I. Radiation therapy The means of killing cancer tissues with radiation, such as alpha, beta and gamma rays produced by radioisotopes and various types of x-rays, electron rays, neutron beams, proton beams and other particle beams, is called radiation therapy (radiotherapy). Although radiation is more likely to damage cancer cells, it also damages normal cells and causes local or systemic radiation reactions. Acute reactions of radiation therapy for gastric cancer (arising soon after treatment) include loss of appetite, nausea, vomiting, weakness, weight loss, mucosal damage, bone marrow suppression, leukopenia, inhibition of secretion of various digestive enzymes such as gastric acid, and red, wrinkled, dry and slightly dark skin, etc. Most of them are not serious; late (or long-term) complications may take months or years to appear gradually, but they are usually permanent, including spinal cord, liver, kidney and stomach. Radiation damage to the liver, kidney and stomach, and even gastric perforation may occur in a few patients, but the extent and degree of damage is decreasing with advances in radiotherapy equipment and techniques. Unlike chemotherapy, radiotherapy only affects the cancer and its surrounding areas, not the whole body. Ma Enling, Department of Basic Surgery, Peking Union Medical College Hospital The existing techniques mainly include conventional radiotherapy outside the body, 3D conformal radiotherapy, intensity-modulated radiotherapy and image-guided radiotherapy. Advanced techniques such as 3D conformal radiotherapy or intensity-modulated radiotherapy can better protect the surrounding normal tissues and improve the tolerability of radiotherapy. As gastric adenocarcinoma has low sensitivity to radiation, radiotherapy alone is not effective and is adjuvant in gastric cancer treatment. There are four types of radiotherapy: preoperative, intraoperative, postoperative radiotherapy and palliative radiotherapy (i.e. to relieve obstruction or pain without prolonging life). Preoperative radiotherapy (or radiotherapy) is mainly for locally advanced or progressive gastric cancer that is not expected to be surgically resected; intraoperative radioactive particles can be left in the suspected area before closing the abdomen; postoperative radiotherapy (or radiotherapy) is mainly for T3-4 or N+ (lymph node positive) gastric cancer or R1/R2 resected patients; palliative radiotherapy is for local recurrence and/or distant metastasis, bone metastasis causing pain. It has been reported that preoperative radiotherapy can increase the surgical resection rate by about 2% and the 5-year survival rate of intermediate and advanced gastric cancer by 1%-2.5%. Some overseas studies suggest that preoperative or postoperative chemotherapy plus radiotherapy can slightly increase the 5-year survival rate compared with chemotherapy alone. In Europe and the United States, the results of phase III clinical trials indicate that radiotherapy is effective for gastroesophageal junction cancer. Radiotherapy for gastric cancer is less researched and applied in China, mainly because of the increasing tendency of perioperative chemotherapy plus R0 resection and D2 clearance in China, and there are too few studies on the benefit of radiotherapy in increasing survival rate in this case, which lacks convincing power. Chinese medicine treatment For unresectable or recurrent gastric cancer, if radiotherapy and chemotherapy are ineffective, Chinese medicine treatment is feasible. Although it cannot shrink cancer foci, some patients can have improvement in quality of life, and a few reports show that survival is not worse than chemotherapy. However, there is no international recognition of the efficacy of herbal medicine, and there is the view that this only indicates that the efficacy of chemotherapy or herbal medicine is poor in advanced patients, and basically the natural survival. Therefore, more high-level clinical studies are needed to determine whether the survival of herbal medicine is longer than the natural survival of patients without treatment, or whether it is no worse than the survival prolonged by chemotherapy, or whether it can enhance the efficacy of chemotherapy drugs. Third, supportive treatment aims to prevent, reduce patient suffering, improve quality of life, and sometimes prolong survival somewhat. It includes analgesia, correction of anemia, improvement of appetite, improvement of nutritional status, relief of obstruction, control of ascites, psychotherapy, etc. Endoscopic placement of self-expanding metal stents for patients with advanced unresectable gastric cancer obstruction is less risky and painful. Radiologists can relieve jaundice and avoid shortening survival by placing stents through percutaneous transhepatic biliary drainage (PTCD) or at the disposal of stenosis obstruction due to compression of the common bile duct by enlarged lymph nodes. In case of hemorrhage, radiologists can be asked to try vascular embolization to stop the bleeding. IV. Comprehensive treatment Since all therapies have limitations, in order to further improve the 5-year survival rate of stage III and IV gastric cancer which is still unsatisfactory, clinicians have been carrying out the comprehensive application of various therapies and have been observing which comprehensive treatments are most effective for which patients, and a lot of progress has been made, but it is still far from ideal. Postoperative review When regular follow-up is performed by monitoring symptoms, signs and ancillary tests, the aim is to monitor recurrence or treatment-related adverse effects, assess improved nutritional status, etc. Follow-up visits should include hematology, imaging, gastroscopy and other tests. The frequency of follow-up is once every 3-6 months for 3 years after surgery, once every 6 months for 3-5 years, and once a year after 5 years. Gastroscopy is performed once a year. At the follow-up visit, you should bring copies of the preoperative gastroscopy report, surgical records, postoperative pathology report and chemoradiotherapy regimen, all of which will be provided in original by the hospital if the review is done at the surgical hospital. In addition, you should bring all x-ray upper gastrointestinal barium meal imaging, CT films, and ultrasound examination reports that you have kept with you.