The retroperitoneal space is the area where important blood vessels travel in the abdomen, such as: abdominal aorta, inferior vena cava, renal artery and iliac artery are all in this space. Retroperitoneal tumors are mostly closely related to these important blood vessels, either compressing, wrapping or invading. This causes retroperitoneal tumors to be difficult and daunting to remove. If there is no adequate preparation before surgery, and if there is no understanding of the relationship between the tumor and blood vessels, the surgery will be rash, which will often cause intraoperative hemorrhage and endanger the patient’s life, or if the tumor is found to be closely related to blood vessels during surgery, the patient will not dare to remove it and can only do “switch surgery”, which will increase the patient’s pain and delay the treatment. Vascular surgeons are more familiar with the anatomical structure of important retroperitoneal vessels, mastering vascular-related operation techniques and having the ability to properly handle vascular-related events than doctors of other specialties. Therefore, surgical complications, tumor resection rate, operative time, and postoperative recovery are greatly improved in retroperitoneal tumor surgeries with the participation of vascular surgeons. Example: A patient, female, 58 years old, 5 years postoperative for sigmoid colon cancer, was found to have a retroperitoneal mass, which was confirmed to be a single malignant metastasis by PET-CT. CT film: In this case, the retroperitoneal tumor was closely related to the abdominal aortic bifurcation, common iliac artery and ureter, which is often difficult for surgeons of other specialties (not to look down on colleagues, but there are specialties in the field, only this), but the vascular surgeon could face it with ease. Intraoperative pictures: 1. The tumor is located in the bifurcation of the abdominal aorta. 2. The lower segment of the abdominal aorta and the distal and proximal segments of the left and right common iliac arteries were controlled respectively, so that bleeding was not a concern and the tumor was free from the tumor with ease. Even if the vessel ruptures during the freeing process, since the distal and proximal segments of the vessel have been controlled, there will not be a lot of bleeding, and the intraoperative visualization is clear, and vascular sutures can be given. 3. The tumor has been completely freed. 4.The situation after resection. In this case, the operation time was one and a half hours, with intraoperative bleeding of 50ml, which was less traumatic to the patient. The tumor was removed completely and the future survival time was guaranteed. The biggest beneficiary is the patient. If the tumor is found intraoperatively to be so tightly adherent to an artery or vein that it cannot be separated, or if there is also tumor tissue behind the vessel, then it can be removed along with the involved vessel and reconstructed with an autologous or artificial vessel! With this method, unless the tumor is iron-clad with the back or pelvis, there are few cases that cannot be removed. In conclusion, the safety and success rate of retroperitoneal tumor surgery are greatly increased with the escort of a vascular surgeon!