Radiotherapy is also done in the early stage of adenoid cystic carcinoma in order to completely eliminate the tumor cells, thus improving the survival period of patients. Adenoid cystic carcinoma is a type of malignant tumor of salivary gland, and tumors occurring in sublingual gland are mostly adenoid cystic carcinoma. The tumor usually spreads along the nerves, and patients may have neurological symptoms, such as local pain, facial paralysis, hypoglossal nerve palsy, tongue numbness, and so on. The tumor is more invasive and often has no obvious boundary with surrounding tissues. If patients with adenoid cystic carcinoma are in early stage doctors also suggest radiation therapy, mostly to remove the residual kinds of cells. For some cases when surgery cannot completely remove the tumor, postoperative treatment with radiation therapy is also needed. After comprehensive treatment, the chance of recurrence can be reduced, and for some patients who cannot be operated, radiation therapy can play a role in controlling the spread of tumor. Patients with adenoid cystic carcinoma need to actively cooperate with doctors to take relevant treatment measures, so as to avoid delaying the condition. During the period of treatment, patients should follow the doctor’s instruction to have regular checkups in order to know the recovery of the disease.