The adverse reactions after radiotherapy for lung cancer vary slightly according to the target area and lymphatic drainage area of radiotherapy. The specific radiotherapy side effects that will be encountered in clinical practice are as follows: 1. Mainly bone marrow suppression, similar to chemotherapy will produce hematological toxicity, if it is simple radiotherapy, bone marrow suppression is lighter. If multiple courses of chemotherapy are administered and the patient has to undergo radiotherapy again, the bone marrow suppression may be heavy, mainly manifested in the decrease of white blood cells, platelets and hemoglobin; 2. damage to the skin in the radiation area, the damage is mainly manifested in skin pigmentation, skin breakdown, and some patients may have infection. Of course, this is more common in the head and neck radiotherapy, mainly pigmentation is more common, doctors will tell patients to protect the skin, generally can adhere to radiotherapy; 3, radiation esophagitis, mainly manifested as swallowing difficulties, eating obstruction, generally after a week of radiotherapy will appear, some patients in a week after radiotherapy until the end of radiotherapy, including the end of radiotherapy will have symptoms for a period of time Some patients may not have symptoms until the end of radiotherapy, but some patients can tolerate it well, so it may not appear. 4. Radiation lung damage, because when radiation irradiates tumor, it will pass through normal lung tissue and cause damage to normal tissue.