The purpose of this trial is to evaluate the efficiency and safety of Chidamide in advanced
cephalic and cervical adenoid cystic carcinoma. Chidamide is given to patients with advanced
cephalic and cervical adenoid cystic carcinoma with the dosage of 30mg,twice a week, then
overall survival, event-free survival are accessed for efficiency, and laboratory tests about
the function of vital organs are accessed for safety.