As2O3 may be a treatment option for adenoid cystic carcinoma of salivary gland.

Adenoid cystic carcinoma (ACC) is an uncommon tumor of the head and neck that may occur in any salivary gland tissue. Discouraging treatment outcomes may be related to perineural spread, loco regional invasion, and an unusually high incidence of metastatic potential. It presents a number of challenges related to facial nerve management and disease extension into surrounding soft tissue and bony compartments. ACC mostly occurring in the major and minor salivary glands, has some unique characteristics such as slow growth, diffuse invasion, and high incidence of distant metastasis. It is a high malignant carcinoma characterized by intensive local invasion and insidious distant metastasis to the lung at an early stage, which is responsible for a poor long-term survival rate. The main clinical treatment to adenoid cystic carcinoma depended on surgical operation in the past. However, it was not so easy to completely excise adenoid cystic carcinoma which resulting in the residual of tumor cells. Therefore, radiotherapy was often used after the operation. Radiotherapy alone cannot achieve the goal of radical cure, but operation combined with radiotherapy can evidently reduce the post-operative recurrence rate and increase the survival rate. Adenoid cystic carcinoma is not sensitive to conventional chemotherapeutics, so it is necessary to explore a new kind of drug which possesses inhibition and killing effects to this tumor. Arsenic trioxide (A(S2)O(3), ATO), a trivalent inorganic arsenite, has been proved to be an effective therapeutic agent against acute promyelocytic leukemia. Numerous reports have revealed that arsenite exerts its therapeutic activity by induction of apoptosis. It also induces apoptosis in a variety of cancer cells over a wide dose range. A(S2)O(3) may become a treatment option for adenoid cystic carcinoma of salivary gland.