Radiotherapy for adenoid cystic carcinoma of the head and neck

Abstract

Summary Adenoid cystic carcinoma of the head and neck is a rare malignant tumor, accounting for approximately 1％ of all head and neck malignancies. Tumor growth is relatively slow and the short-term prognosis is good. However, the tumor is accompanied by extensive local tissue invasion and perineural invasion, leading to distant metastasis, especially in the lungs. Therefore, the long-term prognosis is considered to be poor. Radical surgery is the standard treatment for patients with adenoid cystic carcinoma. However, even in cases that are determined to be resectable, complete resection is often difficult due to strong invasion of adjacent tissues, especially the nerves. Therefore, postoperative radiotherapy is considered an important adjuvant treatment. Although adenoid cystic carcinoma is regarded as a radioresistant tumor, radiotherapy has recently progressed and the results of definitive radiotherapy for unresectable cases have been reported. In this review, we report on postoperative radiotherapy and definitive radiotherapy（photon and particle therapy）for adenoid cystic carcinoma of the head and neck.