When external radiation therapy is used for tumors located deep in the body, the radiation must pass through the normal tissues surrounding the tumor, thus limiting the dose available to treat the tumor. One way to overcome this disadvantage is to use intraoperative radiation therapy, which involves directing radiation at the exposed tumor or tumor bed and delivering a large dose of radiation to the treatment area at once while the patient is under anesthesia. Intraoperative radiotherapy is a single high-dose irradiation that can be administered directly to the tumor, tumor bed, residual tumor foci, invasion area or lymph node metastasis drainage area under direct vision, avoiding and reducing the irradiation of vital organs and tissues near the tumor, maximizing the protection of normal tissues, improving the local control rate, without increasing surgical complications and mortality, delaying recovery time, and allowing postoperative treatment. Postoperative external radiotherapy or chemotherapy can be administered as planned to further improve the efficacy.