1.What is salivary gland cancer? There are three pairs of salivary glands in human body, parotid gland, submandibular gland and sublingual gland. There are also many small salivary glands in the mouth, such as palate, lip, tongue, etc. As the name suggests, salivary gland cancer is the general term of malignant tumors occurring in these tissues. Total salivary gland tumors, including benign and malignant, are about 1/100,000, while malignant incidence is more common in elderly people and in recent years, salivary gland cancer is also more common in children and young people. The latest pathological classification has 24 types, the common ones are adenoid cystic carcinoma, mucinous epidermis-like carcinoma, etc. According to the pathological nature, it can be classified as high, medium or low malignancy. The causes of salivary gland cancer are unclear. 2.Symptoms of salivary gland cancer are usually localized masses of benign and malignant salivary gland tumors. When the tumor is small, the human body does not feel it obviously, but when it grows up, it will form an obvious lump. Low malignant tumors do not have obvious conscious symptoms, and most of them are found by chance. Highly malignant tumors occurring in the parotid area will have early pain and invasion of nerves will cause facial paralysis, and some tumors will have local metastases in the lymph nodes of the neck and systemic metastases such as lung. 3.How to diagnose salivary gland cancer? 1) Clinical symptoms: accelerated growth, fixed mass, pain, facial palsy, enlarged regional lymph nodes, etc. 2)The location of tumor, different glands are different, the texture of tumor, malignant tumor is harder in texture. The mobility of tumor, nerve involvement performance. 3)Auxiliary examination CT film can see the gland is destroyed or squeezed and shifted by a mass with unclear boundary. 4) Puncture biopsy or excisional biopsy of parotid area unless the possibility of malignant tumor is judged from all aspects and for clinical verification for next treatment design, biopsy is generally not advocated and fine needle aspiration cytology or hollow needle aspiration biopsy can be performed. Submandibular gland tumor is also generally not advocated for biopsy. Other parts can be biopsied. 4.How should salivary gland cancer be treated? What are the methods of treatment? 1) Surgery with selective enlargement of resection. If the nerve has been invaded, consider resecting the nerve and doing nerve transplantation if possible. If the adhesions are not too strong, consider preserving the nerve to improve the patient’s quality of life. The scope of resection varies for different types of tumors and different parts of the tumor. 2) Radiation therapy is not suitable for adenocarcinoma because it is not sensitive to radiation, but postoperative adjuvant therapy can improve the efficacy. For those who are not suitable for surgery in late stage, palliative radiotherapy has certain control effect, but it cannot achieve the purpose of radical cure. Radioactive particle therapy is a kind of radiotherapy, in which radioactive nuclide is implanted into the area in need of radiotherapy through puncture needle according to the design, and radiation therapy is carried out, with the advantages of large local dose and small side effects. 5.What is the prognosis of salivary gland cancer? The overall prognosis of salivary gland cancer is good, and after standardized treatment, it has been reported in the literature that the 5-year local control rate can reach 70%-80% and the 5-year survival rate 80%-90%, however, different sites, different tumor types, different tumor stages and different treatment methods have great influence on the prognosis. The local recurrence rate was 62% in patients without radiotherapy, while the local recurrence rate was only 20% in those who combined with radiotherapy after surgery. The 10-year local control rate and survival rate of T4 patients is only 21%. In conclusion, the earlier the cancer is treated, the better the outcome, while the outcome of late stage cancer is poor. Low malignant cancers have better outcomes, while highly malignant cancers have poor outcomes. The efficacy is good for those without distant metastasis and poor for those with distant metastasis.6. The importance of regular review is to detect the recurrent lesion at the earliest time when it is the smallest, so that it is easy to treat again, if the scope of recurrent lesion is large, the treatment is relatively complicated and some lesions invade important structures and lose the chance of treatment. The recurrence of salivary gland cancer is 80% within 3 years after treatment, and recurrence can be seen 5 or 8 years after treatment.