Gastric cancer is one of the most common malignace worldwide, which caused a dramatically death rate, especially in east Asian, such as Japan , South Korea and China. Although the treatment of gastric cancer has a large improvement, such as radiotherapy, chemotherapy and immunotherapy, surgery is yet the mainstream method for the curable malignace without distant metastasis. As the innovation of treatment in gastric caner, laprascopic has gain its popularity owing to its equivalent oncologic outcomes, earlier oral feeding, shorten postopertative of hospital length,compared with open surgery. Depite it has several advantages, the defect of laparascopic surgery is still obvious, such as 2D surgical field, lack of inverse haptic feedback, Inflexible equipment.

D2 Lymph node dissection associated with laparascopic gastronomy is still regard as standard surgical procedure for the gastric cancer patient whose tumor stage was evaluated in advance stage. As we known that the distribution of lymph nod is accompanied with blood vessels, even for well-trained surgeon, the procedure lymph node dissection is a challenging and tough work. Computed Tomography Angiography(3D-CTA), as a emerging technology, is gradually receive the surgeon's attention for its remedy characteristic to the defect of laparascopic surgery, which can visually display the distribution and type of perigastric artery, resulting in decresing the difficulty and risk of surgery.

The aim of the study is to investigate the clinincal outcomes for the patient with BMI ≥25 kg/㎡who underwent laparascopic or robotic gastronomy using CTA to evaluate the type of perigastric artery.

Inclusion Criteria:

1. Pathological diagnosis of gastric adenocarcinoma by gastroscopy
2. Age 18~75 years old
3. BMI≥25.0kg/m2
4. Preoperative imaging staging is T1~T4a, N0~3, M0
5. The surgical approach is laparoscopic surgery and robotic surgery

Exclusion Criteria:

1. Patients whose tumors stage are found to be T4b or M1 during the operation, tumors are unresectable and accompanied with malignant tumors in other parts;
2. suffering from other malignant tumors, tumors of low malignant potential (giant cell tumor of bone, pseudomyxadenoma of appendix, invasive fibroma) in the past;
3. Patients who have serious other system diseases and cannot tolerate surgery;
4. Patients with non-adenocarcinoma type malignant tumors in pathology after surgery;
5. Patients with residual gastric cancer;
6. Those who are allergic to iodine contrast agents;
7. Those who have received neoadjuvant therapy before surgery;
8. Pregnant patients;
9. Patients who are participating in other clinical studies trial.