When many people hear about any cancer, the first thing that comes to their mind is surgical removal, which is actually a wrong concept. For some early stage and localized cancers, the treatment effect is better with modern radiotherapy technology. Which cancers are suitable for radiotherapy? Early stage laryngeal cancer, cervical cancer, nasopharyngeal cancer can be cured by radiotherapy, lung cancer, liver cancer, pancreatic cancer, lung metastatic cancer, liver metastatic cancer and retroperitoneal tumors can be treated by modern radiotherapy technology, and the effect has been significantly improved. Radiotherapy is to destroy tumor cells through ionizing radiation to control the tumor from growing. At the same time, it makes the normal tissues around the tumor have less adverse reactions. Although radiotherapy and surgery are both local treatments, radiotherapy can treat some organ tumors in a way that surgery cannot. Especially for some people who are not suitable for surgical treatment such as old age, weak physique, etc. or tumors with very poor efficacy of surgical treatment, it is one more choice. For early stage laryngeal cancer, cervical cancer, nasopharyngeal cancer, etc., modern radiotherapy technology has better efficacy and fewer side effects. For lung cancer, liver cancer, pancreatic cancer, lung metastatic cancer, liver metastatic cancer and retroperitoneal tumors, the effect has also been greatly improved. Clinical practice also shows that the 5-year survival rate of modern radiotherapy for treating stage I-IV nasopharyngeal carcinoma has been increased to 75%, the 5-year survival rate for treating early nasopharyngeal carcinoma is more than 90%, and the 5-year survival rate for treating early non-small-cell lung carcinoma has been increased to about 70%. Modern radiotherapy technology can treat tumors as long as imaging can detect them, and the earlier the better, the smaller the striking surface and the higher the cure rate. Radiotherapy, as it is called, is not only used for the individual treatment of certain cancers, but also commonly used for the consolidation treatment of cancers before or after surgery. It can be used before surgery to shrink the tumor body, stabilize the condition and fix the tissues, which is conducive to surgical stripping; it can be used after surgery to kill the residual cancer cells that cannot be removed by surgery, cut off the source of cancer and prevent recurrence. Radiotherapy utilizes radiation to inhibit and kill cancer cells to achieve the purpose of treatment. Since there are differences in the source, location, size and physical condition of cancerous tumor, the sensitivity of various types of cancerous tumors to radiation varies greatly. Clinically speaking, the most sensitive to radiation is also the one with the best therapeutic effect, such as leukemia, lymphosarcoma, anaplastic cell tumor; the moderately sensitive ones, such as skin cancer, uterine cervix cancer, esophageal cancer, lip cancer, breast cancer, thyroid cancer, etc.; and the least sensitive ones, such as osteosarcoma, liposarcoma, malignant melanoma, etc., have poor therapeutic effect. Although radiotherapy can destroy cancer cells, it also has the destructive side of damaging a certain number of normal tissues, so there will be some local and systemic damages and reactions. Such as local tissue swelling, skin congestion, pigmentation, keratinization of hair follicles, dry skin peeling, hair loss, etc.; the whole body will have weakness, nausea, loss of appetite, insomnia, drop of white blood cells, etc. However, there is no need to be nervous about this, because the vast majority of the cancer cells will be destroyed by radiation therapy, and the majority of the cancer cells will be damaged. However, there is no need to be nervous about this, because the vast majority of patients can recover after taking palliative drugs, generally without sequelae. For tumor patients who will undergo or are undergoing radiotherapy, doctors can take certain measures to reduce the side effects of radiotherapy to the lowest degree.