As the incidence of cancer climbs, people increasingly hear about radiotherapy and chemotherapy, which are the main treatments for cancer patients in addition to surgical treatment. This brother and three children are the three major killers in the martial arts, specializing in escorting tumor patients and killing the abominable tumor king. For surgery, we can understand it literally, but radiotherapy and chemotherapy are two brothers who look like each other, so many people are confused about who is who and often confuse them. The first, the weapons used are different Radiotherapy is called radiation therapy, he is a brilliant physicist, able to use a variety of different energy rays to deal with tumor Jun, in order to inhibit and kill tumor cells of a treatment method. His weapon is the machine that can produce all kinds of rays, commonly the electron linear gas pedal. And chemotherapy is the excellent chemopharmacologist who is good at applying chemical drugs (including endocrine drugs, etc.) to fight with tumor-king. It is commonly used intravenously, orally or in other forms to let chemotherapy drugs enter the body to kill the tumor. Secondly, the scope of attack is different. Radiotherapy and surgery are good at fighting, and the attack on the local area is stronger and stronger, the scope of radiotherapy is called “target area”, that is, the area where the radiation is concentrated. After determining the size of the tumor and its invasion site based on imaging and other clinical examinations, radiotherapists must also understand the biological characteristics of the tumor and the rule of spread before deciding the radiation scope. Chemotherapy is a systemic treatment, and the drugs will be distributed to all parts of the body after entering the body, which will not only have an effect on solid tumors, but also have a strong killing effect on small invisible metastases. Of course, there are also local treatment-based chemotherapy such as interventional chemotherapy, local infusion chemotherapy and so on. Thirdly, the attack objects are different. Radiotherapy mainly targets the radical treatment of relatively limited solid tumors, such as head and neck tumors, lung cancer, esophageal cancer, skin cancer, lymphoma, etc.; the preoperative and postoperative adjuvant treatment of some tumors, such as breast cancer, cervical cancer, gastrointestinal tumors; some other tumors, such as bone and brain metastases, palliative radiotherapy, etc., while for systemic tumors, such as leukemia, the effect is limited. At present, about 70% of tumor patients need to receive radiotherapy at different stages of the disease process, which shows the importance of radiotherapy in tumor treatment. Chemotherapy is used for tumors that are sensitive to chemotherapy drugs, such as lymphoma, leukemia and other hematologic diseases, breast cancer, gastrointestinal tumors, lung cancer, reproductive tumors and so on. The effect of chemotherapy depends on the type and condition of the tumor, some of which can be cured and more often inhibit the growth and spread of the tumor. With the emergence of new technologies, the indications for radiotherapy are changing. Fourthly, the toxic side effects are different. In general, radiotherapy is mainly local reactions, which are related to the radiation field. For example, head and neck radiotherapy may cause dry mouth, sore throat, neck fibrosis, loss of taste function, etc. Radiotherapy to the chest may result in radioactive lung changes, radioactive esophagitis, etc. With the advancement of radiotherapy technology, radioactive brain damage and paraplegia, which used to occur frequently, are less common. The main reactions to chemotherapy are systemic reactions, usually bone marrow suppression, gastrointestinal reactions, such as decreased blood count, nausea, vomiting, and phlebitis. With proper management, serious liver and kidney damage, cardiac damage, and severe reactions such as “vomiting out the bile” are not very common in clinical practice. Nowadays, technology is developing, and the toxic side effects of radiotherapy are gradually being reduced. Although radiotherapy and chemotherapy are so different, in fact, radiotherapy, chemotherapy and surgery are used in conjunction with each other in the treatment of many tumors. Breast cancer and lung cancer are the most common cases of comprehensive treatment. As for when a tumor should be operated, when it should be treated with radiotherapy, when it should be treated with chemotherapy, and when it should be treated with palliative care, it depends on the clinicians, imaging physicians, pathologists and related medical personnel to make a decision through a comprehensive judgment of the patient’s disease stage, physical condition and other general conditions.