Both radiotherapy and chemotherapy are common treatment modalities for malignant tumors, both of which have certain side effects and should be selected by doctors according to patients’ specific conditions and disease stages in the treatment process. The specific differences between radiotherapy and chemotherapy are as follows: 1) Modality: Radiotherapy is a physical treatment modality, mainly through radiation irradiation to achieve the corresponding therapeutic effect. Chemotherapy is a form of chemotherapy, mainly through oral administration, intravenous injection, arterial cannulation, intraperitoneal infusion and other means to inject the corresponding drugs into the patient’s body, so as to play the role of anti-cancer; 2, principle: radiotherapy mainly transmits energy to cancer cells through radiation, triggering structural and activity changes of cancer cells, so as to kill them. Chemotherapy is based on the infusion of chemical drugs into the patient’s body to affect the synthesis and replication of cancer cells, inhibit their growth, reproduction and differentiation, and thus kill them; 3. Chemotherapy works on the whole body and is applicable to malignant tumors such as blood system and lymphatic system, and is more suitable for middle and late stage cancer foci with metastasis, which often causes systemic side effects such as fever, nausea, vomiting and bone marrow suppression.