Patient: Description (time of onset, main symptoms, hospital visited, etc.): Dr. Bu, I consulted you on April 23rd at your clinic, and now I have a few questions to consult you again through the internet. My mother has adenoid cystic carcinoma of the floor of the mouth, and the doctor at Qilu Hospital said that the tumor was 4cm in diameter. No treatment has been done. What kind of help do I need: You said that this kind of cancer is best treated by implanting radioactive particles, but I would like to ask how many particles should be implanted for a tumor of 4cm in diameter? If the tumor is removed surgically and then implanted with particles, is the number of implants the same as the number of particles implanted directly without removal? Also, what is the chance of cure with implanted particles? Is it easy to recur? BU Rongfa, Department of Stomatology, Beijing 301 Hospital: Adenoid cystic carcinoma is generally difficult to be removed due to its neurophilic nature and early occurrence of distant metastasis, and although it grows slowly, it is extremely aggressive. Traditional radiotherapy is almost ineffective. The effect of fast neutron radiotherapy is six times that of ordinary radiotherapy, but it is far less than that of radioactive particles. Adenoid cystic carcinoma has the following characteristics: 1. the scope of lesion under the naked eye does not match with that under the microscope; a lesion of 1 cm can not be cut after extensive resection of several centimeters; 2. the extent of lesion does not match with the systemic condition; metastasis in both lungs, the patient may not feel any discomfort; 3. the course of disease does not match with the degree of malignancy; most of adenoid cystic carcinoma can survive for more than 5 years without treatment, but the extent of local invasion, metastasis and the degree of difficulty in cutting is so high that it is difficult to be cut. The high degree of difficulty in cutting clean is very obvious. Some people already have metastases in both lungs at the time of initial diagnosis. Adenoid cystic carcinoma of the floor of the mouth usually originates from the sublingual gland or the small salivary gland of the floor of the mouth, which can be treated with radiation particles without surgery. After 1-2 months of treatment, the swelling becomes soft and disappears. Since the half-life of radioactive particles is 59 days, they have no effect at all after 200 days. If the tumor disappears completely after 2-3 months of treatment, it can be observed, or radioactive particles can be implanted again after 6 months. According to the clinical application, through more than 5 years of observation, the vast majority of them can be implanted once, there are 2 cases implanted twice and 1 case implanted 3 times. However, due to the slow growth of the disease itself, it remains to be observed whether it can be completely cured. One thing is for sure, this method is very effective in controlling the growth of adenoid cystic carcinoma, which is unlike any other method so far. The amount of radioactive particles implanted depends on the tumor volume, and the amount of radioactive particles can be significantly reduced after tumor removal.