to investigate the efficacy and safety of intraperitoneal and intravenous paclitaxel plus apatinib and S-1 in the conversion therapy of gastric cancer with positive exfoliative cancer cells

Inclusion Criteria:

1. Untreated (e.g. chemotherapy, radiotherapy and other antitumor therapy);

2. Age:18 to 70 years old;

3. Man or female (except pregnant and lactating women);

4. Confirmed to gastric adenocarcinoma;

5. Proven gastric cancer of T stage was T3 and T4, and no distant metastasis was observed. The exfoliative cancer cells detection in peritoneal washes was positive;

6. Blood cell count has to meet the following criteria:

   WBC≥3.5×109/L; ANC≥1.5×109/L; PLT≥100×109/L; HB≥90g/L;

7. Liver/kidney function has to meet the following criteria:

   ALT and AST≤2.5*ULN TBIL<1.5*ULN； Serum creatinine ≤1.5*ULN;

8. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1;

9. Participants were willing to join in this study, good adherence and written informed consent.

Exclusion Criteria:

1. Patients with other malignant tumors within 5 years;
2. Metastasis was found to be visible to the naked eye;
3. It has serious or uncontrolled heart diseases and infections (Including atrial fibrillation, angina pectoris, cardiac insufficiency, ejection fraction less than 50%, poor-controlled hypertension and so on);
4. History of psychiatric drugs abuse and can't quit or patients with mental disorders;
5. Patients with severe or uncontrollable mental illness;
6. Patients with tendency of gastrointestinal bleeding, including the following: a local active ulcerative lesions, and defecate occult blood (+ +).Has melena and hematemesis in two months;
7. Pregnant or lactating women;
8. It have serious harm to the patient's safety or affect the patients who have completed the research.
9. The researchers think inappropriate.